diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9c5beffc61130..888b7ec6626c2 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -8440,8 +8440,8 @@ namespace ts {
             return prop ? getTypeOfSymbol(prop) : undefined;
         }
 
-        function getTypeOfPropertyOrIndexSignature(type: Type, name: __String): Type {
-            return getTypeOfPropertyOfType(type, name) || getApplicableIndexInfoForName(type, name)?.type || unknownType;
+        function getTypeOfPropertyOrIndexSignature(type: Type, name: __String): Type | undefined {
+            return getTypeOfPropertyOfType(type, name) || getApplicableIndexInfoForName(type, name)?.type;
         }
 
         function isTypeAny(type: Type | undefined) {
@@ -14996,7 +14996,7 @@ namespace ts {
                         links.resolvedType = getTypeFromTypeNode(node.type);
                         break;
                     default:
-                        throw Debug.assertNever(node.operator);
+                        throw new Error("never");
                 }
             }
             return links.resolvedType;
@@ -21051,6 +21051,12 @@ namespace ts {
                 && ((target.flags & (TypeFlags.Number | TypeFlags.String | TypeFlags.Boolean)) !== 0);
         }
 
+        // `nullable == SomeType|nullable` should be true
+        function isNullableComparableUnderDoubleEquals(source: Type, target: Type): boolean {
+            return !!(source.flags & TypeFlags.Nullable) && maybeTypeOfKind(target, TypeFlags.Nullable)
+                || !!(target.flags & TypeFlags.Nullable) && maybeTypeOfKind(source, TypeFlags.Nullable);
+        }
+
         /**
          * Return true if type was inferred from an object literal, written as an object type literal, or is the shape of a module
          * with no call or construct signatures.
@@ -22698,7 +22704,8 @@ namespace ts {
                         target.kind === SyntaxKind.Identifier && getResolvedSymbol(source as Identifier) === getResolvedSymbol(target as Identifier) ||
                             (target.kind === SyntaxKind.VariableDeclaration || target.kind === SyntaxKind.BindingElement) &&
                             getExportSymbolOfValueSymbolIfExported(getResolvedSymbol(source as Identifier)) === getSymbolOfNode(target);
-                case SyntaxKind.ThisKeyword:
+                    return false;
+                    case SyntaxKind.ThisKeyword:
                     return target.kind === SyntaxKind.ThisKeyword;
                 case SyntaxKind.SuperKeyword:
                     return target.kind === SyntaxKind.SuperKeyword;
@@ -23986,7 +23993,7 @@ namespace ts {
                 if (isMatchingReference(reference, expr)) {
                     type = narrowTypeBySwitchOnDiscriminant(type, flow.switchStatement, flow.clauseStart, flow.clauseEnd);
                 }
-                else if (expr.kind === SyntaxKind.TypeOfExpression && isMatchingReference(reference, (expr as TypeOfExpression).expression)) {
+                else if (expr.kind === SyntaxKind.TypeOfExpression) {
                     type = narrowBySwitchOnTypeOf(type, flow.switchStatement, flow.clauseStart, flow.clauseEnd);
                 }
                 else {
@@ -23995,10 +24002,6 @@ namespace ts {
                             type = narrowTypeBySwitchOptionalChainContainment(type, flow.switchStatement, flow.clauseStart, flow.clauseEnd,
                                 t => !(t.flags & (TypeFlags.Undefined | TypeFlags.Never)));
                         }
-                        else if (expr.kind === SyntaxKind.TypeOfExpression && optionalChainContainsReference((expr as TypeOfExpression).expression, reference)) {
-                            type = narrowTypeBySwitchOptionalChainContainment(type, flow.switchStatement, flow.clauseStart, flow.clauseEnd,
-                                t => !(t.flags & TypeFlags.Never || t.flags & TypeFlags.StringLiteral && (t as StringLiteralType).value === "undefined"));
-                        }
                     }
                     const access = getDiscriminantPropertyAccess(expr, type);
                     if (access) {
@@ -24173,25 +24176,20 @@ namespace ts {
                     }
                 }
                 else if (isAccessExpression(expr)) {
-                    // An access expression is a candidate if the reference matches the left hand expression.
-                    if (isMatchingReference(reference, expr.expression)) {
-                        return expr;
-                    }
+                    return expr;
                 }
                 else if (isIdentifier(expr)) {
                     const symbol = getResolvedSymbol(expr);
                     if (isConstVariable(symbol)) {
                         const declaration = symbol.valueDeclaration!;
                         // Given 'const x = obj.kind', allow 'x' as an alias for 'obj.kind'
-                        if (isVariableDeclaration(declaration) && !declaration.type && declaration.initializer && isAccessExpression(declaration.initializer) &&
-                            isMatchingReference(reference, declaration.initializer.expression)) {
+                        if (isVariableDeclaration(declaration) && !declaration.type && declaration.initializer && isAccessExpression(declaration.initializer)) {
                             return declaration.initializer;
                         }
                         // Given 'const { kind: x } = obj', allow 'x' as an alias for 'obj.kind'
                         if (isBindingElement(declaration) && !declaration.initializer) {
                             const parent = declaration.parent.parent;
-                            if (isVariableDeclaration(parent) && !parent.type && parent.initializer && (isIdentifier(parent.initializer) || isAccessExpression(parent.initializer)) &&
-                                isMatchingReference(reference, parent.initializer)) {
+                            if (isVariableDeclaration(parent) && !parent.type && parent.initializer && (isIdentifier(parent.initializer) || isAccessExpression(parent.initializer))) {
                                 return declaration;
                             }
                         }
@@ -24201,60 +24199,118 @@ namespace ts {
             }
 
             function getDiscriminantPropertyAccess(expr: Expression, computedType: Type) {
-                const type = declaredType.flags & TypeFlags.Union ? declaredType : computedType;
-                if (type.flags & TypeFlags.Union) {
-                    const access = getCandidateDiscriminantPropertyAccess(expr);
-                    if (access) {
-                        const name = getAccessedPropertyName(access);
-                        if (name && isDiscriminantProperty(type, name)) {
-                            return access;
+                const access = getCandidateDiscriminantPropertyAccess(expr);
+                if (!access) {
+                    return undefined;
+                }
+                const propertyTypeInfo = getPropertyTypesFromTypeByBindingElementOrExpression(computedType, access);
+                if (!propertyTypeInfo) {
+                    return undefined;
+                }
+                const reachableFinalType = mapDefined(propertyTypeInfo, t => t.finalType);
+                const rootNullable: Type[] = (computedType.flags & TypeFlags.Union) ? (computedType as UnionType).types.filter(t => t.id === undefinedType.id || t.id === nullType.id) : [];
+
+                if (reachableFinalType.length < propertyTypeInfo.length && !some(rootNullable, t => some(propertyTypeInfo, info => info.typeId === t.id))) {
+                    return access;
+                }
+
+                if (!(computedType.flags & TypeFlags.Union)) {
+                    if (isThisTypeParameter(computedType)) {
+                        return undefined;
+                    }
+                    if (isElementAccessExpression(expr)) {
+                        const type = getReducedApparentType(computedType);
+                        if (type.flags & TypeFlags.Object) {
+                            const resolved = resolveStructuredTypeMembers(type as ObjectType);
+                            if (resolved.indexInfos) {
+                                return undefined;
+                            }
                         }
                     }
+                    return access;
+                }
+                return areTypesDiscriminable(reachableFinalType) ? access : undefined;
+
+                // main part is copied from function createUnionOrIntersectionProperty
+                function areTypesDiscriminable(types: Type[]) {
+                    let checkFlags = 0;
+                    let firstType: Type | undefined;
+                    for (const type of types) {
+                        if (!firstType) {
+                            firstType = type;
+                        }
+                        else if (type !== firstType) {
+                            checkFlags |= CheckFlags.HasNonUniformType;
+                        }
+                        if (isLiteralType(type)) {
+                            checkFlags |= CheckFlags.HasLiteralType;
+                        }
+                        if (type.flags & TypeFlags.Never) {
+                            checkFlags |= CheckFlags.HasNeverType;
+                        }
+                    }
+                    // next line is copied from isDiscriminantProperty
+                    return (checkFlags & CheckFlags.Discriminant) === CheckFlags.Discriminant && !maybeTypeOfKind(getUnionType(types), TypeFlags.Instantiable);
                 }
-                return undefined;
             }
 
-            function narrowTypeByDiscriminant(type: Type, access: AccessExpression | BindingElement | ParameterDeclaration, narrowType: (t: Type) => Type): Type {
-                const propName = getAccessedPropertyName(access);
-                if (propName === undefined) {
+            function narrowTypeByDiscriminant(type: Type, access: AccessExpression | BindingElement | ParameterDeclaration, narrowTypeCb: (t: Type) => Type): Type {
+                const propertyTypeArray = getPropertyTypesFromTypeByBindingElementOrExpression(type, access);
+                if (!propertyTypeArray) {
                     return type;
                 }
-                const removeNullable = strictNullChecks && isOptionalChain(access) && maybeTypeOfKind(type, TypeFlags.Nullable);
-                let propType = getTypeOfPropertyOfType(removeNullable ? getTypeWithFacts(type, TypeFacts.NEUndefinedOrNull) : type, propName);
-                if (!propType) {
-                    return type;
+                const reachableFinalType = mapDefined(propertyTypeArray, t => t.finalType);
+                const containsEffectiveOptionalChainTypes = propertyTypeArray.filter(t => t.containsEffectiveOptionalChain);
+                const subtypes: Type[] = [];
+                forEach(reachableFinalType, propType => {
+                    forEachType(propType, t => {
+                        subtypes.push(t);
+                    });
+                });
+                const isAnyConstituentContainsEffectiveOptionalChain = containsEffectiveOptionalChainTypes.length !== 0;
+                if (isAnyConstituentContainsEffectiveOptionalChain) {
+                    subtypes.push(undefinedType);
                 }
-                propType = removeNullable ? getOptionalType(propType) : propType;
-                const narrowedPropType = narrowType(propType);
-                return filterType(type, t => {
-                    const discriminantType = getTypeOfPropertyOrIndexSignature(t, propName);
-                    return !(narrowedPropType.flags & TypeFlags.Never) && isTypeComparableTo(narrowedPropType, discriminantType);
+                const bigUnion = getUnionType(subtypes);
+                const narrowedPropType = narrowTypeCb(bigUnion);
+                const markSet = new Set<TypeId>();
+                propertyTypeArray.forEach(propertyType => {
+                    if (propertyType.finalType && !(narrowedPropType.flags & TypeFlags.Never) && isTypeComparableTo(narrowedPropType, propertyType.finalType)) {
+                        markSet.add(propertyType.typeId);
+                    }
                 });
+                containsEffectiveOptionalChainTypes.forEach(t => {
+                    if (maybeTypeOfKind(narrowedPropType, TypeFlags.Undefined)) {
+                        markSet.add(t.typeId);
+                    }
+                });
+                return filterType(type, (t) => markSet.has(t.id));
             }
 
             function narrowTypeByDiscriminantProperty(type: Type, access: AccessExpression | BindingElement | ParameterDeclaration, operator: SyntaxKind, value: Expression, assumeTrue: boolean) {
-                if ((operator === SyntaxKind.EqualsEqualsEqualsToken || operator === SyntaxKind.ExclamationEqualsEqualsToken) && type.flags & TypeFlags.Union) {
-                    const keyPropertyName = getKeyPropertyName(type as UnionType);
-                    if (keyPropertyName && keyPropertyName === getAccessedPropertyName(access)) {
-                        const candidate = getConstituentTypeForKeyType(type as UnionType, getTypeOfExpression(value));
-                        if (candidate) {
-                            return operator === (assumeTrue ? SyntaxKind.EqualsEqualsEqualsToken : SyntaxKind.ExclamationEqualsEqualsToken) ? candidate :
-                                isUnitType(getTypeOfPropertyOfType(candidate, keyPropertyName) || unknownType) ? removeType(type, candidate) :
-                                type;
-                        }
-                    }
-                }
+                // if ((operator === SyntaxKind.EqualsEqualsEqualsToken || operator === SyntaxKind.ExclamationEqualsEqualsToken) && type.flags & TypeFlags.Union) {
+                //     const keyPropertyName = getKeyPropertyName(type as UnionType);
+                //     if (keyPropertyName && keyPropertyName === getAccessedPropertyName(access)) {
+                //         const candidate = getConstituentTypeForKeyType(type as UnionType, getTypeOfExpression(value));
+                //         if (candidate) {
+                //             return operator === (assumeTrue ? SyntaxKind.EqualsEqualsEqualsToken : SyntaxKind.ExclamationEqualsEqualsToken) ? candidate :
+                //                 isUnitType(getTypeOfPropertyOfType(candidate, keyPropertyName) || unknownType) ? removeType(type, candidate) :
+                //                 type;
+                //         }
+                //     }
+                // }
                 return narrowTypeByDiscriminant(type, access, t => narrowTypeByEquality(t, operator, value, assumeTrue));
             }
 
             function narrowTypeBySwitchOnDiscriminantProperty(type: Type, access: AccessExpression | BindingElement | ParameterDeclaration, switchStatement: SwitchStatement, clauseStart: number, clauseEnd: number) {
-                if (clauseStart < clauseEnd && type.flags & TypeFlags.Union && getKeyPropertyName(type as UnionType) === getAccessedPropertyName(access)) {
-                    const clauseTypes = getSwitchClauseTypes(switchStatement).slice(clauseStart, clauseEnd);
-                    const candidate = getUnionType(map(clauseTypes, t => getConstituentTypeForKeyType(type as UnionType, t) || unknownType));
-                    if (candidate !== unknownType) {
-                        return candidate;
-                    }
-                }
+                // if (clauseStart < clauseEnd && type.flags & TypeFlags.Union && getKeyPropertyName(type as UnionType) === getAccessedPropertyName(access)) {
+                //     const clauseTypes = getSwitchClauseTypes(switchStatement).slice(clauseStart, clauseEnd);
+                //     const candidate = getUnionType(map(clauseTypes, t => getConstituentTypeForKeyType(type as UnionType, t) || unknownType));
+                //     if (candidate !== unknownType) {
+                //         return candidate;
+                //     }
+                // }
+
                 return narrowTypeByDiscriminant(type, access, t => narrowTypeBySwitchOnDiscriminant(t, switchStatement, clauseStart, clauseEnd));
             }
 
@@ -24266,8 +24322,9 @@ namespace ts {
                 if (strictNullChecks && assumeTrue && optionalChainContainsReference(expr, reference)) {
                     type = getTypeWithFacts(type, TypeFacts.NEUndefinedOrNull);
                 }
-                const access = getDiscriminantPropertyAccess(expr, type);
-                if (access) {
+                // the union check could reference this condition: https://github.com/microsoft/TypeScript/pull/38839#pullrequestreview-618968924
+                let access;
+                if ((type.flags & TypeFlags.Union) && (access = getDiscriminantPropertyAccess(expr, type))) {
                     return narrowTypeByDiscriminant(type, access, t => getTypeWithFacts(t, assumeTrue ? TypeFacts.Truthy : TypeFacts.Falsy));
                 }
                 return type;
@@ -24447,8 +24504,8 @@ namespace ts {
                 }
                 if (assumeTrue) {
                     const filterFn: (t: Type) => boolean = operator === SyntaxKind.EqualsEqualsToken ?
-                        t => areTypesComparable(t, valueType) || isCoercibleUnderDoubleEquals(t, valueType) :
-                        t => areTypesComparable(t, valueType);
+                    (t => areTypesComparable(t, valueType) || isCoercibleUnderDoubleEquals(t, valueType) || isNullableComparableUnderDoubleEquals(t, valueType)) :
+                    t => areTypesComparable(t, valueType);
                     return replacePrimitivesWithLiterals(filterType(type, filterFn), valueType);
                 }
                 if (isUnitType(valueType)) {
@@ -24457,18 +24514,208 @@ namespace ts {
                 return type;
             }
 
+            interface NarrowDeepPropertyInfo {
+                // Direct constituent of one union type.
+                typeId: TypeId;
+                // Get the type according to path from direct constituent. `undefined` means impossiable to reach type according to path.
+                finalType: Type | undefined;
+                // whether one type contains effective optional chain
+                // This is especially important when narrow condition is equal to undefined, as a result of optional chain.
+                containsEffectiveOptionalChain: boolean;
+            }
+
+            /**
+             * Assume there is variable `foo` whose type is `A`, try to get the final type of foo.property1.proerty2...
+             * @param type Assume this should be just the type of 'reference'
+             * @param expressionWithOutKeyword an expression without any keyword. "typeof root.a" is not acceptable.
+             */
+            function getPropertyTypesFromTypeByBindingElementOrExpression(type: Type, expressionWithOutKeyword: BindingElement | Expression | ParameterDeclaration): NarrowDeepPropertyInfo[] | undefined {
+                interface PathInfo {
+                    path: __String;
+                    isOptionalChain: boolean;
+                }
+
+                let callExpressionFlag = false;
+                if (isCallExpression(expressionWithOutKeyword)) {
+                    callExpressionFlag = true;
+                    expressionWithOutKeyword = expressionWithOutKeyword.expression;
+                }
+
+                const nonCallExpressionWithOutKeyword = expressionWithOutKeyword;
+
+                // check some condition, if not meet, it means we could not handle this confition for now.
+                if (nonCallExpressionWithOutKeyword.kind !== SyntaxKind.Identifier && nonCallExpressionWithOutKeyword.kind !== SyntaxKind.BindingElement && nonCallExpressionWithOutKeyword.kind !== SyntaxKind.Parameter && !isAccessExpression(nonCallExpressionWithOutKeyword)) {// || (<AccessExpression>expressionWithOutKeyword).expression.kind === SyntaxKind.ThisKeyword) {
+                    return undefined;
+                }
+
+                const propertyPaths = tryGetPropertyPathsOfReferenceFromExpression(nonCallExpressionWithOutKeyword, reference);
+                if (!propertyPaths) {
+                    return undefined;
+                }
+
+                // In most case, if sometype in the union type could not reach the path,
+                // it should be an error which is not handled by this function, and we just not continue filter types.
+                // But, we must consider some edge cases, like:
+                // 1. type A is { a: undefined }.
+                // 2. type B is { a: never }.
+                // Now we have `type C = { a: {innerType: 1} }`
+                // for case 1, create `type X = A|C`, it should be filtered through optional chain, and not cause any error, although A.a does not have any inner type. Like `root.a?.innerType` is valid.
+                // for case 2, it is similar, and we do not even need optional chain. Like `root.a.innerType`
+
+                let propertyTypeArray: NarrowDeepPropertyInfo[] | undefined;
+                forEachType(type, t => {
+                    const propType = getPropertyTypeFromTypeAccordingToPath(t, propertyPaths, callExpressionFlag);
+                    if (propType) {
+                        propertyTypeArray = append(propertyTypeArray, propType);
+                    }
+                    else {
+                        propertyTypeArray = undefined;
+                        return true;
+                    }
+                });
+
+                return propertyTypeArray;
+
+                // Assume reference is a
+                // If expression is a, return []
+                // If expression is a.b["c"].d(), return ["b","c","d"]
+                // If element is BindingElement 'const x = a.b.c', return ["b", "c"]
+                // If element is BindingElement 'const { c: x } = a.b', return ["b", "c"]
+                // if element is ParameterDeclaration '(a, b)=>{a.x.y}' return the index of parameters, in this example, returns ["0", "x", "y"]
+                // NOTE: If element expression is not known in compile progress like a.b[f()].d, the result would be undefined
+                // NOTE: Binding element is restricted for now: reference must be more "expanded" than node, which might be a binding element. See this example:
+                // const tmp1 = root.a.b; const { b : tmp2 } = root.a;
+                // if (tmp1.c.d === "A") root.a.b // root would be narrowed
+                // if (root.a.b.c.d === "A") tmp1.c.d // however, tmp1 would not be narrowed for now
+                // The result is similar for tmp2
+                // //NOTE: this function need improvement, ElementAccessExpression argument might could be known in compile time, like "1"+"2", we should check "12" in the path, but how to get the value?
+                function tryGetPropertyPathsOfReferenceFromExpression(node: Expression | BindingElement | ParameterDeclaration, reference: Node): PathInfo[] | undefined {
+                    const properties = [];
+                    let exprOrBindingElement: BindingElement | Expression | ParameterDeclaration | undefined = node;
+                    let access: Expression | undefined;
+
+                    while (exprOrBindingElement && !isMatchingReference(reference, currentNode()) && (isAccessExpression(exprOrBindingElement) || isBindingElement(exprOrBindingElement) || isParameter(exprOrBindingElement))) {
+                        const propName = getAccessedPropertyName(exprOrBindingElement);
+                        if (!propName) {
+                            return undefined;
+                        }
+                        properties.unshift({ path: propName, isOptionalChain: isOptionalChain(exprOrBindingElement) });
+                        // When `exprOrBindingElement` is ParameterDeclaration, we have got all property paths.
+                        // When `exprOrBindingElement` is bindElement, there are two conditions:
+                        // 1. const { bindingElement } = parentObject;
+                        // 2. function foo({ bindingElement }) {...}
+                        // For 1, `access` is `parentObject`
+                        // For 2, we have got all property paths
+                        if (isParameter(exprOrBindingElement) || (isBindingElement(exprOrBindingElement) && !exprOrBindingElement.initializer && !exprOrBindingElement.dotDotDotToken && reference === exprOrBindingElement.parent)) {
+                            return properties;
+                        }
+                        access = isBindingElement(exprOrBindingElement) ? exprOrBindingElement.parent.parent.initializer : exprOrBindingElement.expression;
+                        if (!access) {
+                            return undefined;
+                        }
+                        if (isMatchingReference(reference, access)) {
+                            return properties;
+                        }
+                        exprOrBindingElement = getCandidateDiscriminantPropertyAccess(access);
+                    }
+
+                    if (isMatchingReference(reference, currentNode())) {
+                        return properties;
+                    }
+
+                    function currentNode() {
+                        if (exprOrBindingElement) return exprOrBindingElement;
+                        if (access) return access;
+                        throw new Error("Never");
+                    }
+                }
+
+                function getPropertyTypeFromTypeAccordingToPath(constituentType: Type, pathInfos: PathInfo[], isCallExpression: boolean): NarrowDeepPropertyInfo | undefined {
+                    let propType: Type | undefined = constituentType;
+                    const typeId = constituentType.id;
+                    let containsEffectiveOptionalChain = false;
+                    for (const pathInfo of pathInfos) {
+                        const path = pathInfo.path;
+                        const isEffectiveOptionalChain = strictNullChecks && pathInfo.isOptionalChain && maybeTypeOfKind(propType, TypeFlags.Nullable);
+                        if (isEffectiveOptionalChain) {
+                            containsEffectiveOptionalChain = true;
+                        }
+                        if (propType.flags & TypeFlags.Nullable) {
+                            return { typeId, finalType: undefined, containsEffectiveOptionalChain };
+                        }
+                        const nonNullableTypeIfStrict = getNonNullableTypeIfNeeded(propType);
+                        if (nonNullableTypeIfStrict.flags & TypeFlags.UnionOrIntersection) {
+                            // although getTypeOfPropertyOfType use getPropertyOfUnionOrIntersectionType, but in getReducedApparentType
+                            // intersection type that contains mutually exclusive discriminant properties returns never.
+                            const prop = getPropertyOfUnionOrIntersectionType(nonNullableTypeIfStrict as UnionOrIntersectionType, path);
+                            propType = prop && getTypeOfSymbol(prop); // unknownType is to keep coninstance with the return value of getTypeOfPropertyOrIndexSignature
+                        }
+                        else {
+                            propType = getTypeOfPropertyOrIndexSignature(nonNullableTypeIfStrict, path);
+                        }
+
+                        if (!propType) {
+                            return undefined;
+                        }
+                    }
+
+                    // here could be improved, now, we access all return type for the signature, but it could use parameter to get reduced return types.
+                    if (isCallExpression && propType && propType.flags & TypeFlags.Object) {
+                        const returnTypes = (propType as ObjectType).callSignatures?.map(getReturnTypeOfSignature);
+                        return returnTypes && {
+                            typeId,
+                            finalType: getUnionType(returnTypes),
+                            containsEffectiveOptionalChain
+                        };
+                    }
+
+                    return {
+                        typeId,
+                        finalType: propType,
+                        containsEffectiveOptionalChain
+                    };
+                }
+            }
+
             function narrowTypeByTypeof(type: Type, typeOfExpr: TypeOfExpression, operator: SyntaxKind, literal: LiteralExpression, assumeTrue: boolean): Type {
                 // We have '==', '!=', '===', or !==' operator with 'typeof xxx' and string literal operands
                 if (operator === SyntaxKind.ExclamationEqualsToken || operator === SyntaxKind.ExclamationEqualsEqualsToken) {
                     assumeTrue = !assumeTrue;
                 }
+                const facts = assumeTrue ?
+                typeofEQFacts.get(literal.text) || TypeFacts.TypeofEQHostObject :
+                typeofNEFacts.get(literal.text) || TypeFacts.TypeofNEHostObject;
                 const target = getReferenceCandidate(typeOfExpr.expression);
                 if (!isMatchingReference(reference, target)) {
-                    if (strictNullChecks && optionalChainContainsReference(target, reference) && assumeTrue === (literal.text !== "undefined")) {
-                        return getTypeWithFacts(type, TypeFacts.NEUndefinedOrNull);
+                    if (type.flags & TypeFlags.Union) {
+                        const propertyTypes = getPropertyTypesFromTypeByBindingElementOrExpression(type as UnionType, typeOfExpr.expression);
+                        const impliedUndefined = (assumeTrue && literal.text === "undefined") || (!assumeTrue && literal.text !== "undefined");
+                        if (!propertyTypes) {
+                            return type;
+                        }
+                        const markSet = new Set<TypeId>();
+
+                        propertyTypes.forEach(propertyType => {
+                            if (!propertyType.finalType && !propertyType.containsEffectiveOptionalChain) {
+                                return;
+                            }
+                            const reachableFinalType = propertyType.finalType;
+                            if (propertyType.containsEffectiveOptionalChain && impliedUndefined) {
+                                markSet.add(propertyType.typeId);
+                            }
+                            else if (!!reachableFinalType) {
+                                const propertyTypeFacts = getTypeFacts(reachableFinalType);
+                                if ((propertyTypeFacts & facts) === facts) {
+                                    markSet.add(propertyType.typeId);
+                                }
+                            }
+                        });
+                        return filterType(type, (t) => markSet.has(t.id));
                     }
                     return type;
                 }
+
+                // following code is all for typeof expression.
                 if (type.flags & TypeFlags.Any && literal.text === "function") {
                     return type;
                 }
@@ -24478,9 +24725,6 @@ namespace ts {
                     // unknown type, and then narrows that to the non-primitive type.
                     return type === nonNullUnknownType ? nonPrimitiveType : getUnionType([nonPrimitiveType, nullType]);
                 }
-                const facts = assumeTrue ?
-                    typeofEQFacts.get(literal.text) || TypeFacts.TypeofEQHostObject :
-                    typeofNEFacts.get(literal.text) || TypeFacts.TypeofNEHostObject;
                 const impliedType = getImpliedTypeFromTypeofGuard(type, literal.text);
                 return getTypeWithFacts(assumeTrue && impliedType ? mapType(type, narrowUnionMemberByTypeof(impliedType)) : type, facts);
             }
@@ -24593,9 +24837,6 @@ namespace ts {
                     clauseWitnesses = switchWitnesses.slice(clauseStart, clauseEnd) as string[];
                     switchFacts = getFactsFromTypeofSwitch(clauseStart, clauseEnd, switchWitnesses as string[], hasDefaultClause);
                 }
-                if (hasDefaultClause) {
-                    return filterType(type, t => (getTypeFacts(t) & switchFacts) === switchFacts);
-                }
                 /*
                   The implied type is the raw type suggested by a
                   value being caught in this clause.
@@ -24624,8 +24865,38 @@ namespace ts {
                   boolean. We know that number cannot be selected
                   because it is caught in the first clause.
                 */
+                const expr = (switchStatement.expression as TypeOfExpression).expression;
                 const impliedType = getTypeWithFacts(getUnionType(clauseWitnesses.map(text => getImpliedTypeFromTypeofGuard(type, text) || type)), switchFacts);
-                return getTypeWithFacts(mapType(type, narrowUnionMemberByTypeof(impliedType)), switchFacts);
+                if (isMatchingReference(reference, expr)) {
+                    if (hasDefaultClause) {
+                        return filterType(type, t => (getTypeFacts(t) & switchFacts) === switchFacts);
+                    }
+                    return getTypeWithFacts(mapType(type, narrowUnionMemberByTypeof(impliedType)), switchFacts);
+                }
+                const impliedUndefined = hasDefaultClause ? !(switchFacts & TypeFacts.NEUndefined) : (switchFacts & TypeFacts.EQUndefined);
+                const propertyTypeArray = getPropertyTypesFromTypeByBindingElementOrExpression(type as UnionType, expr);
+
+                if (!propertyTypeArray) {
+                    return type;
+                }
+                const markSet = new Set<TypeId>();
+
+                propertyTypeArray.forEach(propertyType => {
+                    if (!propertyType.finalType && !propertyType.containsEffectiveOptionalChain) {
+                        return;
+                    }
+                    const reachableFinalType = propertyType.finalType;
+                    if (propertyType.containsEffectiveOptionalChain && impliedUndefined) {
+                        markSet.add(propertyType.typeId);
+                    }
+                    else if (!!reachableFinalType) {
+                        const propertyTypeFacts = getTypeFacts(reachableFinalType);
+                        if (!hasDefaultClause ? propertyTypeFacts & switchFacts : ((propertyTypeFacts & switchFacts) === switchFacts)) {
+                            markSet.add(propertyType.typeId);
+                        }
+                    }
+                });
+                return filterType(type, (t) => markSet.has(t.id));
             }
 
             function isMatchingConstructorReference(expr: Expression) {
@@ -24798,8 +25069,7 @@ namespace ts {
             // will be a subtype or the same type as the argument.
             function narrowType(type: Type, expr: Expression, assumeTrue: boolean): Type {
                 // for `a?.b`, we emulate a synthetic `a !== null && a !== undefined` condition for `a`
-                if (isExpressionOfOptionalChainRoot(expr) ||
-                    isBinaryExpression(expr.parent) && expr.parent.operatorToken.kind === SyntaxKind.QuestionQuestionToken && expr.parent.left === expr) {
+                if (isExpressionOfOptionalChainRoot(expr) || isInQuestionQuestionTokenBranch(expr)) {
                     return narrowTypeByOptionality(type, expr, assumeTrue);
                 }
                 switch (expr.kind) {
@@ -24840,6 +25110,27 @@ namespace ts {
                 return type;
             }
 
+            function isInQuestionQuestionTokenBranch(expression: Expression) {
+                let outAccessExpression = expression;
+                let depth = 0;
+                let lastExpression;
+                do {
+                    depth = depth + 1;
+                    lastExpression = outAccessExpression;
+                    if (!isExpression(outAccessExpression.parent)) {// or isExpressionNode? which one should be used?
+                        return false;
+                    }
+                    outAccessExpression = outAccessExpression.parent;
+                }
+                while (isAccessExpression(outAccessExpression));
+                const isQuestionQuestionTokenExpression = isBinaryExpression(outAccessExpression) && outAccessExpression.operatorToken.kind === SyntaxKind.QuestionQuestionToken;
+                if (!isQuestionQuestionTokenExpression) {
+                    return false;
+                }
+                const isExpressOnLeft = (outAccessExpression as BinaryExpression).left === lastExpression;
+                return isQuestionQuestionTokenExpression && isExpressOnLeft;
+            }
+
             function narrowTypeByOptionality(type: Type, expr: Expression, assumePresent: boolean): Type {
                 if (isMatchingReference(reference, expr)) {
                     return getTypeWithFacts(type, assumePresent ? TypeFacts.NEUndefinedOrNull : TypeFacts.EQUndefinedOrNull);
@@ -33978,6 +34269,7 @@ namespace ts {
                 return quickType;
             }
             // If a type has been cached for the node, return it.
+            // Note: this is not only cache, without this, some test case would keep running, such as binaryArithmeticControlFlowGraphNotTooLarge.
             if (node.flags & NodeFlags.TypeCached && flowTypeCache) {
                 const cachedType = flowTypeCache[getNodeId(node)];
                 if (cachedType) {
@@ -40150,8 +40442,8 @@ namespace ts {
                 // If we hit an export assignment in an illegal context, just bail out to avoid cascading errors.
                 return;
             }
-
-            const container = node.parent.kind === SyntaxKind.SourceFile ? node.parent : node.parent.parent as ModuleDeclaration;
+            // use any to avoid type narrow
+            const container = (node.parent as any).kind === SyntaxKind.SourceFile ? node.parent : node.parent.parent as ModuleDeclaration;
             if (container.kind === SyntaxKind.ModuleDeclaration && !isAmbientModule(container)) {
                 if (node.isExportEquals) {
                     error(node, Diagnostics.An_export_assignment_cannot_be_used_in_a_namespace);
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index 48ac670c8bea3..38729c172126c 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -1283,8 +1283,8 @@ namespace ts {
 
             const platform: string = _os.platform();
             const useCaseSensitiveFileNames = isFileSystemCaseSensitive();
-            const realpathSync = _fs.realpathSync.native ?? _fs.realpathSync;
-
+            // Use `any` to avoid type narrow.
+            const realpathSync = (_fs as any).realpathSync.native ?? _fs.realpathSync;
             const fsSupportsRecursiveFsWatch = isNode4OrLater && (process.platform === "win32" || process.platform === "darwin");
             const getCurrentDirectory = memoize(() => process.cwd());
             const { watchFile, watchDirectory } = createSystemWatchFunctions({
diff --git a/src/server/session.ts b/src/server/session.ts
index b0bb42dade1ca..fcd1aef197604 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -1516,7 +1516,8 @@ namespace ts.server {
             // filter handles case when 'projects' is undefined
             projects = filter(projects, p => p.languageServiceEnabled && !p.isOrphan());
             if (!ignoreNoProjectError && (!projects || !projects.length) && !symLinkedProjects) {
-                this.projectService.logErrorForScriptInfoNotFound(args.file ?? args.projectFileName);
+                // use `any` to avoid type narrow
+                this.projectService.logErrorForScriptInfoNotFound((args as any).file ?? args.projectFileName);
                 return Errors.ThrowNoProject();
             }
             return symLinkedProjects ? { projects: projects!, symLinkedProjects } : projects!; // TODO: GH#18217
diff --git a/tests/baselines/reference/controlFlowOptionalChain.errors.txt b/tests/baselines/reference/controlFlowOptionalChain.errors.txt
index 1dfe8e9e328a0..17fbb84f7d7e2 100644
--- a/tests/baselines/reference/controlFlowOptionalChain.errors.txt
+++ b/tests/baselines/reference/controlFlowOptionalChain.errors.txt
@@ -57,11 +57,10 @@ tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(463,9): error TS
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(498,13): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(501,13): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(515,13): error TS2532: Object is possibly 'undefined'.
-tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(518,13): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(567,21): error TS2532: Object is possibly 'undefined'.
 
 
-==== tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts (61 errors) ====
+==== tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts (60 errors) ====
     // assignments in shortcutting chain
     declare const o: undefined | {
         [key: string]: any;
@@ -697,9 +696,7 @@ tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(567,21): error T
 !!! error TS2532: Object is possibly 'undefined'.
                 break;
             default:
-                o.foo;  // Error
-                ~
-!!! error TS2532: Object is possibly 'undefined'.
+                o.foo;
                 break;
         }
     }
diff --git a/tests/baselines/reference/controlFlowOptionalChain.js b/tests/baselines/reference/controlFlowOptionalChain.js
index dc2361d860984..25386b69c2746 100644
--- a/tests/baselines/reference/controlFlowOptionalChain.js
+++ b/tests/baselines/reference/controlFlowOptionalChain.js
@@ -516,7 +516,7 @@ function f41(o: Thing | undefined) {
             o.foo;  // Error
             break;
         default:
-            o.foo;  // Error
+            o.foo;
             break;
     }
 }
@@ -1049,7 +1049,7 @@ function f41(o) {
             o.foo; // Error
             break;
         default:
-            o.foo; // Error
+            o.foo;
             break;
     }
 }
diff --git a/tests/baselines/reference/controlFlowOptionalChain.symbols b/tests/baselines/reference/controlFlowOptionalChain.symbols
index be03f36c67da6..5e1f91aafd56f 100644
--- a/tests/baselines/reference/controlFlowOptionalChain.symbols
+++ b/tests/baselines/reference/controlFlowOptionalChain.symbols
@@ -1438,9 +1438,7 @@ function f23(o: Thing | undefined) {
 >foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
 
         o.foo;  // Error
->o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
 >o : Symbol(o, Decl(controlFlowOptionalChain.ts, 439, 13))
->foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
     }
     else {
         o.foo;
@@ -1460,9 +1458,7 @@ function f23(o: Thing | undefined) {
     }
     else {
         o.foo;  // Error
->o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
 >o : Symbol(o, Decl(controlFlowOptionalChain.ts, 439, 13))
->foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
     }
     if (typeof o?.foo == "undefined") {
 >o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
@@ -1470,9 +1466,7 @@ function f23(o: Thing | undefined) {
 >foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
 
         o.foo;  // Error
->o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
 >o : Symbol(o, Decl(controlFlowOptionalChain.ts, 439, 13))
->foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
     }
     else {
         o.foo;
@@ -1492,9 +1486,7 @@ function f23(o: Thing | undefined) {
     }
     else {
         o.foo;  // Error
->o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
 >o : Symbol(o, Decl(controlFlowOptionalChain.ts, 439, 13))
->foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
     }
 }
 
@@ -1636,13 +1628,11 @@ function f41(o: Thing | undefined) {
             break;
         case "undefined":
             o.foo;  // Error
->o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
 >o : Symbol(o, Decl(controlFlowOptionalChain.ts, 505, 13))
->foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
 
             break;
         default:
-            o.foo;  // Error
+            o.foo;
 >o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
 >o : Symbol(o, Decl(controlFlowOptionalChain.ts, 505, 13))
 >foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
diff --git a/tests/baselines/reference/controlFlowOptionalChain.types b/tests/baselines/reference/controlFlowOptionalChain.types
index 4e335fca6d287..9b404b7a02c26 100644
--- a/tests/baselines/reference/controlFlowOptionalChain.types
+++ b/tests/baselines/reference/controlFlowOptionalChain.types
@@ -1618,9 +1618,9 @@ function f23(o: Thing | undefined) {
 >"undefined" : "undefined"
 
         o.foo;  // Error
->o.foo : never
->o : Thing | undefined
->foo : never
+>o.foo : any
+>o : undefined
+>foo : any
     }
     else {
         o.foo;
@@ -1643,9 +1643,9 @@ function f23(o: Thing | undefined) {
     }
     else {
         o.foo;  // Error
->o.foo : never
->o : Thing | undefined
->foo : never
+>o.foo : any
+>o : undefined
+>foo : any
     }
     if (typeof o?.foo == "undefined") {
 >typeof o?.foo == "undefined" : boolean
@@ -1656,9 +1656,9 @@ function f23(o: Thing | undefined) {
 >"undefined" : "undefined"
 
         o.foo;  // Error
->o.foo : never
->o : Thing | undefined
->foo : never
+>o.foo : any
+>o : undefined
+>foo : any
     }
     else {
         o.foo;
@@ -1681,9 +1681,9 @@ function f23(o: Thing | undefined) {
     }
     else {
         o.foo;  // Error
->o.foo : never
->o : Thing | undefined
->foo : never
+>o.foo : any
+>o : undefined
+>foo : any
     }
 }
 
@@ -1852,15 +1852,15 @@ function f41(o: Thing | undefined) {
 >"undefined" : "undefined"
 
             o.foo;  // Error
->o.foo : never
->o : Thing | undefined
->foo : never
+>o.foo : any
+>o : undefined
+>foo : any
 
             break;
         default:
-            o.foo;  // Error
+            o.foo;
 >o.foo : never
->o : Thing | undefined
+>o : Thing
 >foo : never
 
             break;
diff --git a/tests/baselines/reference/destructuringControlFlow.types b/tests/baselines/reference/destructuringControlFlow.types
index 02deb39200688..a9852433f239d 100644
--- a/tests/baselines/reference/destructuringControlFlow.types
+++ b/tests/baselines/reference/destructuringControlFlow.types
@@ -63,34 +63,34 @@ function f2(obj: [number, string] | null[]) {
 >obj[0] : number | null
 >obj : [number, string] | null[]
 >0 : 0
->obj[1] : string | null
->obj : [number, string] | null[]
+>obj[1] : string
+>obj : [number, string]
 >1 : 1
 
         let c0 = obj[0];  // number
 >c0 : number
 >obj[0] : number
->obj : [number, string] | null[]
+>obj : [number, string]
 >0 : 0
 
         let c1 = obj[1];  // string
 >c1 : string
 >obj[1] : string
->obj : [number, string] | null[]
+>obj : [number, string]
 >1 : 1
 
         let [d0, d1] = obj;
 >d0 : number
 >d1 : string
->obj : [number, string] | null[]
+>obj : [number, string]
 
         ([c0, c1] = obj);
->([c0, c1] = obj) : [number, string] | null[]
->[c0, c1] = obj : [number, string] | null[]
+>([c0, c1] = obj) : [number, string]
+>[c0, c1] = obj : [number, string]
 >[c0, c1] : [number, string]
 >c0 : number
 >c1 : string
->obj : [number, string] | null[]
+>obj : [number, string]
     }
 }
 
diff --git a/tests/baselines/reference/discriminatedUnionTypes2.errors.txt b/tests/baselines/reference/discriminatedUnionTypes2.errors.txt
index f2ced8d19fa6c..0cb87c1aa5931 100644
--- a/tests/baselines/reference/discriminatedUnionTypes2.errors.txt
+++ b/tests/baselines/reference/discriminatedUnionTypes2.errors.txt
@@ -2,9 +2,10 @@ tests/cases/conformance/types/union/discriminatedUnionTypes2.ts(27,30): error TS
   Object literal may only specify known properties, and 'c' does not exist in type '{ a: null; b: string; }'.
 tests/cases/conformance/types/union/discriminatedUnionTypes2.ts(32,11): error TS2339: Property 'b' does not exist on type '{ a: 0; b: string; } | { a: T; c: number; }'.
   Property 'b' does not exist on type '{ a: T; c: number; }'.
+tests/cases/conformance/types/union/discriminatedUnionTypes2.ts(132,11): error TS2339: Property 'value' does not exist on type 'never'.
 
 
-==== tests/cases/conformance/types/union/discriminatedUnionTypes2.ts (2 errors) ====
+==== tests/cases/conformance/types/union/discriminatedUnionTypes2.ts (3 errors) ====
     function f10(x : { kind: false, a: string } | { kind: true, b: string } | { kind: string, c: string }) {
         if (x.kind === false) {
             x.a;
@@ -142,7 +143,9 @@ tests/cases/conformance/types/union/discriminatedUnionTypes2.ts(32,11): error TS
             x.value;  // number
         }
         else {
-            x.value;  // number
+            x.value;  // Error, x is never
+              ~~~~~
+!!! error TS2339: Property 'value' does not exist on type 'never'.
         }
     }
     
diff --git a/tests/baselines/reference/discriminatedUnionTypes2.js b/tests/baselines/reference/discriminatedUnionTypes2.js
index b94c386b4699e..584678ee7fa53 100644
--- a/tests/baselines/reference/discriminatedUnionTypes2.js
+++ b/tests/baselines/reference/discriminatedUnionTypes2.js
@@ -130,7 +130,7 @@ function foo1(x: RuntimeValue & { type: 'number' }) {
         x.value;  // number
     }
     else {
-        x.value;  // number
+        x.value;  // Error, x is never
     }
 }
 
@@ -226,7 +226,7 @@ function foo1(x) {
         x.value; // number
     }
     else {
-        x.value; // number
+        x.value; // Error, x is never
     }
 }
 function foo2(x) {
diff --git a/tests/baselines/reference/discriminatedUnionTypes2.symbols b/tests/baselines/reference/discriminatedUnionTypes2.symbols
index 747f43ac21e4c..f2a511b6d23dc 100644
--- a/tests/baselines/reference/discriminatedUnionTypes2.symbols
+++ b/tests/baselines/reference/discriminatedUnionTypes2.symbols
@@ -366,10 +366,8 @@ function foo1(x: RuntimeValue & { type: 'number' }) {
 >value : Symbol(value, Decl(discriminatedUnionTypes2.ts, 122, 23))
     }
     else {
-        x.value;  // number
->x.value : Symbol(value, Decl(discriminatedUnionTypes2.ts, 122, 23))
+        x.value;  // Error, x is never
 >x : Symbol(x, Decl(discriminatedUnionTypes2.ts, 126, 14))
->value : Symbol(value, Decl(discriminatedUnionTypes2.ts, 122, 23))
     }
 }
 
diff --git a/tests/baselines/reference/discriminatedUnionTypes2.types b/tests/baselines/reference/discriminatedUnionTypes2.types
index 695f0c3768f00..285c4dd4a6839 100644
--- a/tests/baselines/reference/discriminatedUnionTypes2.types
+++ b/tests/baselines/reference/discriminatedUnionTypes2.types
@@ -379,10 +379,10 @@ function foo1(x: RuntimeValue & { type: 'number' }) {
 >value : number
     }
     else {
-        x.value;  // number
->x.value : number
->x : { type: "number"; value: number; } & { type: "number"; }
->value : number
+        x.value;  // Error, x is never
+>x.value : any
+>x : never
+>value : any
     }
 }
 
diff --git a/tests/baselines/reference/discriminatedUnionTypes3.errors.txt b/tests/baselines/reference/discriminatedUnionTypes3.errors.txt
new file mode 100644
index 0000000000000..6d365202ad06a
--- /dev/null
+++ b/tests/baselines/reference/discriminatedUnionTypes3.errors.txt
@@ -0,0 +1,91 @@
+tests/cases/conformance/types/union/discriminatedUnionTypes3.ts(59,11): error TS2339: Property 's' does not exist on type 'T'.
+tests/cases/conformance/types/union/discriminatedUnionTypes3.ts(78,10): error TS2339: Property 'property' does not exist on type 'SomeReturnType'.
+  Property 'property' does not exist on type 'Err'.
+
+
+==== tests/cases/conformance/types/union/discriminatedUnionTypes3.ts (2 errors) ====
+    type A = { type2: "a", a: number }
+    type B = { type2: "b", b: number }
+    type C = { type2: "c", b: number | string }
+    
+    type X = { type1: A, x: string }
+    type Y = { type1: B, y: string }
+    type Z = { type1: C, z: string }
+    type W = { type1: undefined }
+    
+    function f32(x: X | Y) {
+        switch (x.type1.type2) {
+            case "a":
+                x.x // typeof x is X
+                break;
+            case "b":
+                x.y // typeof x is Y
+                break;
+        }
+    }
+    
+    function f33(x: A | B) {
+        switch (x.type2) {
+            case "a":
+                x // typeof x is X
+                break;
+            case "b":
+                x // typeof x is Y
+                break;
+        }
+    }
+    
+    function f34(x: X | Y) {
+        if (x.type1.type2 === "a") {
+            x.x // typeof x is X
+        } else if (x.type1.type2 === "b") {
+            x.y // typeof x is Y
+        }
+    }
+    
+    function f35(x: X | W) {
+        if (x.type1?.type2 === "a") {
+            x.x
+        }
+    }
+    
+    function f36(x: X | W) {
+        x.type1?.type2 ?? x;
+    }
+    
+    type S = { sub: { type0: X }, s: string }
+    type T = { sub: { type0: Y }, t: string }
+    
+    function f37(s: S | T) {
+        if (s.sub.type0.type1.type2 === "a") {
+            s.s // typeof s is S
+            s.sub.type0.x // type of s.sub.type is X
+            s.sub.type0.type1.a // type of s.sub.type.type is A
+        } else {
+            s.s // type error!
+              ~
+!!! error TS2339: Property 's' does not exist on type 'T'.
+        }
+    }
+    
+    // Repro from #44435
+    
+    type Correct = {
+    	code: string
+    	property: true
+    	err: undefined
+    }
+    type Err = {
+    	err: `${string} is wrong!`
+    }
+    type SomeReturnType = Correct | Err;
+    
+    const example: SomeReturnType = {} as SomeReturnType;
+    
+    if (example.err === undefined) {
+    	example.property;  // true
+    	        ~~~~~~~~
+!!! error TS2339: Property 'property' does not exist on type 'SomeReturnType'.
+!!! error TS2339:   Property 'property' does not exist on type 'Err'.
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/discriminatedUnionTypes3.js b/tests/baselines/reference/discriminatedUnionTypes3.js
index 74edcd85ac0be..92a940be65141 100644
--- a/tests/baselines/reference/discriminatedUnionTypes3.js
+++ b/tests/baselines/reference/discriminatedUnionTypes3.js
@@ -1,4 +1,66 @@
 //// [discriminatedUnionTypes3.ts]
+type A = { type2: "a", a: number }
+type B = { type2: "b", b: number }
+type C = { type2: "c", b: number | string }
+
+type X = { type1: A, x: string }
+type Y = { type1: B, y: string }
+type Z = { type1: C, z: string }
+type W = { type1: undefined }
+
+function f32(x: X | Y) {
+    switch (x.type1.type2) {
+        case "a":
+            x.x // typeof x is X
+            break;
+        case "b":
+            x.y // typeof x is Y
+            break;
+    }
+}
+
+function f33(x: A | B) {
+    switch (x.type2) {
+        case "a":
+            x // typeof x is X
+            break;
+        case "b":
+            x // typeof x is Y
+            break;
+    }
+}
+
+function f34(x: X | Y) {
+    if (x.type1.type2 === "a") {
+        x.x // typeof x is X
+    } else if (x.type1.type2 === "b") {
+        x.y // typeof x is Y
+    }
+}
+
+function f35(x: X | W) {
+    if (x.type1?.type2 === "a") {
+        x.x
+    }
+}
+
+function f36(x: X | W) {
+    x.type1?.type2 ?? x;
+}
+
+type S = { sub: { type0: X }, s: string }
+type T = { sub: { type0: Y }, t: string }
+
+function f37(s: S | T) {
+    if (s.sub.type0.type1.type2 === "a") {
+        s.s // typeof s is S
+        s.sub.type0.x // type of s.sub.type is X
+        s.sub.type0.type1.a // type of s.sub.type.type is A
+    } else {
+        s.s // type error!
+    }
+}
+
 // Repro from #44435
 
 type Correct = {
@@ -15,11 +77,59 @@ const example: SomeReturnType = {} as SomeReturnType;
 
 if (example.err === undefined) {
 	example.property;  // true
-}
+}
+
 
 //// [discriminatedUnionTypes3.js]
 "use strict";
-// Repro from #44435
+function f32(x) {
+    switch (x.type1.type2) {
+        case "a":
+            x.x; // typeof x is X
+            break;
+        case "b":
+            x.y; // typeof x is Y
+            break;
+    }
+}
+function f33(x) {
+    switch (x.type2) {
+        case "a":
+            x; // typeof x is X
+            break;
+        case "b":
+            x; // typeof x is Y
+            break;
+    }
+}
+function f34(x) {
+    if (x.type1.type2 === "a") {
+        x.x; // typeof x is X
+    }
+    else if (x.type1.type2 === "b") {
+        x.y; // typeof x is Y
+    }
+}
+function f35(x) {
+    var _a;
+    if (((_a = x.type1) === null || _a === void 0 ? void 0 : _a.type2) === "a") {
+        x.x;
+    }
+}
+function f36(x) {
+    var _a, _b;
+    (_b = (_a = x.type1) === null || _a === void 0 ? void 0 : _a.type2) !== null && _b !== void 0 ? _b : x;
+}
+function f37(s) {
+    if (s.sub.type0.type1.type2 === "a") {
+        s.s; // typeof s is S
+        s.sub.type0.x; // type of s.sub.type is X
+        s.sub.type0.type1.a; // type of s.sub.type.type is A
+    }
+    else {
+        s.s; // type error!
+    }
+}
 var example = {};
 if (example.err === undefined) {
     example.property; // true
diff --git a/tests/baselines/reference/discriminatedUnionTypes3.symbols b/tests/baselines/reference/discriminatedUnionTypes3.symbols
index 65fdd49877055..b88fb150d6e81 100644
--- a/tests/baselines/reference/discriminatedUnionTypes3.symbols
+++ b/tests/baselines/reference/discriminatedUnionTypes3.symbols
@@ -1,42 +1,261 @@
 === tests/cases/conformance/types/union/discriminatedUnionTypes3.ts ===
+type A = { type2: "a", a: number }
+>A : Symbol(A, Decl(discriminatedUnionTypes3.ts, 0, 0))
+>type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10))
+>a : Symbol(a, Decl(discriminatedUnionTypes3.ts, 0, 22))
+
+type B = { type2: "b", b: number }
+>B : Symbol(B, Decl(discriminatedUnionTypes3.ts, 0, 34))
+>type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 1, 10))
+>b : Symbol(b, Decl(discriminatedUnionTypes3.ts, 1, 22))
+
+type C = { type2: "c", b: number | string }
+>C : Symbol(C, Decl(discriminatedUnionTypes3.ts, 1, 34))
+>type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 2, 10))
+>b : Symbol(b, Decl(discriminatedUnionTypes3.ts, 2, 22))
+
+type X = { type1: A, x: string }
+>X : Symbol(X, Decl(discriminatedUnionTypes3.ts, 2, 43))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10))
+>A : Symbol(A, Decl(discriminatedUnionTypes3.ts, 0, 0))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 4, 20))
+
+type Y = { type1: B, y: string }
+>Y : Symbol(Y, Decl(discriminatedUnionTypes3.ts, 4, 32))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 5, 10))
+>B : Symbol(B, Decl(discriminatedUnionTypes3.ts, 0, 34))
+>y : Symbol(y, Decl(discriminatedUnionTypes3.ts, 5, 20))
+
+type Z = { type1: C, z: string }
+>Z : Symbol(Z, Decl(discriminatedUnionTypes3.ts, 5, 32))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 6, 10))
+>C : Symbol(C, Decl(discriminatedUnionTypes3.ts, 1, 34))
+>z : Symbol(z, Decl(discriminatedUnionTypes3.ts, 6, 20))
+
+type W = { type1: undefined }
+>W : Symbol(W, Decl(discriminatedUnionTypes3.ts, 6, 32))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 7, 10))
+
+function f32(x: X | Y) {
+>f32 : Symbol(f32, Decl(discriminatedUnionTypes3.ts, 7, 29))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 9, 13))
+>X : Symbol(X, Decl(discriminatedUnionTypes3.ts, 2, 43))
+>Y : Symbol(Y, Decl(discriminatedUnionTypes3.ts, 4, 32))
+
+    switch (x.type1.type2) {
+>x.type1.type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10), Decl(discriminatedUnionTypes3.ts, 1, 10))
+>x.type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10), Decl(discriminatedUnionTypes3.ts, 5, 10))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 9, 13))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10), Decl(discriminatedUnionTypes3.ts, 5, 10))
+>type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10), Decl(discriminatedUnionTypes3.ts, 1, 10))
+
+        case "a":
+            x.x // typeof x is X
+>x.x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 4, 20))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 9, 13))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 4, 20))
+
+            break;
+        case "b":
+            x.y // typeof x is Y
+>x.y : Symbol(y, Decl(discriminatedUnionTypes3.ts, 5, 20))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 9, 13))
+>y : Symbol(y, Decl(discriminatedUnionTypes3.ts, 5, 20))
+
+            break;
+    }
+}
+
+function f33(x: A | B) {
+>f33 : Symbol(f33, Decl(discriminatedUnionTypes3.ts, 18, 1))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 20, 13))
+>A : Symbol(A, Decl(discriminatedUnionTypes3.ts, 0, 0))
+>B : Symbol(B, Decl(discriminatedUnionTypes3.ts, 0, 34))
+
+    switch (x.type2) {
+>x.type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10), Decl(discriminatedUnionTypes3.ts, 1, 10))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 20, 13))
+>type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10), Decl(discriminatedUnionTypes3.ts, 1, 10))
+
+        case "a":
+            x // typeof x is X
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 20, 13))
+
+            break;
+        case "b":
+            x // typeof x is Y
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 20, 13))
+
+            break;
+    }
+}
+
+function f34(x: X | Y) {
+>f34 : Symbol(f34, Decl(discriminatedUnionTypes3.ts, 29, 1))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 31, 13))
+>X : Symbol(X, Decl(discriminatedUnionTypes3.ts, 2, 43))
+>Y : Symbol(Y, Decl(discriminatedUnionTypes3.ts, 4, 32))
+
+    if (x.type1.type2 === "a") {
+>x.type1.type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10), Decl(discriminatedUnionTypes3.ts, 1, 10))
+>x.type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10), Decl(discriminatedUnionTypes3.ts, 5, 10))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 31, 13))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10), Decl(discriminatedUnionTypes3.ts, 5, 10))
+>type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10), Decl(discriminatedUnionTypes3.ts, 1, 10))
+
+        x.x // typeof x is X
+>x.x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 4, 20))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 31, 13))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 4, 20))
+
+    } else if (x.type1.type2 === "b") {
+>x.type1.type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 1, 10))
+>x.type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 5, 10))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 31, 13))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 5, 10))
+>type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 1, 10))
+
+        x.y // typeof x is Y
+>x.y : Symbol(y, Decl(discriminatedUnionTypes3.ts, 5, 20))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 31, 13))
+>y : Symbol(y, Decl(discriminatedUnionTypes3.ts, 5, 20))
+    }
+}
+
+function f35(x: X | W) {
+>f35 : Symbol(f35, Decl(discriminatedUnionTypes3.ts, 37, 1))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 39, 13))
+>X : Symbol(X, Decl(discriminatedUnionTypes3.ts, 2, 43))
+>W : Symbol(W, Decl(discriminatedUnionTypes3.ts, 6, 32))
+
+    if (x.type1?.type2 === "a") {
+>x.type1?.type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10))
+>x.type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10), Decl(discriminatedUnionTypes3.ts, 7, 10))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 39, 13))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10), Decl(discriminatedUnionTypes3.ts, 7, 10))
+>type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10))
+
+        x.x
+>x.x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 4, 20))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 39, 13))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 4, 20))
+    }
+}
+
+function f36(x: X | W) {
+>f36 : Symbol(f36, Decl(discriminatedUnionTypes3.ts, 43, 1))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 45, 13))
+>X : Symbol(X, Decl(discriminatedUnionTypes3.ts, 2, 43))
+>W : Symbol(W, Decl(discriminatedUnionTypes3.ts, 6, 32))
+
+    x.type1?.type2 ?? x;
+>x.type1?.type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10))
+>x.type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10), Decl(discriminatedUnionTypes3.ts, 7, 10))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 45, 13))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10), Decl(discriminatedUnionTypes3.ts, 7, 10))
+>type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 45, 13))
+}
+
+type S = { sub: { type0: X }, s: string }
+>S : Symbol(S, Decl(discriminatedUnionTypes3.ts, 47, 1))
+>sub : Symbol(sub, Decl(discriminatedUnionTypes3.ts, 49, 10))
+>type0 : Symbol(type0, Decl(discriminatedUnionTypes3.ts, 49, 17))
+>X : Symbol(X, Decl(discriminatedUnionTypes3.ts, 2, 43))
+>s : Symbol(s, Decl(discriminatedUnionTypes3.ts, 49, 29))
+
+type T = { sub: { type0: Y }, t: string }
+>T : Symbol(T, Decl(discriminatedUnionTypes3.ts, 49, 41))
+>sub : Symbol(sub, Decl(discriminatedUnionTypes3.ts, 50, 10))
+>type0 : Symbol(type0, Decl(discriminatedUnionTypes3.ts, 50, 17))
+>Y : Symbol(Y, Decl(discriminatedUnionTypes3.ts, 4, 32))
+>t : Symbol(t, Decl(discriminatedUnionTypes3.ts, 50, 29))
+
+function f37(s: S | T) {
+>f37 : Symbol(f37, Decl(discriminatedUnionTypes3.ts, 50, 41))
+>s : Symbol(s, Decl(discriminatedUnionTypes3.ts, 52, 13))
+>S : Symbol(S, Decl(discriminatedUnionTypes3.ts, 47, 1))
+>T : Symbol(T, Decl(discriminatedUnionTypes3.ts, 49, 41))
+
+    if (s.sub.type0.type1.type2 === "a") {
+>s.sub.type0.type1.type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10), Decl(discriminatedUnionTypes3.ts, 1, 10))
+>s.sub.type0.type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10), Decl(discriminatedUnionTypes3.ts, 5, 10))
+>s.sub.type0 : Symbol(type0, Decl(discriminatedUnionTypes3.ts, 49, 17), Decl(discriminatedUnionTypes3.ts, 50, 17))
+>s.sub : Symbol(sub, Decl(discriminatedUnionTypes3.ts, 49, 10), Decl(discriminatedUnionTypes3.ts, 50, 10))
+>s : Symbol(s, Decl(discriminatedUnionTypes3.ts, 52, 13))
+>sub : Symbol(sub, Decl(discriminatedUnionTypes3.ts, 49, 10), Decl(discriminatedUnionTypes3.ts, 50, 10))
+>type0 : Symbol(type0, Decl(discriminatedUnionTypes3.ts, 49, 17), Decl(discriminatedUnionTypes3.ts, 50, 17))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10), Decl(discriminatedUnionTypes3.ts, 5, 10))
+>type2 : Symbol(type2, Decl(discriminatedUnionTypes3.ts, 0, 10), Decl(discriminatedUnionTypes3.ts, 1, 10))
+
+        s.s // typeof s is S
+>s.s : Symbol(s, Decl(discriminatedUnionTypes3.ts, 49, 29))
+>s : Symbol(s, Decl(discriminatedUnionTypes3.ts, 52, 13))
+>s : Symbol(s, Decl(discriminatedUnionTypes3.ts, 49, 29))
+
+        s.sub.type0.x // type of s.sub.type is X
+>s.sub.type0.x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 4, 20))
+>s.sub.type0 : Symbol(type0, Decl(discriminatedUnionTypes3.ts, 49, 17))
+>s.sub : Symbol(sub, Decl(discriminatedUnionTypes3.ts, 49, 10))
+>s : Symbol(s, Decl(discriminatedUnionTypes3.ts, 52, 13))
+>sub : Symbol(sub, Decl(discriminatedUnionTypes3.ts, 49, 10))
+>type0 : Symbol(type0, Decl(discriminatedUnionTypes3.ts, 49, 17))
+>x : Symbol(x, Decl(discriminatedUnionTypes3.ts, 4, 20))
+
+        s.sub.type0.type1.a // type of s.sub.type.type is A
+>s.sub.type0.type1.a : Symbol(a, Decl(discriminatedUnionTypes3.ts, 0, 22))
+>s.sub.type0.type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10))
+>s.sub.type0 : Symbol(type0, Decl(discriminatedUnionTypes3.ts, 49, 17))
+>s.sub : Symbol(sub, Decl(discriminatedUnionTypes3.ts, 49, 10))
+>s : Symbol(s, Decl(discriminatedUnionTypes3.ts, 52, 13))
+>sub : Symbol(sub, Decl(discriminatedUnionTypes3.ts, 49, 10))
+>type0 : Symbol(type0, Decl(discriminatedUnionTypes3.ts, 49, 17))
+>type1 : Symbol(type1, Decl(discriminatedUnionTypes3.ts, 4, 10))
+>a : Symbol(a, Decl(discriminatedUnionTypes3.ts, 0, 22))
+
+    } else {
+        s.s // type error!
+>s : Symbol(s, Decl(discriminatedUnionTypes3.ts, 52, 13))
+    }
+}
+
 // Repro from #44435
 
 type Correct = {
->Correct : Symbol(Correct, Decl(discriminatedUnionTypes3.ts, 0, 0))
+>Correct : Symbol(Correct, Decl(discriminatedUnionTypes3.ts, 60, 1))
 
 	code: string
->code : Symbol(code, Decl(discriminatedUnionTypes3.ts, 2, 16))
+>code : Symbol(code, Decl(discriminatedUnionTypes3.ts, 64, 16))
 
 	property: true
->property : Symbol(property, Decl(discriminatedUnionTypes3.ts, 3, 13))
+>property : Symbol(property, Decl(discriminatedUnionTypes3.ts, 65, 13))
 
 	err: undefined
->err : Symbol(err, Decl(discriminatedUnionTypes3.ts, 4, 15))
+>err : Symbol(err, Decl(discriminatedUnionTypes3.ts, 66, 15))
 }
 type Err = {
->Err : Symbol(Err, Decl(discriminatedUnionTypes3.ts, 6, 1))
+>Err : Symbol(Err, Decl(discriminatedUnionTypes3.ts, 68, 1))
 
 	err: `${string} is wrong!`
->err : Symbol(err, Decl(discriminatedUnionTypes3.ts, 7, 12))
+>err : Symbol(err, Decl(discriminatedUnionTypes3.ts, 69, 12))
 }
 type SomeReturnType = Correct | Err;
->SomeReturnType : Symbol(SomeReturnType, Decl(discriminatedUnionTypes3.ts, 9, 1))
->Correct : Symbol(Correct, Decl(discriminatedUnionTypes3.ts, 0, 0))
->Err : Symbol(Err, Decl(discriminatedUnionTypes3.ts, 6, 1))
+>SomeReturnType : Symbol(SomeReturnType, Decl(discriminatedUnionTypes3.ts, 71, 1))
+>Correct : Symbol(Correct, Decl(discriminatedUnionTypes3.ts, 60, 1))
+>Err : Symbol(Err, Decl(discriminatedUnionTypes3.ts, 68, 1))
 
 const example: SomeReturnType = {} as SomeReturnType;
->example : Symbol(example, Decl(discriminatedUnionTypes3.ts, 12, 5))
->SomeReturnType : Symbol(SomeReturnType, Decl(discriminatedUnionTypes3.ts, 9, 1))
->SomeReturnType : Symbol(SomeReturnType, Decl(discriminatedUnionTypes3.ts, 9, 1))
+>example : Symbol(example, Decl(discriminatedUnionTypes3.ts, 74, 5))
+>SomeReturnType : Symbol(SomeReturnType, Decl(discriminatedUnionTypes3.ts, 71, 1))
+>SomeReturnType : Symbol(SomeReturnType, Decl(discriminatedUnionTypes3.ts, 71, 1))
 
 if (example.err === undefined) {
->example.err : Symbol(err, Decl(discriminatedUnionTypes3.ts, 4, 15), Decl(discriminatedUnionTypes3.ts, 7, 12))
->example : Symbol(example, Decl(discriminatedUnionTypes3.ts, 12, 5))
->err : Symbol(err, Decl(discriminatedUnionTypes3.ts, 4, 15), Decl(discriminatedUnionTypes3.ts, 7, 12))
+>example.err : Symbol(err, Decl(discriminatedUnionTypes3.ts, 66, 15), Decl(discriminatedUnionTypes3.ts, 69, 12))
+>example : Symbol(example, Decl(discriminatedUnionTypes3.ts, 74, 5))
+>err : Symbol(err, Decl(discriminatedUnionTypes3.ts, 66, 15), Decl(discriminatedUnionTypes3.ts, 69, 12))
 >undefined : Symbol(undefined)
 
 	example.property;  // true
->example.property : Symbol(property, Decl(discriminatedUnionTypes3.ts, 3, 13))
->example : Symbol(example, Decl(discriminatedUnionTypes3.ts, 12, 5))
->property : Symbol(property, Decl(discriminatedUnionTypes3.ts, 3, 13))
+>example : Symbol(example, Decl(discriminatedUnionTypes3.ts, 74, 5))
 }
+
diff --git a/tests/baselines/reference/discriminatedUnionTypes3.types b/tests/baselines/reference/discriminatedUnionTypes3.types
index 8c645a1773592..b3a62457bfd99 100644
--- a/tests/baselines/reference/discriminatedUnionTypes3.types
+++ b/tests/baselines/reference/discriminatedUnionTypes3.types
@@ -1,4 +1,226 @@
 === tests/cases/conformance/types/union/discriminatedUnionTypes3.ts ===
+type A = { type2: "a", a: number }
+>A : A
+>type2 : "a"
+>a : number
+
+type B = { type2: "b", b: number }
+>B : B
+>type2 : "b"
+>b : number
+
+type C = { type2: "c", b: number | string }
+>C : C
+>type2 : "c"
+>b : string | number
+
+type X = { type1: A, x: string }
+>X : X
+>type1 : A
+>x : string
+
+type Y = { type1: B, y: string }
+>Y : Y
+>type1 : B
+>y : string
+
+type Z = { type1: C, z: string }
+>Z : Z
+>type1 : C
+>z : string
+
+type W = { type1: undefined }
+>W : W
+>type1 : undefined
+
+function f32(x: X | Y) {
+>f32 : (x: X | Y) => void
+>x : X | Y
+
+    switch (x.type1.type2) {
+>x.type1.type2 : "a" | "b"
+>x.type1 : A | B
+>x : X | Y
+>type1 : A | B
+>type2 : "a" | "b"
+
+        case "a":
+>"a" : "a"
+
+            x.x // typeof x is X
+>x.x : string
+>x : X
+>x : string
+
+            break;
+        case "b":
+>"b" : "b"
+
+            x.y // typeof x is Y
+>x.y : string
+>x : Y
+>y : string
+
+            break;
+    }
+}
+
+function f33(x: A | B) {
+>f33 : (x: A | B) => void
+>x : A | B
+
+    switch (x.type2) {
+>x.type2 : "a" | "b"
+>x : A | B
+>type2 : "a" | "b"
+
+        case "a":
+>"a" : "a"
+
+            x // typeof x is X
+>x : A
+
+            break;
+        case "b":
+>"b" : "b"
+
+            x // typeof x is Y
+>x : B
+
+            break;
+    }
+}
+
+function f34(x: X | Y) {
+>f34 : (x: X | Y) => void
+>x : X | Y
+
+    if (x.type1.type2 === "a") {
+>x.type1.type2 === "a" : boolean
+>x.type1.type2 : "a" | "b"
+>x.type1 : A | B
+>x : X | Y
+>type1 : A | B
+>type2 : "a" | "b"
+>"a" : "a"
+
+        x.x // typeof x is X
+>x.x : string
+>x : X
+>x : string
+
+    } else if (x.type1.type2 === "b") {
+>x.type1.type2 === "b" : boolean
+>x.type1.type2 : "b"
+>x.type1 : B
+>x : Y
+>type1 : B
+>type2 : "b"
+>"b" : "b"
+
+        x.y // typeof x is Y
+>x.y : string
+>x : Y
+>y : string
+    }
+}
+
+function f35(x: X | W) {
+>f35 : (x: X | W) => void
+>x : X | W
+
+    if (x.type1?.type2 === "a") {
+>x.type1?.type2 === "a" : boolean
+>x.type1?.type2 : "a" | undefined
+>x.type1 : A | undefined
+>x : X | W
+>type1 : A | undefined
+>type2 : "a" | undefined
+>"a" : "a"
+
+        x.x
+>x.x : string
+>x : X
+>x : string
+    }
+}
+
+function f36(x: X | W) {
+>f36 : (x: X | W) => void
+>x : X | W
+
+    x.type1?.type2 ?? x;
+>x.type1?.type2 ?? x : "a" | W
+>x.type1?.type2 : "a" | undefined
+>x.type1 : A | undefined
+>x : X | W
+>type1 : A | undefined
+>type2 : "a" | undefined
+>x : W
+}
+
+type S = { sub: { type0: X }, s: string }
+>S : S
+>sub : { type0: X; }
+>type0 : X
+>s : string
+
+type T = { sub: { type0: Y }, t: string }
+>T : T
+>sub : { type0: Y; }
+>type0 : Y
+>t : string
+
+function f37(s: S | T) {
+>f37 : (s: S | T) => void
+>s : S | T
+
+    if (s.sub.type0.type1.type2 === "a") {
+>s.sub.type0.type1.type2 === "a" : boolean
+>s.sub.type0.type1.type2 : "a" | "b"
+>s.sub.type0.type1 : A | B
+>s.sub.type0 : X | Y
+>s.sub : { type0: X; } | { type0: Y; }
+>s : S | T
+>sub : { type0: X; } | { type0: Y; }
+>type0 : X | Y
+>type1 : A | B
+>type2 : "a" | "b"
+>"a" : "a"
+
+        s.s // typeof s is S
+>s.s : string
+>s : S
+>s : string
+
+        s.sub.type0.x // type of s.sub.type is X
+>s.sub.type0.x : string
+>s.sub.type0 : X
+>s.sub : { type0: X; }
+>s : S
+>sub : { type0: X; }
+>type0 : X
+>x : string
+
+        s.sub.type0.type1.a // type of s.sub.type.type is A
+>s.sub.type0.type1.a : number
+>s.sub.type0.type1 : A
+>s.sub.type0 : X
+>s.sub : { type0: X; }
+>s : S
+>sub : { type0: X; }
+>type0 : X
+>type1 : A
+>a : number
+
+    } else {
+        s.s // type error!
+>s.s : any
+>s : T
+>s : any
+    }
+}
+
 // Repro from #44435
 
 type Correct = {
@@ -36,7 +258,8 @@ if (example.err === undefined) {
 >undefined : undefined
 
 	example.property;  // true
->example.property : true
->example : Correct
->property : true
+>example.property : any
+>example : SomeReturnType
+>property : any
 }
+
diff --git a/tests/baselines/reference/nonNullReferenceMatching.js b/tests/baselines/reference/nonNullReferenceMatching.js
index abb0d5a96db30..713fc4e56e51b 100644
--- a/tests/baselines/reference/nonNullReferenceMatching.js
+++ b/tests/baselines/reference/nonNullReferenceMatching.js
@@ -10,6 +10,14 @@ type ComponentProps = {
     thumbXProps: ThumbProps;
 }
 
+type ThumbProps2 = {
+    elementRef: ElementRef | null;
+}
+
+type ComponentProps2 = {
+    thumbYProps: ThumbProps2 | null;
+}
+
 class Component {
     props!: ComponentProps;
     public thumbYElementRef = (ref: HTMLElement | null) => {
@@ -31,6 +39,17 @@ class Component {
 
         typeof this.props!.thumbXProps!.elementRef === 'function' && ((this.props)!.thumbXProps)!.elementRef(ref);
     };
+}
+
+class Component2 {
+    props!: ComponentProps2;
+    public thumbYElementRef = (ref: HTMLElement | null) => {
+        typeof this.props.thumbYProps!.elementRef === 'function' && this.props.thumbYProps!.elementRef(ref);
+
+        typeof (this.props.thumbYProps!.elementRef) === 'function' && this.props.thumbYProps!.elementRef(ref);
+
+        typeof ((this.props).thumbYProps!.elementRef)! === 'function' && this.props.thumbYProps!.elementRef(ref);
+    }
 }
 
 //// [nonNullReferenceMatching.js]
@@ -52,3 +71,14 @@ var Component = /** @class */ (function () {
     }
     return Component;
 }());
+var Component2 = /** @class */ (function () {
+    function Component2() {
+        var _this = this;
+        this.thumbYElementRef = function (ref) {
+            typeof _this.props.thumbYProps.elementRef === 'function' && _this.props.thumbYProps.elementRef(ref);
+            typeof (_this.props.thumbYProps.elementRef) === 'function' && _this.props.thumbYProps.elementRef(ref);
+            typeof ((_this.props).thumbYProps.elementRef) === 'function' && _this.props.thumbYProps.elementRef(ref);
+        };
+    }
+    return Component2;
+}());
diff --git a/tests/baselines/reference/nonNullReferenceMatching.symbols b/tests/baselines/reference/nonNullReferenceMatching.symbols
index ee9c608cea498..fe43bab39632f 100644
--- a/tests/baselines/reference/nonNullReferenceMatching.symbols
+++ b/tests/baselines/reference/nonNullReferenceMatching.symbols
@@ -24,170 +24,251 @@ type ComponentProps = {
 >ThumbProps : Symbol(ThumbProps, Decl(nonNullReferenceMatching.ts, 0, 56))
 }
 
+type ThumbProps2 = {
+>ThumbProps2 : Symbol(ThumbProps2, Decl(nonNullReferenceMatching.ts, 9, 1))
+
+    elementRef: ElementRef | null;
+>elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>ElementRef : Symbol(ElementRef, Decl(nonNullReferenceMatching.ts, 0, 0))
+}
+
+type ComponentProps2 = {
+>ComponentProps2 : Symbol(ComponentProps2, Decl(nonNullReferenceMatching.ts, 13, 1))
+
+    thumbYProps: ThumbProps2 | null;
+>thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>ThumbProps2 : Symbol(ThumbProps2, Decl(nonNullReferenceMatching.ts, 9, 1))
+}
+
 class Component {
->Component : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
+>Component : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
 
     props!: ComponentProps;
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >ComponentProps : Symbol(ComponentProps, Decl(nonNullReferenceMatching.ts, 4, 1))
 
     public thumbYElementRef = (ref: HTMLElement | null) => {
->thumbYElementRef : Symbol(Component.thumbYElementRef, Decl(nonNullReferenceMatching.ts, 12, 27))
->ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 13, 31))
+>thumbYElementRef : Symbol(Component.thumbYElementRef, Decl(nonNullReferenceMatching.ts, 20, 27))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 21, 31))
 >HTMLElement : Symbol(HTMLElement, Decl(lib.dom.d.ts, --, --), Decl(lib.dom.d.ts, --, --))
 
         typeof this.props.thumbYProps!.elementRef === 'function' && this.props.thumbYProps!.elementRef(ref);
 >this.props.thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
->ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 13, 31))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 21, 31))
 
         typeof (this.props.thumbYProps!.elementRef) === 'function' && this.props.thumbYProps!.elementRef(ref);
 >this.props.thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
->ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 13, 31))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 21, 31))
 
         typeof ((this.props).thumbYProps!.elementRef)! === 'function' && this.props.thumbYProps!.elementRef(ref);
 >(this.props).thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >(this.props).thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 6, 23))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
->ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 13, 31))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 21, 31))
 
         typeof this.props.thumbXProps.elementRef === 'function' && this.props.thumbXProps.elementRef(ref);
 >this.props.thumbXProps.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbXProps.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
->ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 13, 31))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 21, 31))
 
         typeof this.props.thumbXProps.elementRef === 'function' && (this.props).thumbXProps.elementRef(ref);
 >this.props.thumbXProps.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >(this.props).thumbXProps.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >(this.props).thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
->ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 13, 31))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 21, 31))
 
         typeof this.props.thumbXProps.elementRef === 'function' && (this.props.thumbXProps).elementRef(ref);
 >this.props.thumbXProps.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >(this.props.thumbXProps).elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
->ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 13, 31))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 21, 31))
 
         typeof this.props.thumbXProps.elementRef === 'function' && ((this.props)!.thumbXProps)!.elementRef(ref);
 >this.props.thumbXProps.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >((this.props)!.thumbXProps)!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >(this.props)!.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
->ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 13, 31))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 21, 31))
 
         typeof (this.props.thumbXProps).elementRef === 'function' && ((this.props)!.thumbXProps)!.elementRef(ref);
 >(this.props.thumbXProps).elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >((this.props)!.thumbXProps)!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >(this.props)!.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
->ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 13, 31))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 21, 31))
 
         typeof this.props!.thumbXProps!.elementRef === 'function' && ((this.props)!.thumbXProps)!.elementRef(ref);
 >this.props!.thumbXProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >this.props!.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >((this.props)!.thumbXProps)!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
 >(this.props)!.thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
->this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
->this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 9, 1))
->props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 11, 17))
+>this.props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
+>this : Symbol(Component, Decl(nonNullReferenceMatching.ts, 17, 1))
+>props : Symbol(Component.props, Decl(nonNullReferenceMatching.ts, 19, 17))
 >thumbXProps : Symbol(thumbXProps, Decl(nonNullReferenceMatching.ts, 7, 29))
 >elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 2, 19))
->ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 13, 31))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 21, 31))
 
     };
 }
+
+class Component2 {
+>Component2 : Symbol(Component2, Decl(nonNullReferenceMatching.ts, 40, 1))
+
+    props!: ComponentProps2;
+>props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>ComponentProps2 : Symbol(ComponentProps2, Decl(nonNullReferenceMatching.ts, 13, 1))
+
+    public thumbYElementRef = (ref: HTMLElement | null) => {
+>thumbYElementRef : Symbol(Component2.thumbYElementRef, Decl(nonNullReferenceMatching.ts, 43, 28))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 44, 31))
+>HTMLElement : Symbol(HTMLElement, Decl(lib.dom.d.ts, --, --), Decl(lib.dom.d.ts, --, --))
+
+        typeof this.props.thumbYProps!.elementRef === 'function' && this.props.thumbYProps!.elementRef(ref);
+>this.props.thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>this.props.thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>this.props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>this : Symbol(Component2, Decl(nonNullReferenceMatching.ts, 40, 1))
+>props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>this.props.thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>this.props.thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>this.props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>this : Symbol(Component2, Decl(nonNullReferenceMatching.ts, 40, 1))
+>props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 44, 31))
+
+        typeof (this.props.thumbYProps!.elementRef) === 'function' && this.props.thumbYProps!.elementRef(ref);
+>this.props.thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>this.props.thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>this.props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>this : Symbol(Component2, Decl(nonNullReferenceMatching.ts, 40, 1))
+>props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>this.props.thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>this.props.thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>this.props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>this : Symbol(Component2, Decl(nonNullReferenceMatching.ts, 40, 1))
+>props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 44, 31))
+
+        typeof ((this.props).thumbYProps!.elementRef)! === 'function' && this.props.thumbYProps!.elementRef(ref);
+>(this.props).thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>(this.props).thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>this.props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>this : Symbol(Component2, Decl(nonNullReferenceMatching.ts, 40, 1))
+>props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>this.props.thumbYProps!.elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>this.props.thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>this.props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>this : Symbol(Component2, Decl(nonNullReferenceMatching.ts, 40, 1))
+>props : Symbol(Component2.props, Decl(nonNullReferenceMatching.ts, 42, 18))
+>thumbYProps : Symbol(thumbYProps, Decl(nonNullReferenceMatching.ts, 15, 24))
+>elementRef : Symbol(elementRef, Decl(nonNullReferenceMatching.ts, 11, 20))
+>ref : Symbol(ref, Decl(nonNullReferenceMatching.ts, 44, 31))
+    }
+}
diff --git a/tests/baselines/reference/nonNullReferenceMatching.types b/tests/baselines/reference/nonNullReferenceMatching.types
index 03ef70177c07f..8a4335bc0fc63 100644
--- a/tests/baselines/reference/nonNullReferenceMatching.types
+++ b/tests/baselines/reference/nonNullReferenceMatching.types
@@ -21,6 +21,22 @@ type ComponentProps = {
 >thumbXProps : ThumbProps
 }
 
+type ThumbProps2 = {
+>ThumbProps2 : ThumbProps2
+
+    elementRef: ElementRef | null;
+>elementRef : ElementRef | null
+>null : null
+}
+
+type ComponentProps2 = {
+>ComponentProps2 : ComponentProps2
+
+    thumbYProps: ThumbProps2 | null;
+>thumbYProps : ThumbProps2 | null
+>null : null
+}
+
 class Component {
 >Component : Component
 
@@ -49,11 +65,11 @@ class Component {
 >this.props.thumbYProps!.elementRef(ref) : void
 >this.props.thumbYProps!.elementRef : ElementRef
 >this.props.thumbYProps! : ThumbProps
->this.props.thumbYProps : ThumbProps | undefined
+>this.props.thumbYProps : ThumbProps
 >this.props : ComponentProps
 >this : this
 >props : ComponentProps
->thumbYProps : ThumbProps | undefined
+>thumbYProps : ThumbProps
 >elementRef : ElementRef
 >ref : HTMLElement | null
 
@@ -64,21 +80,21 @@ class Component {
 >(this.props.thumbYProps!.elementRef) : ElementRef | undefined
 >this.props.thumbYProps!.elementRef : ElementRef | undefined
 >this.props.thumbYProps! : ThumbProps
->this.props.thumbYProps : ThumbProps | undefined
+>this.props.thumbYProps : ThumbProps
 >this.props : ComponentProps
 >this : this
 >props : ComponentProps
->thumbYProps : ThumbProps | undefined
+>thumbYProps : ThumbProps
 >elementRef : ElementRef | undefined
 >'function' : "function"
 >this.props.thumbYProps!.elementRef(ref) : void
 >this.props.thumbYProps!.elementRef : ElementRef
 >this.props.thumbYProps! : ThumbProps
->this.props.thumbYProps : ThumbProps | undefined
+>this.props.thumbYProps : ThumbProps
 >this.props : ComponentProps
 >this : this
 >props : ComponentProps
->thumbYProps : ThumbProps | undefined
+>thumbYProps : ThumbProps
 >elementRef : ElementRef
 >ref : HTMLElement | null
 
@@ -90,22 +106,22 @@ class Component {
 >((this.props).thumbYProps!.elementRef) : ElementRef | undefined
 >(this.props).thumbYProps!.elementRef : ElementRef | undefined
 >(this.props).thumbYProps! : ThumbProps
->(this.props).thumbYProps : ThumbProps | undefined
+>(this.props).thumbYProps : ThumbProps
 >(this.props) : ComponentProps
 >this.props : ComponentProps
 >this : this
 >props : ComponentProps
->thumbYProps : ThumbProps | undefined
+>thumbYProps : ThumbProps
 >elementRef : ElementRef | undefined
 >'function' : "function"
 >this.props.thumbYProps!.elementRef(ref) : void
 >this.props.thumbYProps!.elementRef : ElementRef
 >this.props.thumbYProps! : ThumbProps
->this.props.thumbYProps : ThumbProps | undefined
+>this.props.thumbYProps : ThumbProps
 >this.props : ComponentProps
 >this : this
 >props : ComponentProps
->thumbYProps : ThumbProps | undefined
+>thumbYProps : ThumbProps
 >elementRef : ElementRef
 >ref : HTMLElement | null
 
@@ -260,3 +276,93 @@ class Component {
 
     };
 }
+
+class Component2 {
+>Component2 : Component2
+
+    props!: ComponentProps2;
+>props : ComponentProps2
+
+    public thumbYElementRef = (ref: HTMLElement | null) => {
+>thumbYElementRef : (ref: HTMLElement | null) => void
+>(ref: HTMLElement | null) => {        typeof this.props.thumbYProps!.elementRef === 'function' && this.props.thumbYProps!.elementRef(ref);        typeof (this.props.thumbYProps!.elementRef) === 'function' && this.props.thumbYProps!.elementRef(ref);        typeof ((this.props).thumbYProps!.elementRef)! === 'function' && this.props.thumbYProps!.elementRef(ref);    } : (ref: HTMLElement | null) => void
+>ref : HTMLElement | null
+>null : null
+
+        typeof this.props.thumbYProps!.elementRef === 'function' && this.props.thumbYProps!.elementRef(ref);
+>typeof this.props.thumbYProps!.elementRef === 'function' && this.props.thumbYProps!.elementRef(ref) : false | void
+>typeof this.props.thumbYProps!.elementRef === 'function' : boolean
+>typeof this.props.thumbYProps!.elementRef : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>this.props.thumbYProps!.elementRef : ElementRef | null
+>this.props.thumbYProps! : ThumbProps2
+>this.props.thumbYProps : ThumbProps2 | null
+>this.props : ComponentProps2
+>this : this
+>props : ComponentProps2
+>thumbYProps : ThumbProps2 | null
+>elementRef : ElementRef | null
+>'function' : "function"
+>this.props.thumbYProps!.elementRef(ref) : void
+>this.props.thumbYProps!.elementRef : ElementRef
+>this.props.thumbYProps! : ThumbProps2
+>this.props.thumbYProps : ThumbProps2
+>this.props : ComponentProps2
+>this : this
+>props : ComponentProps2
+>thumbYProps : ThumbProps2
+>elementRef : ElementRef
+>ref : HTMLElement | null
+
+        typeof (this.props.thumbYProps!.elementRef) === 'function' && this.props.thumbYProps!.elementRef(ref);
+>typeof (this.props.thumbYProps!.elementRef) === 'function' && this.props.thumbYProps!.elementRef(ref) : false | void
+>typeof (this.props.thumbYProps!.elementRef) === 'function' : boolean
+>typeof (this.props.thumbYProps!.elementRef) : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>(this.props.thumbYProps!.elementRef) : ElementRef | null
+>this.props.thumbYProps!.elementRef : ElementRef | null
+>this.props.thumbYProps! : ThumbProps2
+>this.props.thumbYProps : ThumbProps2
+>this.props : ComponentProps2
+>this : this
+>props : ComponentProps2
+>thumbYProps : ThumbProps2
+>elementRef : ElementRef | null
+>'function' : "function"
+>this.props.thumbYProps!.elementRef(ref) : void
+>this.props.thumbYProps!.elementRef : ElementRef
+>this.props.thumbYProps! : ThumbProps2
+>this.props.thumbYProps : ThumbProps2
+>this.props : ComponentProps2
+>this : this
+>props : ComponentProps2
+>thumbYProps : ThumbProps2
+>elementRef : ElementRef
+>ref : HTMLElement | null
+
+        typeof ((this.props).thumbYProps!.elementRef)! === 'function' && this.props.thumbYProps!.elementRef(ref);
+>typeof ((this.props).thumbYProps!.elementRef)! === 'function' && this.props.thumbYProps!.elementRef(ref) : false | void
+>typeof ((this.props).thumbYProps!.elementRef)! === 'function' : boolean
+>typeof ((this.props).thumbYProps!.elementRef)! : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>((this.props).thumbYProps!.elementRef)! : ElementRef
+>((this.props).thumbYProps!.elementRef) : ElementRef | null
+>(this.props).thumbYProps!.elementRef : ElementRef | null
+>(this.props).thumbYProps! : ThumbProps2
+>(this.props).thumbYProps : ThumbProps2
+>(this.props) : ComponentProps2
+>this.props : ComponentProps2
+>this : this
+>props : ComponentProps2
+>thumbYProps : ThumbProps2
+>elementRef : ElementRef | null
+>'function' : "function"
+>this.props.thumbYProps!.elementRef(ref) : void
+>this.props.thumbYProps!.elementRef : ElementRef
+>this.props.thumbYProps! : ThumbProps2
+>this.props.thumbYProps : ThumbProps2
+>this.props : ComponentProps2
+>this : this
+>props : ComponentProps2
+>thumbYProps : ThumbProps2
+>elementRef : ElementRef
+>ref : HTMLElement | null
+    }
+}
diff --git a/tests/baselines/reference/templateLiteralTypes3.errors.txt b/tests/baselines/reference/templateLiteralTypes3.errors.txt
index d9e2608ac88b6..eb1b4a8c3bc0f 100644
--- a/tests/baselines/reference/templateLiteralTypes3.errors.txt
+++ b/tests/baselines/reference/templateLiteralTypes3.errors.txt
@@ -7,9 +7,11 @@ tests/cases/conformance/types/literal/templateLiteralTypes3.ts(74,5): error TS23
   Type '"*false*"' is not assignable to type '`*${number}*`'.
 tests/cases/conformance/types/literal/templateLiteralTypes3.ts(133,9): error TS2367: This condition will always return 'false' since the types '`foo-${string}`' and '`baz-${string}`' have no overlap.
 tests/cases/conformance/types/literal/templateLiteralTypes3.ts(141,9): error TS2367: This condition will always return 'false' since the types '`foo-${T}`' and '`baz-${T}`' have no overlap.
+tests/cases/conformance/types/literal/templateLiteralTypes3.ts(169,16): error TS2339: Property 'response' does not exist on type 'Action'.
+  Property 'response' does not exist on type '{ type: `${string}_REQUEST`; }'.
 
 
-==== tests/cases/conformance/types/literal/templateLiteralTypes3.ts (8 errors) ====
+==== tests/cases/conformance/types/literal/templateLiteralTypes3.ts (9 errors) ====
     // Inference from template literal type to template literal type
     
     type Foo1<T> = T extends `*${infer U}*` ? U : never;
@@ -196,6 +198,9 @@ tests/cases/conformance/types/literal/templateLiteralTypes3.ts(141,9): error TS2
         if (action.type === 'FOO_SUCCESS') {
             action.type;
             action.response;
+                   ~~~~~~~~
+!!! error TS2339: Property 'response' does not exist on type 'Action'.
+!!! error TS2339:   Property 'response' does not exist on type '{ type: `${string}_REQUEST`; }'.
         }
     }
     
diff --git a/tests/baselines/reference/templateLiteralTypes3.symbols b/tests/baselines/reference/templateLiteralTypes3.symbols
index 47f4ee7fe6e53..7443bee0540eb 100644
--- a/tests/baselines/reference/templateLiteralTypes3.symbols
+++ b/tests/baselines/reference/templateLiteralTypes3.symbols
@@ -505,14 +505,12 @@ function reducer(action: Action) {
 >type : Symbol(type, Decl(templateLiteralTypes3.ts, 162, 7), Decl(templateLiteralTypes3.ts, 163, 7))
 
         action.type;
->action.type : Symbol(type, Decl(templateLiteralTypes3.ts, 163, 7))
+>action.type : Symbol(type, Decl(templateLiteralTypes3.ts, 162, 7), Decl(templateLiteralTypes3.ts, 163, 7))
 >action : Symbol(action, Decl(templateLiteralTypes3.ts, 165, 17))
->type : Symbol(type, Decl(templateLiteralTypes3.ts, 163, 7))
+>type : Symbol(type, Decl(templateLiteralTypes3.ts, 162, 7), Decl(templateLiteralTypes3.ts, 163, 7))
 
         action.response;
->action.response : Symbol(response, Decl(templateLiteralTypes3.ts, 163, 34))
 >action : Symbol(action, Decl(templateLiteralTypes3.ts, 165, 17))
->response : Symbol(response, Decl(templateLiteralTypes3.ts, 163, 34))
     }
 }
 
diff --git a/tests/baselines/reference/templateLiteralTypes3.types b/tests/baselines/reference/templateLiteralTypes3.types
index 27d780c7e22ac..c1c6b91f83bdd 100644
--- a/tests/baselines/reference/templateLiteralTypes3.types
+++ b/tests/baselines/reference/templateLiteralTypes3.types
@@ -503,13 +503,13 @@ function reducer(action: Action) {
 
         action.type;
 >action.type : "FOO_SUCCESS"
->action : { type: `${string}_SUCCESS`; response: string; }
+>action : Action
 >type : "FOO_SUCCESS"
 
         action.response;
->action.response : string
->action : { type: `${string}_SUCCESS`; response: string; }
->response : string
+>action.response : any
+>action : Action
+>response : any
     }
 }
 
diff --git a/tests/baselines/reference/typeGuardAccordingToProperty.errors.txt b/tests/baselines/reference/typeGuardAccordingToProperty.errors.txt
new file mode 100644
index 0000000000000..acff40b61bc67
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToProperty.errors.txt
@@ -0,0 +1,281 @@
+tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty.ts(66,11): error TS2339: Property 'b1' does not exist on type 'Boolean1 | Boolean2'.
+  Property 'b1' does not exist on type 'Boolean2'.
+tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty.ts(67,11): error TS2339: Property 'b2' does not exist on type 'Boolean1 | Boolean2'.
+  Property 'b2' does not exist on type 'Boolean1'.
+tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty.ts(80,11): error TS2339: Property 'b1' does not exist on type 'Boolean1 | Boolean2'.
+  Property 'b1' does not exist on type 'Boolean2'.
+tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty.ts(81,11): error TS2339: Property 'b2' does not exist on type 'Boolean1 | Boolean2'.
+  Property 'b2' does not exist on type 'Boolean1'.
+
+
+==== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty.ts (4 errors) ====
+    // Primitive value ---- boolean bigint number string symbol undefined function object
+    // ts special type ---- any, void, unknown, union, intersection
+    
+    //// Property Access ---- a.b
+    //// Element Access ---- a["b"]
+    
+    interface Boolean1 {
+        key: boolean;
+        b1: number;
+    };
+    
+    interface Boolean2 {
+        key: boolean;
+        b2: number;
+    };
+    
+    interface BigInt1 {
+        key: bigint;
+        bi1: number;
+    };
+    
+    interface Number1 {
+        key: number;
+        n1: number;
+    };
+    
+    interface String1 {
+        key: string;
+        st1: number;
+    }
+    
+    interface Symbol1 {
+        key: symbol;
+        sy1: number;
+    }
+    
+    interface Undefined1 {
+        key: undefined;
+        u1: number;
+    }
+    
+    interface Function1 {
+        key: () => void;
+        f1: number;
+    }
+    
+    interface Obejct1 {
+        key: {
+            notEmpty: number;
+        };
+        o1: number;
+    }
+    
+    type Union1 = Boolean1 | Boolean2 | Number1;
+    type Union2 = Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1;
+    
+    function f1_1(u: Union1) {
+        if (typeof u.key !== 'boolean') {
+            u;      // Number1
+            u.n1;   // number
+        }
+    }
+    function f1_2(u: Union1) {
+        if (typeof u.key === 'boolean') {
+            u;      // Bolean1 | Bolean2
+            u.b1;   // Error
+              ~~
+!!! error TS2339: Property 'b1' does not exist on type 'Boolean1 | Boolean2'.
+!!! error TS2339:   Property 'b1' does not exist on type 'Boolean2'.
+            u.b2;   // Error
+              ~~
+!!! error TS2339: Property 'b2' does not exist on type 'Boolean1 | Boolean2'.
+!!! error TS2339:   Property 'b2' does not exist on type 'Boolean1'.
+        }
+    }
+    
+    function f1ElementAccess_1(u: Union1) {
+        if (typeof u["key"] !== 'boolean') {
+            u;      // Number1
+            u.n1;   // number
+        }
+    }
+    function f1ElementAccess_2(u: Union1) {
+        if (typeof u["key"] === 'boolean') {
+            u;      // Bolean1 | Bolean2
+            u.b1;   // Error
+              ~~
+!!! error TS2339: Property 'b1' does not exist on type 'Boolean1 | Boolean2'.
+!!! error TS2339:   Property 'b1' does not exist on type 'Boolean2'.
+            u.b2;   // Error
+              ~~
+!!! error TS2339: Property 'b2' does not exist on type 'Boolean1 | Boolean2'.
+!!! error TS2339:   Property 'b2' does not exist on type 'Boolean1'.
+        }
+    }
+    
+    function f1_Plus(u: Union1) {
+        if (typeof u.key !== 'boolean') {
+            throw new Error();
+        }
+        u;  // Bolean1 | Bolean2
+        if (typeof u.key === 'boolean') {
+            throw new Error();
+        }
+        u;  // never
+    }
+    
+    // boolean bigint number string symbol undefined function object
+    function f2_1(u: Union2) {
+        if (typeof u.key === 'bigint') {
+            u;      // BigInt1
+            u.bi1;
+        }
+        if (typeof u.key == 'bigint') {
+            u;      // BigInt1
+            u.bi1;
+        }
+    }
+    function f2_2(u: Union2) {
+        if (typeof u.key === 'boolean') {
+            u;      // Boolean1
+            u.b1;
+        }
+        if (typeof u.key == 'boolean') {
+            u;      // Boolean1
+            u.b1;
+        }
+    }
+    function f2_3(u: Union2) {
+        if (typeof u.key === 'number') {
+            u;      // Number1
+            u.n1;
+        }
+        if (typeof u.key == 'number') {
+            u;      // Number1
+            u.n1;
+        }
+    }
+    function f2_4(u: Union2) {
+        if (typeof u.key === 'string') {
+            u;      // String1
+            u.st1;
+        }
+        if (typeof u.key == 'string') {
+            u;      // String1
+            u.st1;
+        }
+    }
+    function f2_5(u: Union2) {
+        if (typeof u.key === 'symbol') {
+            u;      // Symbol1
+            u.sy1;
+        }
+        if (typeof u.key == 'symbol') {
+            u;      // Symbol1
+            u.sy1;
+        }
+    }
+    function f2_6(u: Union2) {
+        if (typeof u.key === 'undefined') {
+            u;      // Undefined1
+            u.u1
+        }
+        if (typeof u.key == 'undefined') {
+            u;      // Undefined1
+            u.u1
+        }
+    }
+    function f2_7(u: Union2) {
+        if (typeof u.key === 'function') {
+            u;      // Function1
+            u.f1;
+        }
+        if (typeof u.key == 'function') {
+            u;      // Function1
+            u.f1;
+        }
+    }
+    function f2_8(u: Union2) {
+        if (typeof u.key === 'object') {
+            u;      // Object1
+            u.o1;
+        }
+        if (typeof u.key == 'object') {
+            u;      // Object1
+            u.o1;
+        }
+    }
+    
+    function f2Not_1(u: Union2) {
+        if (typeof u.key !== 'bigint') {
+            u;      // not BigInt1
+        }
+        if (typeof u.key != 'bigint') {
+            u;      // not BigInt1
+        }
+    }
+    function f2Not_2(u: Union2) {
+        if (typeof u.key !== 'boolean') {
+            u;      // not Boolean1
+        }
+        if (typeof u.key != 'boolean') {
+            u;      // not Boolean1
+        }
+    }
+    
+    function f2Not_3(u: Union2) {
+        if (typeof u.key !== 'number') {
+            u;      // not Number1
+        }
+        if (typeof u.key != 'number') {
+            u;      // not Number1
+        }
+    }
+    
+    function f2Not_4(u: Union2) {
+        if (typeof u.key !== 'string') {
+            u;      // not String1
+        }
+        if (typeof u.key != 'string') {
+            u;      // not String1
+        }
+    }
+    
+    function f2Not_5(u: Union2) {
+        if (typeof u.key !== 'symbol') {
+            u;      // not Symbol1
+        }
+        if (typeof u.key != 'symbol') {
+            u;      // not Symbol1
+        }
+    }
+    
+    function f2Not_6(u: Union2) {
+        if (typeof u.key !== 'undefined') {
+            u;      // not Undefined1
+        }
+        if (typeof u.key != 'undefined') {
+            u;      // not Undefined1
+        }
+    }
+    
+    function f2Not_7(u: Union2) {
+        if (typeof u.key !== 'function') {
+            u;      // not Function1
+        }
+        if (typeof u.key != 'function') {
+            u;      // not Function1
+        }
+    }
+    
+    function f2Not_8(u: Union2) {
+        if (typeof u.key !== 'object') {
+            u;      // not Object1
+        }
+        if (typeof u.key != 'object') {
+            u;      // not Object1
+        }
+    }
+    
+    interface A { x: string, y: string };
+    interface B { x: number, y: number };
+    type X = A | B;
+    
+    function f3(bar: X) {
+        if (typeof bar.x === 'string') {
+            let y = bar.y; // string
+        }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/typeGuardAccordingToProperty.js b/tests/baselines/reference/typeGuardAccordingToProperty.js
new file mode 100644
index 0000000000000..3801c4de67008
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToProperty.js
@@ -0,0 +1,456 @@
+//// [typeGuardAccordingToProperty.ts]
+// Primitive value ---- boolean bigint number string symbol undefined function object
+// ts special type ---- any, void, unknown, union, intersection
+
+//// Property Access ---- a.b
+//// Element Access ---- a["b"]
+
+interface Boolean1 {
+    key: boolean;
+    b1: number;
+};
+
+interface Boolean2 {
+    key: boolean;
+    b2: number;
+};
+
+interface BigInt1 {
+    key: bigint;
+    bi1: number;
+};
+
+interface Number1 {
+    key: number;
+    n1: number;
+};
+
+interface String1 {
+    key: string;
+    st1: number;
+}
+
+interface Symbol1 {
+    key: symbol;
+    sy1: number;
+}
+
+interface Undefined1 {
+    key: undefined;
+    u1: number;
+}
+
+interface Function1 {
+    key: () => void;
+    f1: number;
+}
+
+interface Obejct1 {
+    key: {
+        notEmpty: number;
+    };
+    o1: number;
+}
+
+type Union1 = Boolean1 | Boolean2 | Number1;
+type Union2 = Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1;
+
+function f1_1(u: Union1) {
+    if (typeof u.key !== 'boolean') {
+        u;      // Number1
+        u.n1;   // number
+    }
+}
+function f1_2(u: Union1) {
+    if (typeof u.key === 'boolean') {
+        u;      // Bolean1 | Bolean2
+        u.b1;   // Error
+        u.b2;   // Error
+    }
+}
+
+function f1ElementAccess_1(u: Union1) {
+    if (typeof u["key"] !== 'boolean') {
+        u;      // Number1
+        u.n1;   // number
+    }
+}
+function f1ElementAccess_2(u: Union1) {
+    if (typeof u["key"] === 'boolean') {
+        u;      // Bolean1 | Bolean2
+        u.b1;   // Error
+        u.b2;   // Error
+    }
+}
+
+function f1_Plus(u: Union1) {
+    if (typeof u.key !== 'boolean') {
+        throw new Error();
+    }
+    u;  // Bolean1 | Bolean2
+    if (typeof u.key === 'boolean') {
+        throw new Error();
+    }
+    u;  // never
+}
+
+// boolean bigint number string symbol undefined function object
+function f2_1(u: Union2) {
+    if (typeof u.key === 'bigint') {
+        u;      // BigInt1
+        u.bi1;
+    }
+    if (typeof u.key == 'bigint') {
+        u;      // BigInt1
+        u.bi1;
+    }
+}
+function f2_2(u: Union2) {
+    if (typeof u.key === 'boolean') {
+        u;      // Boolean1
+        u.b1;
+    }
+    if (typeof u.key == 'boolean') {
+        u;      // Boolean1
+        u.b1;
+    }
+}
+function f2_3(u: Union2) {
+    if (typeof u.key === 'number') {
+        u;      // Number1
+        u.n1;
+    }
+    if (typeof u.key == 'number') {
+        u;      // Number1
+        u.n1;
+    }
+}
+function f2_4(u: Union2) {
+    if (typeof u.key === 'string') {
+        u;      // String1
+        u.st1;
+    }
+    if (typeof u.key == 'string') {
+        u;      // String1
+        u.st1;
+    }
+}
+function f2_5(u: Union2) {
+    if (typeof u.key === 'symbol') {
+        u;      // Symbol1
+        u.sy1;
+    }
+    if (typeof u.key == 'symbol') {
+        u;      // Symbol1
+        u.sy1;
+    }
+}
+function f2_6(u: Union2) {
+    if (typeof u.key === 'undefined') {
+        u;      // Undefined1
+        u.u1
+    }
+    if (typeof u.key == 'undefined') {
+        u;      // Undefined1
+        u.u1
+    }
+}
+function f2_7(u: Union2) {
+    if (typeof u.key === 'function') {
+        u;      // Function1
+        u.f1;
+    }
+    if (typeof u.key == 'function') {
+        u;      // Function1
+        u.f1;
+    }
+}
+function f2_8(u: Union2) {
+    if (typeof u.key === 'object') {
+        u;      // Object1
+        u.o1;
+    }
+    if (typeof u.key == 'object') {
+        u;      // Object1
+        u.o1;
+    }
+}
+
+function f2Not_1(u: Union2) {
+    if (typeof u.key !== 'bigint') {
+        u;      // not BigInt1
+    }
+    if (typeof u.key != 'bigint') {
+        u;      // not BigInt1
+    }
+}
+function f2Not_2(u: Union2) {
+    if (typeof u.key !== 'boolean') {
+        u;      // not Boolean1
+    }
+    if (typeof u.key != 'boolean') {
+        u;      // not Boolean1
+    }
+}
+
+function f2Not_3(u: Union2) {
+    if (typeof u.key !== 'number') {
+        u;      // not Number1
+    }
+    if (typeof u.key != 'number') {
+        u;      // not Number1
+    }
+}
+
+function f2Not_4(u: Union2) {
+    if (typeof u.key !== 'string') {
+        u;      // not String1
+    }
+    if (typeof u.key != 'string') {
+        u;      // not String1
+    }
+}
+
+function f2Not_5(u: Union2) {
+    if (typeof u.key !== 'symbol') {
+        u;      // not Symbol1
+    }
+    if (typeof u.key != 'symbol') {
+        u;      // not Symbol1
+    }
+}
+
+function f2Not_6(u: Union2) {
+    if (typeof u.key !== 'undefined') {
+        u;      // not Undefined1
+    }
+    if (typeof u.key != 'undefined') {
+        u;      // not Undefined1
+    }
+}
+
+function f2Not_7(u: Union2) {
+    if (typeof u.key !== 'function') {
+        u;      // not Function1
+    }
+    if (typeof u.key != 'function') {
+        u;      // not Function1
+    }
+}
+
+function f2Not_8(u: Union2) {
+    if (typeof u.key !== 'object') {
+        u;      // not Object1
+    }
+    if (typeof u.key != 'object') {
+        u;      // not Object1
+    }
+}
+
+interface A { x: string, y: string };
+interface B { x: number, y: number };
+type X = A | B;
+
+function f3(bar: X) {
+    if (typeof bar.x === 'string') {
+        let y = bar.y; // string
+    }
+}
+
+
+//// [typeGuardAccordingToProperty.js]
+"use strict";
+// Primitive value ---- boolean bigint number string symbol undefined function object
+// ts special type ---- any, void, unknown, union, intersection
+;
+;
+;
+;
+function f1_1(u) {
+    if (typeof u.key !== 'boolean') {
+        u; // Number1
+        u.n1; // number
+    }
+}
+function f1_2(u) {
+    if (typeof u.key === 'boolean') {
+        u; // Bolean1 | Bolean2
+        u.b1; // Error
+        u.b2; // Error
+    }
+}
+function f1ElementAccess_1(u) {
+    if (typeof u["key"] !== 'boolean') {
+        u; // Number1
+        u.n1; // number
+    }
+}
+function f1ElementAccess_2(u) {
+    if (typeof u["key"] === 'boolean') {
+        u; // Bolean1 | Bolean2
+        u.b1; // Error
+        u.b2; // Error
+    }
+}
+function f1_Plus(u) {
+    if (typeof u.key !== 'boolean') {
+        throw new Error();
+    }
+    u; // Bolean1 | Bolean2
+    if (typeof u.key === 'boolean') {
+        throw new Error();
+    }
+    u; // never
+}
+// boolean bigint number string symbol undefined function object
+function f2_1(u) {
+    if (typeof u.key === 'bigint') {
+        u; // BigInt1
+        u.bi1;
+    }
+    if (typeof u.key == 'bigint') {
+        u; // BigInt1
+        u.bi1;
+    }
+}
+function f2_2(u) {
+    if (typeof u.key === 'boolean') {
+        u; // Boolean1
+        u.b1;
+    }
+    if (typeof u.key == 'boolean') {
+        u; // Boolean1
+        u.b1;
+    }
+}
+function f2_3(u) {
+    if (typeof u.key === 'number') {
+        u; // Number1
+        u.n1;
+    }
+    if (typeof u.key == 'number') {
+        u; // Number1
+        u.n1;
+    }
+}
+function f2_4(u) {
+    if (typeof u.key === 'string') {
+        u; // String1
+        u.st1;
+    }
+    if (typeof u.key == 'string') {
+        u; // String1
+        u.st1;
+    }
+}
+function f2_5(u) {
+    if (typeof u.key === 'symbol') {
+        u; // Symbol1
+        u.sy1;
+    }
+    if (typeof u.key == 'symbol') {
+        u; // Symbol1
+        u.sy1;
+    }
+}
+function f2_6(u) {
+    if (typeof u.key === 'undefined') {
+        u; // Undefined1
+        u.u1;
+    }
+    if (typeof u.key == 'undefined') {
+        u; // Undefined1
+        u.u1;
+    }
+}
+function f2_7(u) {
+    if (typeof u.key === 'function') {
+        u; // Function1
+        u.f1;
+    }
+    if (typeof u.key == 'function') {
+        u; // Function1
+        u.f1;
+    }
+}
+function f2_8(u) {
+    if (typeof u.key === 'object') {
+        u; // Object1
+        u.o1;
+    }
+    if (typeof u.key == 'object') {
+        u; // Object1
+        u.o1;
+    }
+}
+function f2Not_1(u) {
+    if (typeof u.key !== 'bigint') {
+        u; // not BigInt1
+    }
+    if (typeof u.key != 'bigint') {
+        u; // not BigInt1
+    }
+}
+function f2Not_2(u) {
+    if (typeof u.key !== 'boolean') {
+        u; // not Boolean1
+    }
+    if (typeof u.key != 'boolean') {
+        u; // not Boolean1
+    }
+}
+function f2Not_3(u) {
+    if (typeof u.key !== 'number') {
+        u; // not Number1
+    }
+    if (typeof u.key != 'number') {
+        u; // not Number1
+    }
+}
+function f2Not_4(u) {
+    if (typeof u.key !== 'string') {
+        u; // not String1
+    }
+    if (typeof u.key != 'string') {
+        u; // not String1
+    }
+}
+function f2Not_5(u) {
+    if (typeof u.key !== 'symbol') {
+        u; // not Symbol1
+    }
+    if (typeof u.key != 'symbol') {
+        u; // not Symbol1
+    }
+}
+function f2Not_6(u) {
+    if (typeof u.key !== 'undefined') {
+        u; // not Undefined1
+    }
+    if (typeof u.key != 'undefined') {
+        u; // not Undefined1
+    }
+}
+function f2Not_7(u) {
+    if (typeof u.key !== 'function') {
+        u; // not Function1
+    }
+    if (typeof u.key != 'function') {
+        u; // not Function1
+    }
+}
+function f2Not_8(u) {
+    if (typeof u.key !== 'object') {
+        u; // not Object1
+    }
+    if (typeof u.key != 'object') {
+        u; // not Object1
+    }
+}
+;
+;
+function f3(bar) {
+    if (typeof bar.x === 'string') {
+        var y = bar.y; // string
+    }
+}
diff --git a/tests/baselines/reference/typeGuardAccordingToProperty.symbols b/tests/baselines/reference/typeGuardAccordingToProperty.symbols
new file mode 100644
index 0000000000000..36263507e4635
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToProperty.symbols
@@ -0,0 +1,702 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty.ts ===
+// Primitive value ---- boolean bigint number string symbol undefined function object
+// ts special type ---- any, void, unknown, union, intersection
+
+//// Property Access ---- a.b
+//// Element Access ---- a["b"]
+
+interface Boolean1 {
+>Boolean1 : Symbol(Boolean1, Decl(typeGuardAccordingToProperty.ts, 0, 0))
+
+    key: boolean;
+>key : Symbol(Boolean1.key, Decl(typeGuardAccordingToProperty.ts, 6, 20))
+
+    b1: number;
+>b1 : Symbol(Boolean1.b1, Decl(typeGuardAccordingToProperty.ts, 7, 17))
+
+};
+
+interface Boolean2 {
+>Boolean2 : Symbol(Boolean2, Decl(typeGuardAccordingToProperty.ts, 9, 2))
+
+    key: boolean;
+>key : Symbol(Boolean2.key, Decl(typeGuardAccordingToProperty.ts, 11, 20))
+
+    b2: number;
+>b2 : Symbol(Boolean2.b2, Decl(typeGuardAccordingToProperty.ts, 12, 17))
+
+};
+
+interface BigInt1 {
+>BigInt1 : Symbol(BigInt1, Decl(typeGuardAccordingToProperty.ts, 14, 2))
+
+    key: bigint;
+>key : Symbol(BigInt1.key, Decl(typeGuardAccordingToProperty.ts, 16, 19))
+
+    bi1: number;
+>bi1 : Symbol(BigInt1.bi1, Decl(typeGuardAccordingToProperty.ts, 17, 16))
+
+};
+
+interface Number1 {
+>Number1 : Symbol(Number1, Decl(typeGuardAccordingToProperty.ts, 19, 2))
+
+    key: number;
+>key : Symbol(Number1.key, Decl(typeGuardAccordingToProperty.ts, 21, 19))
+
+    n1: number;
+>n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToProperty.ts, 22, 16))
+
+};
+
+interface String1 {
+>String1 : Symbol(String1, Decl(typeGuardAccordingToProperty.ts, 24, 2))
+
+    key: string;
+>key : Symbol(String1.key, Decl(typeGuardAccordingToProperty.ts, 26, 19))
+
+    st1: number;
+>st1 : Symbol(String1.st1, Decl(typeGuardAccordingToProperty.ts, 27, 16))
+}
+
+interface Symbol1 {
+>Symbol1 : Symbol(Symbol1, Decl(typeGuardAccordingToProperty.ts, 29, 1))
+
+    key: symbol;
+>key : Symbol(Symbol1.key, Decl(typeGuardAccordingToProperty.ts, 31, 19))
+
+    sy1: number;
+>sy1 : Symbol(Symbol1.sy1, Decl(typeGuardAccordingToProperty.ts, 32, 16))
+}
+
+interface Undefined1 {
+>Undefined1 : Symbol(Undefined1, Decl(typeGuardAccordingToProperty.ts, 34, 1))
+
+    key: undefined;
+>key : Symbol(Undefined1.key, Decl(typeGuardAccordingToProperty.ts, 36, 22))
+
+    u1: number;
+>u1 : Symbol(Undefined1.u1, Decl(typeGuardAccordingToProperty.ts, 37, 19))
+}
+
+interface Function1 {
+>Function1 : Symbol(Function1, Decl(typeGuardAccordingToProperty.ts, 39, 1))
+
+    key: () => void;
+>key : Symbol(Function1.key, Decl(typeGuardAccordingToProperty.ts, 41, 21))
+
+    f1: number;
+>f1 : Symbol(Function1.f1, Decl(typeGuardAccordingToProperty.ts, 42, 20))
+}
+
+interface Obejct1 {
+>Obejct1 : Symbol(Obejct1, Decl(typeGuardAccordingToProperty.ts, 44, 1))
+
+    key: {
+>key : Symbol(Obejct1.key, Decl(typeGuardAccordingToProperty.ts, 46, 19))
+
+        notEmpty: number;
+>notEmpty : Symbol(notEmpty, Decl(typeGuardAccordingToProperty.ts, 47, 10))
+
+    };
+    o1: number;
+>o1 : Symbol(Obejct1.o1, Decl(typeGuardAccordingToProperty.ts, 49, 6))
+}
+
+type Union1 = Boolean1 | Boolean2 | Number1;
+>Union1 : Symbol(Union1, Decl(typeGuardAccordingToProperty.ts, 51, 1))
+>Boolean1 : Symbol(Boolean1, Decl(typeGuardAccordingToProperty.ts, 0, 0))
+>Boolean2 : Symbol(Boolean2, Decl(typeGuardAccordingToProperty.ts, 9, 2))
+>Number1 : Symbol(Number1, Decl(typeGuardAccordingToProperty.ts, 19, 2))
+
+type Union2 = Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1;
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+>Boolean1 : Symbol(Boolean1, Decl(typeGuardAccordingToProperty.ts, 0, 0))
+>BigInt1 : Symbol(BigInt1, Decl(typeGuardAccordingToProperty.ts, 14, 2))
+>Number1 : Symbol(Number1, Decl(typeGuardAccordingToProperty.ts, 19, 2))
+>String1 : Symbol(String1, Decl(typeGuardAccordingToProperty.ts, 24, 2))
+>Symbol1 : Symbol(Symbol1, Decl(typeGuardAccordingToProperty.ts, 29, 1))
+>Undefined1 : Symbol(Undefined1, Decl(typeGuardAccordingToProperty.ts, 34, 1))
+>Function1 : Symbol(Function1, Decl(typeGuardAccordingToProperty.ts, 39, 1))
+>Obejct1 : Symbol(Obejct1, Decl(typeGuardAccordingToProperty.ts, 44, 1))
+
+function f1_1(u: Union1) {
+>f1_1 : Symbol(f1_1, Decl(typeGuardAccordingToProperty.ts, 54, 98))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 56, 14))
+>Union1 : Symbol(Union1, Decl(typeGuardAccordingToProperty.ts, 51, 1))
+
+    if (typeof u.key !== 'boolean') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 11, 20), Decl(typeGuardAccordingToProperty.ts, 21, 19))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 56, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 11, 20), Decl(typeGuardAccordingToProperty.ts, 21, 19))
+
+        u;      // Number1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 56, 14))
+
+        u.n1;   // number
+>u.n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToProperty.ts, 22, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 56, 14))
+>n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToProperty.ts, 22, 16))
+    }
+}
+function f1_2(u: Union1) {
+>f1_2 : Symbol(f1_2, Decl(typeGuardAccordingToProperty.ts, 61, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 62, 14))
+>Union1 : Symbol(Union1, Decl(typeGuardAccordingToProperty.ts, 51, 1))
+
+    if (typeof u.key === 'boolean') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 11, 20), Decl(typeGuardAccordingToProperty.ts, 21, 19))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 62, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 11, 20), Decl(typeGuardAccordingToProperty.ts, 21, 19))
+
+        u;      // Bolean1 | Bolean2
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 62, 14))
+
+        u.b1;   // Error
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 62, 14))
+
+        u.b2;   // Error
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 62, 14))
+    }
+}
+
+function f1ElementAccess_1(u: Union1) {
+>f1ElementAccess_1 : Symbol(f1ElementAccess_1, Decl(typeGuardAccordingToProperty.ts, 68, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 70, 27))
+>Union1 : Symbol(Union1, Decl(typeGuardAccordingToProperty.ts, 51, 1))
+
+    if (typeof u["key"] !== 'boolean') {
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 70, 27))
+>"key" : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 11, 20), Decl(typeGuardAccordingToProperty.ts, 21, 19))
+
+        u;      // Number1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 70, 27))
+
+        u.n1;   // number
+>u.n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToProperty.ts, 22, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 70, 27))
+>n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToProperty.ts, 22, 16))
+    }
+}
+function f1ElementAccess_2(u: Union1) {
+>f1ElementAccess_2 : Symbol(f1ElementAccess_2, Decl(typeGuardAccordingToProperty.ts, 75, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 76, 27))
+>Union1 : Symbol(Union1, Decl(typeGuardAccordingToProperty.ts, 51, 1))
+
+    if (typeof u["key"] === 'boolean') {
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 76, 27))
+>"key" : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 11, 20), Decl(typeGuardAccordingToProperty.ts, 21, 19))
+
+        u;      // Bolean1 | Bolean2
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 76, 27))
+
+        u.b1;   // Error
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 76, 27))
+
+        u.b2;   // Error
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 76, 27))
+    }
+}
+
+function f1_Plus(u: Union1) {
+>f1_Plus : Symbol(f1_Plus, Decl(typeGuardAccordingToProperty.ts, 82, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 84, 17))
+>Union1 : Symbol(Union1, Decl(typeGuardAccordingToProperty.ts, 51, 1))
+
+    if (typeof u.key !== 'boolean') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 11, 20), Decl(typeGuardAccordingToProperty.ts, 21, 19))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 84, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 11, 20), Decl(typeGuardAccordingToProperty.ts, 21, 19))
+
+        throw new Error();
+>Error : Symbol(Error, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+    }
+    u;  // Bolean1 | Bolean2
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 84, 17))
+
+    if (typeof u.key === 'boolean') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 11, 20))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 84, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 11, 20))
+
+        throw new Error();
+>Error : Symbol(Error, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+    }
+    u;  // never
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 84, 17))
+}
+
+// boolean bigint number string symbol undefined function object
+function f2_1(u: Union2) {
+>f2_1 : Symbol(f2_1, Decl(typeGuardAccordingToProperty.ts, 93, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 96, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key === 'bigint') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 96, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // BigInt1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 96, 14))
+
+        u.bi1;
+>u.bi1 : Symbol(BigInt1.bi1, Decl(typeGuardAccordingToProperty.ts, 17, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 96, 14))
+>bi1 : Symbol(BigInt1.bi1, Decl(typeGuardAccordingToProperty.ts, 17, 16))
+    }
+    if (typeof u.key == 'bigint') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 96, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // BigInt1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 96, 14))
+
+        u.bi1;
+>u.bi1 : Symbol(BigInt1.bi1, Decl(typeGuardAccordingToProperty.ts, 17, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 96, 14))
+>bi1 : Symbol(BigInt1.bi1, Decl(typeGuardAccordingToProperty.ts, 17, 16))
+    }
+}
+function f2_2(u: Union2) {
+>f2_2 : Symbol(f2_2, Decl(typeGuardAccordingToProperty.ts, 105, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 106, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key === 'boolean') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 106, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Boolean1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 106, 14))
+
+        u.b1;
+>u.b1 : Symbol(Boolean1.b1, Decl(typeGuardAccordingToProperty.ts, 7, 17))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 106, 14))
+>b1 : Symbol(Boolean1.b1, Decl(typeGuardAccordingToProperty.ts, 7, 17))
+    }
+    if (typeof u.key == 'boolean') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 106, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Boolean1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 106, 14))
+
+        u.b1;
+>u.b1 : Symbol(Boolean1.b1, Decl(typeGuardAccordingToProperty.ts, 7, 17))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 106, 14))
+>b1 : Symbol(Boolean1.b1, Decl(typeGuardAccordingToProperty.ts, 7, 17))
+    }
+}
+function f2_3(u: Union2) {
+>f2_3 : Symbol(f2_3, Decl(typeGuardAccordingToProperty.ts, 115, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 116, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key === 'number') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 116, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Number1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 116, 14))
+
+        u.n1;
+>u.n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToProperty.ts, 22, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 116, 14))
+>n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToProperty.ts, 22, 16))
+    }
+    if (typeof u.key == 'number') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 116, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Number1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 116, 14))
+
+        u.n1;
+>u.n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToProperty.ts, 22, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 116, 14))
+>n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToProperty.ts, 22, 16))
+    }
+}
+function f2_4(u: Union2) {
+>f2_4 : Symbol(f2_4, Decl(typeGuardAccordingToProperty.ts, 125, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 126, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key === 'string') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 126, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // String1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 126, 14))
+
+        u.st1;
+>u.st1 : Symbol(String1.st1, Decl(typeGuardAccordingToProperty.ts, 27, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 126, 14))
+>st1 : Symbol(String1.st1, Decl(typeGuardAccordingToProperty.ts, 27, 16))
+    }
+    if (typeof u.key == 'string') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 126, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // String1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 126, 14))
+
+        u.st1;
+>u.st1 : Symbol(String1.st1, Decl(typeGuardAccordingToProperty.ts, 27, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 126, 14))
+>st1 : Symbol(String1.st1, Decl(typeGuardAccordingToProperty.ts, 27, 16))
+    }
+}
+function f2_5(u: Union2) {
+>f2_5 : Symbol(f2_5, Decl(typeGuardAccordingToProperty.ts, 135, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 136, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key === 'symbol') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 136, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Symbol1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 136, 14))
+
+        u.sy1;
+>u.sy1 : Symbol(Symbol1.sy1, Decl(typeGuardAccordingToProperty.ts, 32, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 136, 14))
+>sy1 : Symbol(Symbol1.sy1, Decl(typeGuardAccordingToProperty.ts, 32, 16))
+    }
+    if (typeof u.key == 'symbol') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 136, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Symbol1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 136, 14))
+
+        u.sy1;
+>u.sy1 : Symbol(Symbol1.sy1, Decl(typeGuardAccordingToProperty.ts, 32, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 136, 14))
+>sy1 : Symbol(Symbol1.sy1, Decl(typeGuardAccordingToProperty.ts, 32, 16))
+    }
+}
+function f2_6(u: Union2) {
+>f2_6 : Symbol(f2_6, Decl(typeGuardAccordingToProperty.ts, 145, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 146, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key === 'undefined') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 146, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Undefined1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 146, 14))
+
+        u.u1
+>u.u1 : Symbol(Undefined1.u1, Decl(typeGuardAccordingToProperty.ts, 37, 19))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 146, 14))
+>u1 : Symbol(Undefined1.u1, Decl(typeGuardAccordingToProperty.ts, 37, 19))
+    }
+    if (typeof u.key == 'undefined') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 146, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Undefined1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 146, 14))
+
+        u.u1
+>u.u1 : Symbol(Undefined1.u1, Decl(typeGuardAccordingToProperty.ts, 37, 19))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 146, 14))
+>u1 : Symbol(Undefined1.u1, Decl(typeGuardAccordingToProperty.ts, 37, 19))
+    }
+}
+function f2_7(u: Union2) {
+>f2_7 : Symbol(f2_7, Decl(typeGuardAccordingToProperty.ts, 155, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 156, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key === 'function') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 156, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Function1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 156, 14))
+
+        u.f1;
+>u.f1 : Symbol(Function1.f1, Decl(typeGuardAccordingToProperty.ts, 42, 20))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 156, 14))
+>f1 : Symbol(Function1.f1, Decl(typeGuardAccordingToProperty.ts, 42, 20))
+    }
+    if (typeof u.key == 'function') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 156, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Function1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 156, 14))
+
+        u.f1;
+>u.f1 : Symbol(Function1.f1, Decl(typeGuardAccordingToProperty.ts, 42, 20))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 156, 14))
+>f1 : Symbol(Function1.f1, Decl(typeGuardAccordingToProperty.ts, 42, 20))
+    }
+}
+function f2_8(u: Union2) {
+>f2_8 : Symbol(f2_8, Decl(typeGuardAccordingToProperty.ts, 165, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 166, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key === 'object') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 166, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Object1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 166, 14))
+
+        u.o1;
+>u.o1 : Symbol(Obejct1.o1, Decl(typeGuardAccordingToProperty.ts, 49, 6))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 166, 14))
+>o1 : Symbol(Obejct1.o1, Decl(typeGuardAccordingToProperty.ts, 49, 6))
+    }
+    if (typeof u.key == 'object') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 166, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // Object1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 166, 14))
+
+        u.o1;
+>u.o1 : Symbol(Obejct1.o1, Decl(typeGuardAccordingToProperty.ts, 49, 6))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 166, 14))
+>o1 : Symbol(Obejct1.o1, Decl(typeGuardAccordingToProperty.ts, 49, 6))
+    }
+}
+
+function f2Not_1(u: Union2) {
+>f2Not_1 : Symbol(f2Not_1, Decl(typeGuardAccordingToProperty.ts, 175, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 177, 17))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key !== 'bigint') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 177, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not BigInt1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 177, 17))
+    }
+    if (typeof u.key != 'bigint') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 177, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not BigInt1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 177, 17))
+    }
+}
+function f2Not_2(u: Union2) {
+>f2Not_2 : Symbol(f2Not_2, Decl(typeGuardAccordingToProperty.ts, 184, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 185, 17))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key !== 'boolean') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 185, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Boolean1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 185, 17))
+    }
+    if (typeof u.key != 'boolean') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 185, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Boolean1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 185, 17))
+    }
+}
+
+function f2Not_3(u: Union2) {
+>f2Not_3 : Symbol(f2Not_3, Decl(typeGuardAccordingToProperty.ts, 192, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 194, 17))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key !== 'number') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 194, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Number1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 194, 17))
+    }
+    if (typeof u.key != 'number') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 194, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Number1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 194, 17))
+    }
+}
+
+function f2Not_4(u: Union2) {
+>f2Not_4 : Symbol(f2Not_4, Decl(typeGuardAccordingToProperty.ts, 201, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 203, 17))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key !== 'string') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 203, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not String1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 203, 17))
+    }
+    if (typeof u.key != 'string') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 203, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not String1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 203, 17))
+    }
+}
+
+function f2Not_5(u: Union2) {
+>f2Not_5 : Symbol(f2Not_5, Decl(typeGuardAccordingToProperty.ts, 210, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 212, 17))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key !== 'symbol') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 212, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Symbol1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 212, 17))
+    }
+    if (typeof u.key != 'symbol') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 212, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Symbol1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 212, 17))
+    }
+}
+
+function f2Not_6(u: Union2) {
+>f2Not_6 : Symbol(f2Not_6, Decl(typeGuardAccordingToProperty.ts, 219, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 221, 17))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key !== 'undefined') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 221, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Undefined1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 221, 17))
+    }
+    if (typeof u.key != 'undefined') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 221, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Undefined1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 221, 17))
+    }
+}
+
+function f2Not_7(u: Union2) {
+>f2Not_7 : Symbol(f2Not_7, Decl(typeGuardAccordingToProperty.ts, 228, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 230, 17))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key !== 'function') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 230, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Function1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 230, 17))
+    }
+    if (typeof u.key != 'function') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 230, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Function1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 230, 17))
+    }
+}
+
+function f2Not_8(u: Union2) {
+>f2Not_8 : Symbol(f2Not_8, Decl(typeGuardAccordingToProperty.ts, 237, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 239, 17))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToProperty.ts, 53, 44))
+
+    if (typeof u.key !== 'object') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 239, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Object1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 239, 17))
+    }
+    if (typeof u.key != 'object') {
+>u.key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 239, 17))
+>key : Symbol(key, Decl(typeGuardAccordingToProperty.ts, 6, 20), Decl(typeGuardAccordingToProperty.ts, 16, 19), Decl(typeGuardAccordingToProperty.ts, 21, 19), Decl(typeGuardAccordingToProperty.ts, 26, 19), Decl(typeGuardAccordingToProperty.ts, 31, 19) ... and 3 more)
+
+        u;      // not Object1
+>u : Symbol(u, Decl(typeGuardAccordingToProperty.ts, 239, 17))
+    }
+}
+
+interface A { x: string, y: string };
+>A : Symbol(A, Decl(typeGuardAccordingToProperty.ts, 246, 1))
+>x : Symbol(A.x, Decl(typeGuardAccordingToProperty.ts, 248, 13))
+>y : Symbol(A.y, Decl(typeGuardAccordingToProperty.ts, 248, 24))
+
+interface B { x: number, y: number };
+>B : Symbol(B, Decl(typeGuardAccordingToProperty.ts, 248, 37))
+>x : Symbol(B.x, Decl(typeGuardAccordingToProperty.ts, 249, 13))
+>y : Symbol(B.y, Decl(typeGuardAccordingToProperty.ts, 249, 24))
+
+type X = A | B;
+>X : Symbol(X, Decl(typeGuardAccordingToProperty.ts, 249, 37))
+>A : Symbol(A, Decl(typeGuardAccordingToProperty.ts, 246, 1))
+>B : Symbol(B, Decl(typeGuardAccordingToProperty.ts, 248, 37))
+
+function f3(bar: X) {
+>f3 : Symbol(f3, Decl(typeGuardAccordingToProperty.ts, 250, 15))
+>bar : Symbol(bar, Decl(typeGuardAccordingToProperty.ts, 252, 12))
+>X : Symbol(X, Decl(typeGuardAccordingToProperty.ts, 249, 37))
+
+    if (typeof bar.x === 'string') {
+>bar.x : Symbol(x, Decl(typeGuardAccordingToProperty.ts, 248, 13), Decl(typeGuardAccordingToProperty.ts, 249, 13))
+>bar : Symbol(bar, Decl(typeGuardAccordingToProperty.ts, 252, 12))
+>x : Symbol(x, Decl(typeGuardAccordingToProperty.ts, 248, 13), Decl(typeGuardAccordingToProperty.ts, 249, 13))
+
+        let y = bar.y; // string
+>y : Symbol(y, Decl(typeGuardAccordingToProperty.ts, 254, 11))
+>bar.y : Symbol(A.y, Decl(typeGuardAccordingToProperty.ts, 248, 24))
+>bar : Symbol(bar, Decl(typeGuardAccordingToProperty.ts, 252, 12))
+>y : Symbol(A.y, Decl(typeGuardAccordingToProperty.ts, 248, 24))
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToProperty.types b/tests/baselines/reference/typeGuardAccordingToProperty.types
new file mode 100644
index 0000000000000..92bc6a209329e
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToProperty.types
@@ -0,0 +1,776 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty.ts ===
+// Primitive value ---- boolean bigint number string symbol undefined function object
+// ts special type ---- any, void, unknown, union, intersection
+
+//// Property Access ---- a.b
+//// Element Access ---- a["b"]
+
+interface Boolean1 {
+    key: boolean;
+>key : boolean
+
+    b1: number;
+>b1 : number
+
+};
+
+interface Boolean2 {
+    key: boolean;
+>key : boolean
+
+    b2: number;
+>b2 : number
+
+};
+
+interface BigInt1 {
+    key: bigint;
+>key : bigint
+
+    bi1: number;
+>bi1 : number
+
+};
+
+interface Number1 {
+    key: number;
+>key : number
+
+    n1: number;
+>n1 : number
+
+};
+
+interface String1 {
+    key: string;
+>key : string
+
+    st1: number;
+>st1 : number
+}
+
+interface Symbol1 {
+    key: symbol;
+>key : symbol
+
+    sy1: number;
+>sy1 : number
+}
+
+interface Undefined1 {
+    key: undefined;
+>key : undefined
+
+    u1: number;
+>u1 : number
+}
+
+interface Function1 {
+    key: () => void;
+>key : () => void
+
+    f1: number;
+>f1 : number
+}
+
+interface Obejct1 {
+    key: {
+>key : { notEmpty: number; }
+
+        notEmpty: number;
+>notEmpty : number
+
+    };
+    o1: number;
+>o1 : number
+}
+
+type Union1 = Boolean1 | Boolean2 | Number1;
+>Union1 : Union1
+
+type Union2 = Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1;
+>Union2 : Union2
+
+function f1_1(u: Union1) {
+>f1_1 : (u: Union1) => void
+>u : Union1
+
+    if (typeof u.key !== 'boolean') {
+>typeof u.key !== 'boolean' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : number | boolean
+>u : Union1
+>key : number | boolean
+>'boolean' : "boolean"
+
+        u;      // Number1
+>u : Number1
+
+        u.n1;   // number
+>u.n1 : number
+>u : Number1
+>n1 : number
+    }
+}
+function f1_2(u: Union1) {
+>f1_2 : (u: Union1) => void
+>u : Union1
+
+    if (typeof u.key === 'boolean') {
+>typeof u.key === 'boolean' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : number | boolean
+>u : Union1
+>key : number | boolean
+>'boolean' : "boolean"
+
+        u;      // Bolean1 | Bolean2
+>u : Boolean1 | Boolean2
+
+        u.b1;   // Error
+>u.b1 : any
+>u : Boolean1 | Boolean2
+>b1 : any
+
+        u.b2;   // Error
+>u.b2 : any
+>u : Boolean1 | Boolean2
+>b2 : any
+    }
+}
+
+function f1ElementAccess_1(u: Union1) {
+>f1ElementAccess_1 : (u: Union1) => void
+>u : Union1
+
+    if (typeof u["key"] !== 'boolean') {
+>typeof u["key"] !== 'boolean' : boolean
+>typeof u["key"] : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u["key"] : number | boolean
+>u : Union1
+>"key" : "key"
+>'boolean' : "boolean"
+
+        u;      // Number1
+>u : Number1
+
+        u.n1;   // number
+>u.n1 : number
+>u : Number1
+>n1 : number
+    }
+}
+function f1ElementAccess_2(u: Union1) {
+>f1ElementAccess_2 : (u: Union1) => void
+>u : Union1
+
+    if (typeof u["key"] === 'boolean') {
+>typeof u["key"] === 'boolean' : boolean
+>typeof u["key"] : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u["key"] : number | boolean
+>u : Union1
+>"key" : "key"
+>'boolean' : "boolean"
+
+        u;      // Bolean1 | Bolean2
+>u : Boolean1 | Boolean2
+
+        u.b1;   // Error
+>u.b1 : any
+>u : Boolean1 | Boolean2
+>b1 : any
+
+        u.b2;   // Error
+>u.b2 : any
+>u : Boolean1 | Boolean2
+>b2 : any
+    }
+}
+
+function f1_Plus(u: Union1) {
+>f1_Plus : (u: Union1) => void
+>u : Union1
+
+    if (typeof u.key !== 'boolean') {
+>typeof u.key !== 'boolean' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : number | boolean
+>u : Union1
+>key : number | boolean
+>'boolean' : "boolean"
+
+        throw new Error();
+>new Error() : Error
+>Error : ErrorConstructor
+    }
+    u;  // Bolean1 | Bolean2
+>u : Boolean1 | Boolean2
+
+    if (typeof u.key === 'boolean') {
+>typeof u.key === 'boolean' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : boolean
+>u : Boolean1 | Boolean2
+>key : boolean
+>'boolean' : "boolean"
+
+        throw new Error();
+>new Error() : Error
+>Error : ErrorConstructor
+    }
+    u;  // never
+>u : never
+}
+
+// boolean bigint number string symbol undefined function object
+function f2_1(u: Union2) {
+>f2_1 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key === 'bigint') {
+>typeof u.key === 'bigint' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'bigint' : "bigint"
+
+        u;      // BigInt1
+>u : BigInt1
+
+        u.bi1;
+>u.bi1 : number
+>u : BigInt1
+>bi1 : number
+    }
+    if (typeof u.key == 'bigint') {
+>typeof u.key == 'bigint' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'bigint' : "bigint"
+
+        u;      // BigInt1
+>u : BigInt1
+
+        u.bi1;
+>u.bi1 : number
+>u : BigInt1
+>bi1 : number
+    }
+}
+function f2_2(u: Union2) {
+>f2_2 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key === 'boolean') {
+>typeof u.key === 'boolean' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'boolean' : "boolean"
+
+        u;      // Boolean1
+>u : Boolean1
+
+        u.b1;
+>u.b1 : number
+>u : Boolean1
+>b1 : number
+    }
+    if (typeof u.key == 'boolean') {
+>typeof u.key == 'boolean' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'boolean' : "boolean"
+
+        u;      // Boolean1
+>u : Boolean1
+
+        u.b1;
+>u.b1 : number
+>u : Boolean1
+>b1 : number
+    }
+}
+function f2_3(u: Union2) {
+>f2_3 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key === 'number') {
+>typeof u.key === 'number' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'number' : "number"
+
+        u;      // Number1
+>u : Number1
+
+        u.n1;
+>u.n1 : number
+>u : Number1
+>n1 : number
+    }
+    if (typeof u.key == 'number') {
+>typeof u.key == 'number' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'number' : "number"
+
+        u;      // Number1
+>u : Number1
+
+        u.n1;
+>u.n1 : number
+>u : Number1
+>n1 : number
+    }
+}
+function f2_4(u: Union2) {
+>f2_4 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key === 'string') {
+>typeof u.key === 'string' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'string' : "string"
+
+        u;      // String1
+>u : String1
+
+        u.st1;
+>u.st1 : number
+>u : String1
+>st1 : number
+    }
+    if (typeof u.key == 'string') {
+>typeof u.key == 'string' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'string' : "string"
+
+        u;      // String1
+>u : String1
+
+        u.st1;
+>u.st1 : number
+>u : String1
+>st1 : number
+    }
+}
+function f2_5(u: Union2) {
+>f2_5 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key === 'symbol') {
+>typeof u.key === 'symbol' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'symbol' : "symbol"
+
+        u;      // Symbol1
+>u : Symbol1
+
+        u.sy1;
+>u.sy1 : number
+>u : Symbol1
+>sy1 : number
+    }
+    if (typeof u.key == 'symbol') {
+>typeof u.key == 'symbol' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'symbol' : "symbol"
+
+        u;      // Symbol1
+>u : Symbol1
+
+        u.sy1;
+>u.sy1 : number
+>u : Symbol1
+>sy1 : number
+    }
+}
+function f2_6(u: Union2) {
+>f2_6 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key === 'undefined') {
+>typeof u.key === 'undefined' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'undefined' : "undefined"
+
+        u;      // Undefined1
+>u : Undefined1
+
+        u.u1
+>u.u1 : number
+>u : Undefined1
+>u1 : number
+    }
+    if (typeof u.key == 'undefined') {
+>typeof u.key == 'undefined' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'undefined' : "undefined"
+
+        u;      // Undefined1
+>u : Undefined1
+
+        u.u1
+>u.u1 : number
+>u : Undefined1
+>u1 : number
+    }
+}
+function f2_7(u: Union2) {
+>f2_7 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key === 'function') {
+>typeof u.key === 'function' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'function' : "function"
+
+        u;      // Function1
+>u : Function1
+
+        u.f1;
+>u.f1 : number
+>u : Function1
+>f1 : number
+    }
+    if (typeof u.key == 'function') {
+>typeof u.key == 'function' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'function' : "function"
+
+        u;      // Function1
+>u : Function1
+
+        u.f1;
+>u.f1 : number
+>u : Function1
+>f1 : number
+    }
+}
+function f2_8(u: Union2) {
+>f2_8 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key === 'object') {
+>typeof u.key === 'object' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'object' : "object"
+
+        u;      // Object1
+>u : Obejct1
+
+        u.o1;
+>u.o1 : number
+>u : Obejct1
+>o1 : number
+    }
+    if (typeof u.key == 'object') {
+>typeof u.key == 'object' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'object' : "object"
+
+        u;      // Object1
+>u : Obejct1
+
+        u.o1;
+>u.o1 : number
+>u : Obejct1
+>o1 : number
+    }
+}
+
+function f2Not_1(u: Union2) {
+>f2Not_1 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key !== 'bigint') {
+>typeof u.key !== 'bigint' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'bigint' : "bigint"
+
+        u;      // not BigInt1
+>u : Boolean1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1
+    }
+    if (typeof u.key != 'bigint') {
+>typeof u.key != 'bigint' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'bigint' : "bigint"
+
+        u;      // not BigInt1
+>u : Boolean1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1
+    }
+}
+function f2Not_2(u: Union2) {
+>f2Not_2 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key !== 'boolean') {
+>typeof u.key !== 'boolean' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'boolean' : "boolean"
+
+        u;      // not Boolean1
+>u : BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1
+    }
+    if (typeof u.key != 'boolean') {
+>typeof u.key != 'boolean' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'boolean' : "boolean"
+
+        u;      // not Boolean1
+>u : BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1
+    }
+}
+
+function f2Not_3(u: Union2) {
+>f2Not_3 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key !== 'number') {
+>typeof u.key !== 'number' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'number' : "number"
+
+        u;      // not Number1
+>u : Boolean1 | BigInt1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1
+    }
+    if (typeof u.key != 'number') {
+>typeof u.key != 'number' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'number' : "number"
+
+        u;      // not Number1
+>u : Boolean1 | BigInt1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1
+    }
+}
+
+function f2Not_4(u: Union2) {
+>f2Not_4 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key !== 'string') {
+>typeof u.key !== 'string' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'string' : "string"
+
+        u;      // not String1
+>u : Boolean1 | BigInt1 | Number1 | Symbol1 | Undefined1 | Function1 | Obejct1
+    }
+    if (typeof u.key != 'string') {
+>typeof u.key != 'string' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'string' : "string"
+
+        u;      // not String1
+>u : Boolean1 | BigInt1 | Number1 | Symbol1 | Undefined1 | Function1 | Obejct1
+    }
+}
+
+function f2Not_5(u: Union2) {
+>f2Not_5 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key !== 'symbol') {
+>typeof u.key !== 'symbol' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'symbol' : "symbol"
+
+        u;      // not Symbol1
+>u : Boolean1 | BigInt1 | Number1 | String1 | Undefined1 | Function1 | Obejct1
+    }
+    if (typeof u.key != 'symbol') {
+>typeof u.key != 'symbol' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'symbol' : "symbol"
+
+        u;      // not Symbol1
+>u : Boolean1 | BigInt1 | Number1 | String1 | Undefined1 | Function1 | Obejct1
+    }
+}
+
+function f2Not_6(u: Union2) {
+>f2Not_6 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key !== 'undefined') {
+>typeof u.key !== 'undefined' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'undefined' : "undefined"
+
+        u;      // not Undefined1
+>u : Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Function1 | Obejct1
+    }
+    if (typeof u.key != 'undefined') {
+>typeof u.key != 'undefined' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'undefined' : "undefined"
+
+        u;      // not Undefined1
+>u : Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Function1 | Obejct1
+    }
+}
+
+function f2Not_7(u: Union2) {
+>f2Not_7 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key !== 'function') {
+>typeof u.key !== 'function' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'function' : "function"
+
+        u;      // not Function1
+>u : Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Obejct1
+    }
+    if (typeof u.key != 'function') {
+>typeof u.key != 'function' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'function' : "function"
+
+        u;      // not Function1
+>u : Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Obejct1
+    }
+}
+
+function f2Not_8(u: Union2) {
+>f2Not_8 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.key !== 'object') {
+>typeof u.key !== 'object' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'object' : "object"
+
+        u;      // not Object1
+>u : Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1
+    }
+    if (typeof u.key != 'object') {
+>typeof u.key != 'object' : boolean
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>'object' : "object"
+
+        u;      // not Object1
+>u : Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1
+    }
+}
+
+interface A { x: string, y: string };
+>x : string
+>y : string
+
+interface B { x: number, y: number };
+>x : number
+>y : number
+
+type X = A | B;
+>X : X
+
+function f3(bar: X) {
+>f3 : (bar: X) => void
+>bar : X
+
+    if (typeof bar.x === 'string') {
+>typeof bar.x === 'string' : boolean
+>typeof bar.x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>bar.x : string | number
+>bar : X
+>x : string | number
+>'string' : "string"
+
+        let y = bar.y; // string
+>y : string
+>bar.y : string
+>bar : A
+>y : string
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToProperty2.js b/tests/baselines/reference/typeGuardAccordingToProperty2.js
new file mode 100644
index 0000000000000..b2d69a36d474f
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToProperty2.js
@@ -0,0 +1,43 @@
+//// [typeGuardAccordingToProperty2.ts]
+interface A {
+    kind: 'A';
+    symbol: object;
+    fileName: string;
+}
+
+interface B {
+    kind: 'B';
+}
+
+declare var s: A | B;
+
+if (s.kind === 'A') {
+    if (s.symbol) {     // this is a truthy condition, we could narrow it, but it has a property `symbol`, so do nothing.
+        s;    // A
+    } else {
+        s.fileName;  // A
+    }
+
+    if (s) {    // this is another truthy condition, now it is alone, so narrow it.
+        s; // A
+    } else {
+        s; // never
+    }
+}
+
+//// [typeGuardAccordingToProperty2.js]
+"use strict";
+if (s.kind === 'A') {
+    if (s.symbol) { // this is a truthy condition, we could narrow it, but it has a property `symbol`, so do nothing.
+        s; // A
+    }
+    else {
+        s.fileName; // A
+    }
+    if (s) { // this is another truthy condition, now it is alone, so narrow it.
+        s; // A
+    }
+    else {
+        s; // never
+    }
+}
diff --git a/tests/baselines/reference/typeGuardAccordingToProperty2.symbols b/tests/baselines/reference/typeGuardAccordingToProperty2.symbols
new file mode 100644
index 0000000000000..7330725c2c876
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToProperty2.symbols
@@ -0,0 +1,57 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty2.ts ===
+interface A {
+>A : Symbol(A, Decl(typeGuardAccordingToProperty2.ts, 0, 0))
+
+    kind: 'A';
+>kind : Symbol(A.kind, Decl(typeGuardAccordingToProperty2.ts, 0, 13))
+
+    symbol: object;
+>symbol : Symbol(A.symbol, Decl(typeGuardAccordingToProperty2.ts, 1, 14))
+
+    fileName: string;
+>fileName : Symbol(A.fileName, Decl(typeGuardAccordingToProperty2.ts, 2, 19))
+}
+
+interface B {
+>B : Symbol(B, Decl(typeGuardAccordingToProperty2.ts, 4, 1))
+
+    kind: 'B';
+>kind : Symbol(B.kind, Decl(typeGuardAccordingToProperty2.ts, 6, 13))
+}
+
+declare var s: A | B;
+>s : Symbol(s, Decl(typeGuardAccordingToProperty2.ts, 10, 11))
+>A : Symbol(A, Decl(typeGuardAccordingToProperty2.ts, 0, 0))
+>B : Symbol(B, Decl(typeGuardAccordingToProperty2.ts, 4, 1))
+
+if (s.kind === 'A') {
+>s.kind : Symbol(kind, Decl(typeGuardAccordingToProperty2.ts, 0, 13), Decl(typeGuardAccordingToProperty2.ts, 6, 13))
+>s : Symbol(s, Decl(typeGuardAccordingToProperty2.ts, 10, 11))
+>kind : Symbol(kind, Decl(typeGuardAccordingToProperty2.ts, 0, 13), Decl(typeGuardAccordingToProperty2.ts, 6, 13))
+
+    if (s.symbol) {     // this is a truthy condition, we could narrow it, but it has a property `symbol`, so do nothing.
+>s.symbol : Symbol(A.symbol, Decl(typeGuardAccordingToProperty2.ts, 1, 14))
+>s : Symbol(s, Decl(typeGuardAccordingToProperty2.ts, 10, 11))
+>symbol : Symbol(A.symbol, Decl(typeGuardAccordingToProperty2.ts, 1, 14))
+
+        s;    // A
+>s : Symbol(s, Decl(typeGuardAccordingToProperty2.ts, 10, 11))
+
+    } else {
+        s.fileName;  // A
+>s.fileName : Symbol(A.fileName, Decl(typeGuardAccordingToProperty2.ts, 2, 19))
+>s : Symbol(s, Decl(typeGuardAccordingToProperty2.ts, 10, 11))
+>fileName : Symbol(A.fileName, Decl(typeGuardAccordingToProperty2.ts, 2, 19))
+    }
+
+    if (s) {    // this is another truthy condition, now it is alone, so narrow it.
+>s : Symbol(s, Decl(typeGuardAccordingToProperty2.ts, 10, 11))
+
+        s; // A
+>s : Symbol(s, Decl(typeGuardAccordingToProperty2.ts, 10, 11))
+
+    } else {
+        s; // never
+>s : Symbol(s, Decl(typeGuardAccordingToProperty2.ts, 10, 11))
+    }
+}
diff --git a/tests/baselines/reference/typeGuardAccordingToProperty2.types b/tests/baselines/reference/typeGuardAccordingToProperty2.types
new file mode 100644
index 0000000000000..887dc5ea10091
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToProperty2.types
@@ -0,0 +1,53 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty2.ts ===
+interface A {
+    kind: 'A';
+>kind : "A"
+
+    symbol: object;
+>symbol : object
+
+    fileName: string;
+>fileName : string
+}
+
+interface B {
+    kind: 'B';
+>kind : "B"
+}
+
+declare var s: A | B;
+>s : A | B
+
+if (s.kind === 'A') {
+>s.kind === 'A' : boolean
+>s.kind : "A" | "B"
+>s : A | B
+>kind : "A" | "B"
+>'A' : "A"
+
+    if (s.symbol) {     // this is a truthy condition, we could narrow it, but it has a property `symbol`, so do nothing.
+>s.symbol : object
+>s : A
+>symbol : object
+
+        s;    // A
+>s : A
+
+    } else {
+        s.fileName;  // A
+>s.fileName : string
+>s : A
+>fileName : string
+    }
+
+    if (s) {    // this is another truthy condition, now it is alone, so narrow it.
+>s : A
+
+        s; // A
+>s : A
+
+    } else {
+        s; // never
+>s : never
+    }
+}
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyBySwitch.js b/tests/baselines/reference/typeGuardAccordingToPropertyBySwitch.js
new file mode 100644
index 0000000000000..4eace09749166
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyBySwitch.js
@@ -0,0 +1,301 @@
+//// [typeGuardAccordingToPropertyBySwitch.ts]
+// Primitive value ---- boolean bigint number string symbol undefined function object
+// ts special type ---- any, void, unknown, union, intersection
+
+//// Property Access ---- a.b
+//// Element Access ---- a["b"]
+
+interface Boolean1 {
+    key: boolean;
+    b1: number;
+};
+
+interface Boolean2 {
+    key: boolean;
+    b2: number;
+};
+
+interface BigInt1 {
+    key: bigint;
+    bi1: number;
+};
+
+interface Number1 {
+    key: number;
+    n1: number;
+};
+
+interface String1 {
+    key: string;
+    st1: number;
+}
+
+interface Symbol1 {
+    key: symbol;
+    sy1: number;
+}
+
+interface Undefined1 {
+    key: undefined;
+    u1: number;
+}
+
+interface Function1 {
+    key: () => void;
+    f1: number;
+}
+
+interface Obejct1 {
+    key: {
+        notEmpty: number;
+    };
+    o1: number;
+}
+
+type Union1 = Boolean1 | Boolean2 | Number1;
+type Union2 = Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1;
+
+function f1_1(u: Union1) {
+    switch (typeof u.key) {
+        case 'boolean':
+            u;    // Boolean1 | Boolean2
+            break;
+        case 'number':
+            u;    // Number1
+            break;
+        default:
+            u;    // never
+            break;
+    }
+}
+
+function f1_2(u: Union1) {
+    switch (typeof u.key) {
+        case 'boolean':
+            u;    // Boolean1 | Boolean2
+            break;
+        default:
+            u;    // Number1
+            break;
+    }
+}
+
+
+function f1ElementAccess_1(u: Union1) {
+    if (typeof u["key"] !== 'boolean') {
+        u;      // Number1
+        u.n1;   // number
+    }
+}
+
+// boolean bigint number string symbol undefined function object
+function f2_1(u: Union2) {
+    switch (typeof u.key) {
+        case 'bigint':
+            u;  // Bigint1
+            break;
+        case 'boolean':
+            u;  // Boolean1
+            break;
+        case 'number':
+            u;  // Number1
+            break;
+        case 'string':
+            u;  // String1
+            break;
+        case 'symbol':
+            u;  // Symbol1
+            break;
+        case 'undefined':
+            u;  // Undefined1
+            break;
+        case 'function':
+            u;  // Function1
+            break;
+        case 'object':
+            u;  // Object1
+            break;
+    }
+}
+
+function f2_2(u: Union2) {
+    switch (typeof u.key) {
+        case 'bigint':
+        case 'boolean':
+        case 'number':
+        case 'string':
+            u;  // Boolean1 | Number1 | BigInt1 | String1
+            break;
+        case 'symbol':
+        case 'undefined':
+        case 'function':
+        case 'object':
+            u;   // Symbol1 | Undefined1 | Function1 | Obejct1
+            break;
+    }
+}
+
+function f2_3(u: Union2) {
+    switch (typeof u.key) {
+        case 'bigint':
+        case 'boolean':
+        case 'number':
+        case 'string':
+            u;  // Boolean1 | Number1 | BigInt1 | String1
+            break;
+        default:
+            u;  // Symbol1 | Undefined1 | Function1 | Obejct1
+            break;
+    }
+}
+
+function f2_4(u: Union2) {
+    switch (typeof u.key) {
+        case 'symbol':
+        case 'undefined':
+        case 'function':
+        case 'object':
+            u;  // Symbol1 | Undefined1 | Function1 | Obejct1
+            break;
+        default:
+            u;  // Boolean1 | BigInt1 | Number1 | String1
+            break;
+    }
+}
+
+interface A { x: string, y: string };
+interface B { x: number, y: number };
+type X = A | B;
+
+function f3(bar: X) {
+    switch (typeof bar.x) {
+        case 'string':
+            let y = bar.y; // string
+            break;
+        default:
+            bar.y;
+            break;
+    }
+}
+
+
+//// [typeGuardAccordingToPropertyBySwitch.js]
+"use strict";
+// Primitive value ---- boolean bigint number string symbol undefined function object
+// ts special type ---- any, void, unknown, union, intersection
+;
+;
+;
+;
+function f1_1(u) {
+    switch (typeof u.key) {
+        case 'boolean':
+            u; // Boolean1 | Boolean2
+            break;
+        case 'number':
+            u; // Number1
+            break;
+        default:
+            u; // never
+            break;
+    }
+}
+function f1_2(u) {
+    switch (typeof u.key) {
+        case 'boolean':
+            u; // Boolean1 | Boolean2
+            break;
+        default:
+            u; // Number1
+            break;
+    }
+}
+function f1ElementAccess_1(u) {
+    if (typeof u["key"] !== 'boolean') {
+        u; // Number1
+        u.n1; // number
+    }
+}
+// boolean bigint number string symbol undefined function object
+function f2_1(u) {
+    switch (typeof u.key) {
+        case 'bigint':
+            u; // Bigint1
+            break;
+        case 'boolean':
+            u; // Boolean1
+            break;
+        case 'number':
+            u; // Number1
+            break;
+        case 'string':
+            u; // String1
+            break;
+        case 'symbol':
+            u; // Symbol1
+            break;
+        case 'undefined':
+            u; // Undefined1
+            break;
+        case 'function':
+            u; // Function1
+            break;
+        case 'object':
+            u; // Object1
+            break;
+    }
+}
+function f2_2(u) {
+    switch (typeof u.key) {
+        case 'bigint':
+        case 'boolean':
+        case 'number':
+        case 'string':
+            u; // Boolean1 | Number1 | BigInt1 | String1
+            break;
+        case 'symbol':
+        case 'undefined':
+        case 'function':
+        case 'object':
+            u; // Symbol1 | Undefined1 | Function1 | Obejct1
+            break;
+    }
+}
+function f2_3(u) {
+    switch (typeof u.key) {
+        case 'bigint':
+        case 'boolean':
+        case 'number':
+        case 'string':
+            u; // Boolean1 | Number1 | BigInt1 | String1
+            break;
+        default:
+            u; // Symbol1 | Undefined1 | Function1 | Obejct1
+            break;
+    }
+}
+function f2_4(u) {
+    switch (typeof u.key) {
+        case 'symbol':
+        case 'undefined':
+        case 'function':
+        case 'object':
+            u; // Symbol1 | Undefined1 | Function1 | Obejct1
+            break;
+        default:
+            u; // Boolean1 | BigInt1 | Number1 | String1
+            break;
+    }
+}
+;
+;
+function f3(bar) {
+    switch (typeof bar.x) {
+        case 'string':
+            var y = bar.y; // string
+            break;
+        default:
+            bar.y;
+            break;
+    }
+}
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyBySwitch.symbols b/tests/baselines/reference/typeGuardAccordingToPropertyBySwitch.symbols
new file mode 100644
index 0000000000000..c29805a791210
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyBySwitch.symbols
@@ -0,0 +1,371 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyBySwitch.ts ===
+// Primitive value ---- boolean bigint number string symbol undefined function object
+// ts special type ---- any, void, unknown, union, intersection
+
+//// Property Access ---- a.b
+//// Element Access ---- a["b"]
+
+interface Boolean1 {
+>Boolean1 : Symbol(Boolean1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 0, 0))
+
+    key: boolean;
+>key : Symbol(Boolean1.key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20))
+
+    b1: number;
+>b1 : Symbol(Boolean1.b1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 7, 17))
+
+};
+
+interface Boolean2 {
+>Boolean2 : Symbol(Boolean2, Decl(typeGuardAccordingToPropertyBySwitch.ts, 9, 2))
+
+    key: boolean;
+>key : Symbol(Boolean2.key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 11, 20))
+
+    b2: number;
+>b2 : Symbol(Boolean2.b2, Decl(typeGuardAccordingToPropertyBySwitch.ts, 12, 17))
+
+};
+
+interface BigInt1 {
+>BigInt1 : Symbol(BigInt1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 14, 2))
+
+    key: bigint;
+>key : Symbol(BigInt1.key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 16, 19))
+
+    bi1: number;
+>bi1 : Symbol(BigInt1.bi1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 17, 16))
+
+};
+
+interface Number1 {
+>Number1 : Symbol(Number1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 19, 2))
+
+    key: number;
+>key : Symbol(Number1.key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19))
+
+    n1: number;
+>n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 22, 16))
+
+};
+
+interface String1 {
+>String1 : Symbol(String1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 24, 2))
+
+    key: string;
+>key : Symbol(String1.key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 26, 19))
+
+    st1: number;
+>st1 : Symbol(String1.st1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 27, 16))
+}
+
+interface Symbol1 {
+>Symbol1 : Symbol(Symbol1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 29, 1))
+
+    key: symbol;
+>key : Symbol(Symbol1.key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 31, 19))
+
+    sy1: number;
+>sy1 : Symbol(Symbol1.sy1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 32, 16))
+}
+
+interface Undefined1 {
+>Undefined1 : Symbol(Undefined1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 34, 1))
+
+    key: undefined;
+>key : Symbol(Undefined1.key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 36, 22))
+
+    u1: number;
+>u1 : Symbol(Undefined1.u1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 37, 19))
+}
+
+interface Function1 {
+>Function1 : Symbol(Function1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 39, 1))
+
+    key: () => void;
+>key : Symbol(Function1.key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 41, 21))
+
+    f1: number;
+>f1 : Symbol(Function1.f1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 42, 20))
+}
+
+interface Obejct1 {
+>Obejct1 : Symbol(Obejct1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 44, 1))
+
+    key: {
+>key : Symbol(Obejct1.key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 46, 19))
+
+        notEmpty: number;
+>notEmpty : Symbol(notEmpty, Decl(typeGuardAccordingToPropertyBySwitch.ts, 47, 10))
+
+    };
+    o1: number;
+>o1 : Symbol(Obejct1.o1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 49, 6))
+}
+
+type Union1 = Boolean1 | Boolean2 | Number1;
+>Union1 : Symbol(Union1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 51, 1))
+>Boolean1 : Symbol(Boolean1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 0, 0))
+>Boolean2 : Symbol(Boolean2, Decl(typeGuardAccordingToPropertyBySwitch.ts, 9, 2))
+>Number1 : Symbol(Number1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 19, 2))
+
+type Union2 = Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1;
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyBySwitch.ts, 53, 44))
+>Boolean1 : Symbol(Boolean1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 0, 0))
+>BigInt1 : Symbol(BigInt1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 14, 2))
+>Number1 : Symbol(Number1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 19, 2))
+>String1 : Symbol(String1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 24, 2))
+>Symbol1 : Symbol(Symbol1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 29, 1))
+>Undefined1 : Symbol(Undefined1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 34, 1))
+>Function1 : Symbol(Function1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 39, 1))
+>Obejct1 : Symbol(Obejct1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 44, 1))
+
+function f1_1(u: Union1) {
+>f1_1 : Symbol(f1_1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 54, 98))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 56, 14))
+>Union1 : Symbol(Union1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 51, 1))
+
+    switch (typeof u.key) {
+>u.key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 11, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 56, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 11, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19))
+
+        case 'boolean':
+            u;    // Boolean1 | Boolean2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 56, 14))
+
+            break;
+        case 'number':
+            u;    // Number1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 56, 14))
+
+            break;
+        default:
+            u;    // never
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 56, 14))
+
+            break;
+    }
+}
+
+function f1_2(u: Union1) {
+>f1_2 : Symbol(f1_2, Decl(typeGuardAccordingToPropertyBySwitch.ts, 68, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 70, 14))
+>Union1 : Symbol(Union1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 51, 1))
+
+    switch (typeof u.key) {
+>u.key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 11, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 70, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 11, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19))
+
+        case 'boolean':
+            u;    // Boolean1 | Boolean2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 70, 14))
+
+            break;
+        default:
+            u;    // Number1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 70, 14))
+
+            break;
+    }
+}
+
+
+function f1ElementAccess_1(u: Union1) {
+>f1ElementAccess_1 : Symbol(f1ElementAccess_1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 79, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 82, 27))
+>Union1 : Symbol(Union1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 51, 1))
+
+    if (typeof u["key"] !== 'boolean') {
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 82, 27))
+>"key" : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 11, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19))
+
+        u;      // Number1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 82, 27))
+
+        u.n1;   // number
+>u.n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 22, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 82, 27))
+>n1 : Symbol(Number1.n1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 22, 16))
+    }
+}
+
+// boolean bigint number string symbol undefined function object
+function f2_1(u: Union2) {
+>f2_1 : Symbol(f2_1, Decl(typeGuardAccordingToPropertyBySwitch.ts, 87, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 90, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyBySwitch.ts, 53, 44))
+
+    switch (typeof u.key) {
+>u.key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 16, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 26, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 90, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 16, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 26, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 31, 19) ... and 3 more)
+
+        case 'bigint':
+            u;  // Bigint1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 90, 14))
+
+            break;
+        case 'boolean':
+            u;  // Boolean1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 90, 14))
+
+            break;
+        case 'number':
+            u;  // Number1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 90, 14))
+
+            break;
+        case 'string':
+            u;  // String1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 90, 14))
+
+            break;
+        case 'symbol':
+            u;  // Symbol1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 90, 14))
+
+            break;
+        case 'undefined':
+            u;  // Undefined1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 90, 14))
+
+            break;
+        case 'function':
+            u;  // Function1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 90, 14))
+
+            break;
+        case 'object':
+            u;  // Object1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 90, 14))
+
+            break;
+    }
+}
+
+function f2_2(u: Union2) {
+>f2_2 : Symbol(f2_2, Decl(typeGuardAccordingToPropertyBySwitch.ts, 117, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 119, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyBySwitch.ts, 53, 44))
+
+    switch (typeof u.key) {
+>u.key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 16, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 26, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 119, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 16, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 26, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 31, 19) ... and 3 more)
+
+        case 'bigint':
+        case 'boolean':
+        case 'number':
+        case 'string':
+            u;  // Boolean1 | Number1 | BigInt1 | String1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 119, 14))
+
+            break;
+        case 'symbol':
+        case 'undefined':
+        case 'function':
+        case 'object':
+            u;   // Symbol1 | Undefined1 | Function1 | Obejct1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 119, 14))
+
+            break;
+    }
+}
+
+function f2_3(u: Union2) {
+>f2_3 : Symbol(f2_3, Decl(typeGuardAccordingToPropertyBySwitch.ts, 134, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 136, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyBySwitch.ts, 53, 44))
+
+    switch (typeof u.key) {
+>u.key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 16, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 26, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 136, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 16, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 26, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 31, 19) ... and 3 more)
+
+        case 'bigint':
+        case 'boolean':
+        case 'number':
+        case 'string':
+            u;  // Boolean1 | Number1 | BigInt1 | String1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 136, 14))
+
+            break;
+        default:
+            u;  // Symbol1 | Undefined1 | Function1 | Obejct1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 136, 14))
+
+            break;
+    }
+}
+
+function f2_4(u: Union2) {
+>f2_4 : Symbol(f2_4, Decl(typeGuardAccordingToPropertyBySwitch.ts, 148, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 150, 14))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyBySwitch.ts, 53, 44))
+
+    switch (typeof u.key) {
+>u.key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 16, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 26, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 31, 19) ... and 3 more)
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 150, 14))
+>key : Symbol(key, Decl(typeGuardAccordingToPropertyBySwitch.ts, 6, 20), Decl(typeGuardAccordingToPropertyBySwitch.ts, 16, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 21, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 26, 19), Decl(typeGuardAccordingToPropertyBySwitch.ts, 31, 19) ... and 3 more)
+
+        case 'symbol':
+        case 'undefined':
+        case 'function':
+        case 'object':
+            u;  // Symbol1 | Undefined1 | Function1 | Obejct1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 150, 14))
+
+            break;
+        default:
+            u;  // Boolean1 | BigInt1 | Number1 | String1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyBySwitch.ts, 150, 14))
+
+            break;
+    }
+}
+
+interface A { x: string, y: string };
+>A : Symbol(A, Decl(typeGuardAccordingToPropertyBySwitch.ts, 162, 1))
+>x : Symbol(A.x, Decl(typeGuardAccordingToPropertyBySwitch.ts, 164, 13))
+>y : Symbol(A.y, Decl(typeGuardAccordingToPropertyBySwitch.ts, 164, 24))
+
+interface B { x: number, y: number };
+>B : Symbol(B, Decl(typeGuardAccordingToPropertyBySwitch.ts, 164, 37))
+>x : Symbol(B.x, Decl(typeGuardAccordingToPropertyBySwitch.ts, 165, 13))
+>y : Symbol(B.y, Decl(typeGuardAccordingToPropertyBySwitch.ts, 165, 24))
+
+type X = A | B;
+>X : Symbol(X, Decl(typeGuardAccordingToPropertyBySwitch.ts, 165, 37))
+>A : Symbol(A, Decl(typeGuardAccordingToPropertyBySwitch.ts, 162, 1))
+>B : Symbol(B, Decl(typeGuardAccordingToPropertyBySwitch.ts, 164, 37))
+
+function f3(bar: X) {
+>f3 : Symbol(f3, Decl(typeGuardAccordingToPropertyBySwitch.ts, 166, 15))
+>bar : Symbol(bar, Decl(typeGuardAccordingToPropertyBySwitch.ts, 168, 12))
+>X : Symbol(X, Decl(typeGuardAccordingToPropertyBySwitch.ts, 165, 37))
+
+    switch (typeof bar.x) {
+>bar.x : Symbol(x, Decl(typeGuardAccordingToPropertyBySwitch.ts, 164, 13), Decl(typeGuardAccordingToPropertyBySwitch.ts, 165, 13))
+>bar : Symbol(bar, Decl(typeGuardAccordingToPropertyBySwitch.ts, 168, 12))
+>x : Symbol(x, Decl(typeGuardAccordingToPropertyBySwitch.ts, 164, 13), Decl(typeGuardAccordingToPropertyBySwitch.ts, 165, 13))
+
+        case 'string':
+            let y = bar.y; // string
+>y : Symbol(y, Decl(typeGuardAccordingToPropertyBySwitch.ts, 171, 15))
+>bar.y : Symbol(A.y, Decl(typeGuardAccordingToPropertyBySwitch.ts, 164, 24))
+>bar : Symbol(bar, Decl(typeGuardAccordingToPropertyBySwitch.ts, 168, 12))
+>y : Symbol(A.y, Decl(typeGuardAccordingToPropertyBySwitch.ts, 164, 24))
+
+            break;
+        default:
+            bar.y;
+>bar.y : Symbol(B.y, Decl(typeGuardAccordingToPropertyBySwitch.ts, 165, 24))
+>bar : Symbol(bar, Decl(typeGuardAccordingToPropertyBySwitch.ts, 168, 12))
+>y : Symbol(B.y, Decl(typeGuardAccordingToPropertyBySwitch.ts, 165, 24))
+
+            break;
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyBySwitch.types b/tests/baselines/reference/typeGuardAccordingToPropertyBySwitch.types
new file mode 100644
index 0000000000000..8080cc15b0d89
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyBySwitch.types
@@ -0,0 +1,397 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyBySwitch.ts ===
+// Primitive value ---- boolean bigint number string symbol undefined function object
+// ts special type ---- any, void, unknown, union, intersection
+
+//// Property Access ---- a.b
+//// Element Access ---- a["b"]
+
+interface Boolean1 {
+    key: boolean;
+>key : boolean
+
+    b1: number;
+>b1 : number
+
+};
+
+interface Boolean2 {
+    key: boolean;
+>key : boolean
+
+    b2: number;
+>b2 : number
+
+};
+
+interface BigInt1 {
+    key: bigint;
+>key : bigint
+
+    bi1: number;
+>bi1 : number
+
+};
+
+interface Number1 {
+    key: number;
+>key : number
+
+    n1: number;
+>n1 : number
+
+};
+
+interface String1 {
+    key: string;
+>key : string
+
+    st1: number;
+>st1 : number
+}
+
+interface Symbol1 {
+    key: symbol;
+>key : symbol
+
+    sy1: number;
+>sy1 : number
+}
+
+interface Undefined1 {
+    key: undefined;
+>key : undefined
+
+    u1: number;
+>u1 : number
+}
+
+interface Function1 {
+    key: () => void;
+>key : () => void
+
+    f1: number;
+>f1 : number
+}
+
+interface Obejct1 {
+    key: {
+>key : { notEmpty: number; }
+
+        notEmpty: number;
+>notEmpty : number
+
+    };
+    o1: number;
+>o1 : number
+}
+
+type Union1 = Boolean1 | Boolean2 | Number1;
+>Union1 : Union1
+
+type Union2 = Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1;
+>Union2 : Union2
+
+function f1_1(u: Union1) {
+>f1_1 : (u: Union1) => void
+>u : Union1
+
+    switch (typeof u.key) {
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : number | boolean
+>u : Union1
+>key : number | boolean
+
+        case 'boolean':
+>'boolean' : "boolean"
+
+            u;    // Boolean1 | Boolean2
+>u : Boolean1 | Boolean2
+
+            break;
+        case 'number':
+>'number' : "number"
+
+            u;    // Number1
+>u : Number1
+
+            break;
+        default:
+            u;    // never
+>u : never
+
+            break;
+    }
+}
+
+function f1_2(u: Union1) {
+>f1_2 : (u: Union1) => void
+>u : Union1
+
+    switch (typeof u.key) {
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : number | boolean
+>u : Union1
+>key : number | boolean
+
+        case 'boolean':
+>'boolean' : "boolean"
+
+            u;    // Boolean1 | Boolean2
+>u : Boolean1 | Boolean2
+
+            break;
+        default:
+            u;    // Number1
+>u : Number1
+
+            break;
+    }
+}
+
+
+function f1ElementAccess_1(u: Union1) {
+>f1ElementAccess_1 : (u: Union1) => void
+>u : Union1
+
+    if (typeof u["key"] !== 'boolean') {
+>typeof u["key"] !== 'boolean' : boolean
+>typeof u["key"] : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u["key"] : number | boolean
+>u : Union1
+>"key" : "key"
+>'boolean' : "boolean"
+
+        u;      // Number1
+>u : Number1
+
+        u.n1;   // number
+>u.n1 : number
+>u : Number1
+>n1 : number
+    }
+}
+
+// boolean bigint number string symbol undefined function object
+function f2_1(u: Union2) {
+>f2_1 : (u: Union2) => void
+>u : Union2
+
+    switch (typeof u.key) {
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+
+        case 'bigint':
+>'bigint' : "bigint"
+
+            u;  // Bigint1
+>u : BigInt1
+
+            break;
+        case 'boolean':
+>'boolean' : "boolean"
+
+            u;  // Boolean1
+>u : Boolean1
+
+            break;
+        case 'number':
+>'number' : "number"
+
+            u;  // Number1
+>u : Number1
+
+            break;
+        case 'string':
+>'string' : "string"
+
+            u;  // String1
+>u : String1
+
+            break;
+        case 'symbol':
+>'symbol' : "symbol"
+
+            u;  // Symbol1
+>u : Symbol1
+
+            break;
+        case 'undefined':
+>'undefined' : "undefined"
+
+            u;  // Undefined1
+>u : Undefined1
+
+            break;
+        case 'function':
+>'function' : "function"
+
+            u;  // Function1
+>u : Function1
+
+            break;
+        case 'object':
+>'object' : "object"
+
+            u;  // Object1
+>u : Obejct1
+
+            break;
+    }
+}
+
+function f2_2(u: Union2) {
+>f2_2 : (u: Union2) => void
+>u : Union2
+
+    switch (typeof u.key) {
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+
+        case 'bigint':
+>'bigint' : "bigint"
+
+        case 'boolean':
+>'boolean' : "boolean"
+
+        case 'number':
+>'number' : "number"
+
+        case 'string':
+>'string' : "string"
+
+            u;  // Boolean1 | Number1 | BigInt1 | String1
+>u : Boolean1 | BigInt1 | Number1 | String1
+
+            break;
+        case 'symbol':
+>'symbol' : "symbol"
+
+        case 'undefined':
+>'undefined' : "undefined"
+
+        case 'function':
+>'function' : "function"
+
+        case 'object':
+>'object' : "object"
+
+            u;   // Symbol1 | Undefined1 | Function1 | Obejct1
+>u : Symbol1 | Undefined1 | Function1 | Obejct1
+
+            break;
+    }
+}
+
+function f2_3(u: Union2) {
+>f2_3 : (u: Union2) => void
+>u : Union2
+
+    switch (typeof u.key) {
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+
+        case 'bigint':
+>'bigint' : "bigint"
+
+        case 'boolean':
+>'boolean' : "boolean"
+
+        case 'number':
+>'number' : "number"
+
+        case 'string':
+>'string' : "string"
+
+            u;  // Boolean1 | Number1 | BigInt1 | String1
+>u : Boolean1 | BigInt1 | Number1 | String1
+
+            break;
+        default:
+            u;  // Symbol1 | Undefined1 | Function1 | Obejct1
+>u : Symbol1 | Undefined1 | Function1 | Obejct1
+
+            break;
+    }
+}
+
+function f2_4(u: Union2) {
+>f2_4 : (u: Union2) => void
+>u : Union2
+
+    switch (typeof u.key) {
+>typeof u.key : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+>u : Union2
+>key : string | number | bigint | boolean | symbol | (() => void) | { notEmpty: number; } | undefined
+
+        case 'symbol':
+>'symbol' : "symbol"
+
+        case 'undefined':
+>'undefined' : "undefined"
+
+        case 'function':
+>'function' : "function"
+
+        case 'object':
+>'object' : "object"
+
+            u;  // Symbol1 | Undefined1 | Function1 | Obejct1
+>u : Symbol1 | Undefined1 | Function1 | Obejct1
+
+            break;
+        default:
+            u;  // Boolean1 | BigInt1 | Number1 | String1
+>u : Boolean1 | BigInt1 | Number1 | String1
+
+            break;
+    }
+}
+
+interface A { x: string, y: string };
+>x : string
+>y : string
+
+interface B { x: number, y: number };
+>x : number
+>y : number
+
+type X = A | B;
+>X : X
+
+function f3(bar: X) {
+>f3 : (bar: X) => void
+>bar : X
+
+    switch (typeof bar.x) {
+>typeof bar.x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>bar.x : string | number
+>bar : X
+>x : string | number
+
+        case 'string':
+>'string' : "string"
+
+            let y = bar.y; // string
+>y : string
+>bar.y : string
+>bar : A
+>y : string
+
+            break;
+        default:
+            bar.y;
+>bar.y : number
+>bar : B
+>y : number
+
+            break;
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyDeep.js b/tests/baselines/reference/typeGuardAccordingToPropertyDeep.js
new file mode 100644
index 0000000000000..9d87bbf99a053
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyDeep.js
@@ -0,0 +1,83 @@
+//// [typeGuardAccordingToPropertyDeep.ts]
+//// deep property access ---- a.b.c.d.e.f, a["b"]["c"]["d"]
+//// mix deep property access ---- a.b["c"]["d"].e
+
+interface Foo1 {
+    firstKey: number,
+    inner: {
+        secondKey: number,
+        f1: number
+    }
+}
+
+interface Foo2 {
+    firstKey: boolean,
+    inner: {
+        secondKey: boolean,
+        f2: number
+    }
+}
+
+interface Foo3 {
+    firstKey: string;
+}
+
+type Union = Foo1 | Foo2 | Foo3;
+
+function f(u: Union) {
+    if (typeof u.firstKey === "number" || typeof u.firstKey === "boolean") {
+        u;  // Foo1 | Foo2
+        if (typeof u.inner.secondKey === "boolean") {
+            u;  // Foo2
+        }
+    }
+}
+
+type Union2 = Foo1 | Foo2;
+
+function f2(u: Union2) {
+    if (typeof u.inner["secondKey"] === "boolean") {
+        u;  // Foo2
+    }
+}
+
+function f3(u: Union2) {
+    if (typeof u["inner"]["secondKey"] === "boolean") {
+        u;  // Foo2
+    }
+}
+
+function f4(u: Union2) {
+    if (typeof u["inner"].secondKey === "boolean") {
+        u;  // Foo2
+    }
+}
+
+
+//// [typeGuardAccordingToPropertyDeep.js]
+"use strict";
+//// deep property access ---- a.b.c.d.e.f, a["b"]["c"]["d"]
+//// mix deep property access ---- a.b["c"]["d"].e
+function f(u) {
+    if (typeof u.firstKey === "number" || typeof u.firstKey === "boolean") {
+        u; // Foo1 | Foo2
+        if (typeof u.inner.secondKey === "boolean") {
+            u; // Foo2
+        }
+    }
+}
+function f2(u) {
+    if (typeof u.inner["secondKey"] === "boolean") {
+        u; // Foo2
+    }
+}
+function f3(u) {
+    if (typeof u["inner"]["secondKey"] === "boolean") {
+        u; // Foo2
+    }
+}
+function f4(u) {
+    if (typeof u["inner"].secondKey === "boolean") {
+        u; // Foo2
+    }
+}
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyDeep.symbols b/tests/baselines/reference/typeGuardAccordingToPropertyDeep.symbols
new file mode 100644
index 0000000000000..bd73ca61965bb
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyDeep.symbols
@@ -0,0 +1,132 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyDeep.ts ===
+//// deep property access ---- a.b.c.d.e.f, a["b"]["c"]["d"]
+//// mix deep property access ---- a.b["c"]["d"].e
+
+interface Foo1 {
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyDeep.ts, 0, 0))
+
+    firstKey: number,
+>firstKey : Symbol(Foo1.firstKey, Decl(typeGuardAccordingToPropertyDeep.ts, 3, 16))
+
+    inner: {
+>inner : Symbol(Foo1.inner, Decl(typeGuardAccordingToPropertyDeep.ts, 4, 21))
+
+        secondKey: number,
+>secondKey : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeep.ts, 5, 12))
+
+        f1: number
+>f1 : Symbol(f1, Decl(typeGuardAccordingToPropertyDeep.ts, 6, 26))
+    }
+}
+
+interface Foo2 {
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyDeep.ts, 9, 1))
+
+    firstKey: boolean,
+>firstKey : Symbol(Foo2.firstKey, Decl(typeGuardAccordingToPropertyDeep.ts, 11, 16))
+
+    inner: {
+>inner : Symbol(Foo2.inner, Decl(typeGuardAccordingToPropertyDeep.ts, 12, 22))
+
+        secondKey: boolean,
+>secondKey : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeep.ts, 13, 12))
+
+        f2: number
+>f2 : Symbol(f2, Decl(typeGuardAccordingToPropertyDeep.ts, 14, 27))
+    }
+}
+
+interface Foo3 {
+>Foo3 : Symbol(Foo3, Decl(typeGuardAccordingToPropertyDeep.ts, 17, 1))
+
+    firstKey: string;
+>firstKey : Symbol(Foo3.firstKey, Decl(typeGuardAccordingToPropertyDeep.ts, 19, 16))
+}
+
+type Union = Foo1 | Foo2 | Foo3;
+>Union : Symbol(Union, Decl(typeGuardAccordingToPropertyDeep.ts, 21, 1))
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyDeep.ts, 0, 0))
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyDeep.ts, 9, 1))
+>Foo3 : Symbol(Foo3, Decl(typeGuardAccordingToPropertyDeep.ts, 17, 1))
+
+function f(u: Union) {
+>f : Symbol(f, Decl(typeGuardAccordingToPropertyDeep.ts, 23, 32))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 25, 11))
+>Union : Symbol(Union, Decl(typeGuardAccordingToPropertyDeep.ts, 21, 1))
+
+    if (typeof u.firstKey === "number" || typeof u.firstKey === "boolean") {
+>u.firstKey : Symbol(firstKey, Decl(typeGuardAccordingToPropertyDeep.ts, 3, 16), Decl(typeGuardAccordingToPropertyDeep.ts, 11, 16), Decl(typeGuardAccordingToPropertyDeep.ts, 19, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 25, 11))
+>firstKey : Symbol(firstKey, Decl(typeGuardAccordingToPropertyDeep.ts, 3, 16), Decl(typeGuardAccordingToPropertyDeep.ts, 11, 16), Decl(typeGuardAccordingToPropertyDeep.ts, 19, 16))
+>u.firstKey : Symbol(firstKey, Decl(typeGuardAccordingToPropertyDeep.ts, 11, 16), Decl(typeGuardAccordingToPropertyDeep.ts, 19, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 25, 11))
+>firstKey : Symbol(firstKey, Decl(typeGuardAccordingToPropertyDeep.ts, 11, 16), Decl(typeGuardAccordingToPropertyDeep.ts, 19, 16))
+
+        u;  // Foo1 | Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 25, 11))
+
+        if (typeof u.inner.secondKey === "boolean") {
+>u.inner.secondKey : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeep.ts, 5, 12), Decl(typeGuardAccordingToPropertyDeep.ts, 13, 12))
+>u.inner : Symbol(inner, Decl(typeGuardAccordingToPropertyDeep.ts, 4, 21), Decl(typeGuardAccordingToPropertyDeep.ts, 12, 22))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 25, 11))
+>inner : Symbol(inner, Decl(typeGuardAccordingToPropertyDeep.ts, 4, 21), Decl(typeGuardAccordingToPropertyDeep.ts, 12, 22))
+>secondKey : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeep.ts, 5, 12), Decl(typeGuardAccordingToPropertyDeep.ts, 13, 12))
+
+            u;  // Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 25, 11))
+        }
+    }
+}
+
+type Union2 = Foo1 | Foo2;
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyDeep.ts, 32, 1))
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyDeep.ts, 0, 0))
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyDeep.ts, 9, 1))
+
+function f2(u: Union2) {
+>f2 : Symbol(f2, Decl(typeGuardAccordingToPropertyDeep.ts, 34, 26))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 36, 12))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyDeep.ts, 32, 1))
+
+    if (typeof u.inner["secondKey"] === "boolean") {
+>u.inner : Symbol(inner, Decl(typeGuardAccordingToPropertyDeep.ts, 4, 21), Decl(typeGuardAccordingToPropertyDeep.ts, 12, 22))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 36, 12))
+>inner : Symbol(inner, Decl(typeGuardAccordingToPropertyDeep.ts, 4, 21), Decl(typeGuardAccordingToPropertyDeep.ts, 12, 22))
+>"secondKey" : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeep.ts, 5, 12), Decl(typeGuardAccordingToPropertyDeep.ts, 13, 12))
+
+        u;  // Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 36, 12))
+    }
+}
+
+function f3(u: Union2) {
+>f3 : Symbol(f3, Decl(typeGuardAccordingToPropertyDeep.ts, 40, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 42, 12))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyDeep.ts, 32, 1))
+
+    if (typeof u["inner"]["secondKey"] === "boolean") {
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 42, 12))
+>"inner" : Symbol(inner, Decl(typeGuardAccordingToPropertyDeep.ts, 4, 21), Decl(typeGuardAccordingToPropertyDeep.ts, 12, 22))
+>"secondKey" : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeep.ts, 5, 12), Decl(typeGuardAccordingToPropertyDeep.ts, 13, 12))
+
+        u;  // Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 42, 12))
+    }
+}
+
+function f4(u: Union2) {
+>f4 : Symbol(f4, Decl(typeGuardAccordingToPropertyDeep.ts, 46, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 48, 12))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyDeep.ts, 32, 1))
+
+    if (typeof u["inner"].secondKey === "boolean") {
+>u["inner"].secondKey : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeep.ts, 5, 12), Decl(typeGuardAccordingToPropertyDeep.ts, 13, 12))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 48, 12))
+>"inner" : Symbol(inner, Decl(typeGuardAccordingToPropertyDeep.ts, 4, 21), Decl(typeGuardAccordingToPropertyDeep.ts, 12, 22))
+>secondKey : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeep.ts, 5, 12), Decl(typeGuardAccordingToPropertyDeep.ts, 13, 12))
+
+        u;  // Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeep.ts, 48, 12))
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyDeep.types b/tests/baselines/reference/typeGuardAccordingToPropertyDeep.types
new file mode 100644
index 0000000000000..264d2576d44f4
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyDeep.types
@@ -0,0 +1,140 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyDeep.ts ===
+//// deep property access ---- a.b.c.d.e.f, a["b"]["c"]["d"]
+//// mix deep property access ---- a.b["c"]["d"].e
+
+interface Foo1 {
+    firstKey: number,
+>firstKey : number
+
+    inner: {
+>inner : { secondKey: number; f1: number; }
+
+        secondKey: number,
+>secondKey : number
+
+        f1: number
+>f1 : number
+    }
+}
+
+interface Foo2 {
+    firstKey: boolean,
+>firstKey : boolean
+
+    inner: {
+>inner : { secondKey: boolean; f2: number; }
+
+        secondKey: boolean,
+>secondKey : boolean
+
+        f2: number
+>f2 : number
+    }
+}
+
+interface Foo3 {
+    firstKey: string;
+>firstKey : string
+}
+
+type Union = Foo1 | Foo2 | Foo3;
+>Union : Union
+
+function f(u: Union) {
+>f : (u: Union) => void
+>u : Union
+
+    if (typeof u.firstKey === "number" || typeof u.firstKey === "boolean") {
+>typeof u.firstKey === "number" || typeof u.firstKey === "boolean" : boolean
+>typeof u.firstKey === "number" : boolean
+>typeof u.firstKey : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.firstKey : string | number | boolean
+>u : Union
+>firstKey : string | number | boolean
+>"number" : "number"
+>typeof u.firstKey === "boolean" : boolean
+>typeof u.firstKey : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.firstKey : string | boolean
+>u : Foo2 | Foo3
+>firstKey : string | boolean
+>"boolean" : "boolean"
+
+        u;  // Foo1 | Foo2
+>u : Foo1 | Foo2
+
+        if (typeof u.inner.secondKey === "boolean") {
+>typeof u.inner.secondKey === "boolean" : boolean
+>typeof u.inner.secondKey : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.inner.secondKey : number | boolean
+>u.inner : { secondKey: number; f1: number; } | { secondKey: boolean; f2: number; }
+>u : Foo1 | Foo2
+>inner : { secondKey: number; f1: number; } | { secondKey: boolean; f2: number; }
+>secondKey : number | boolean
+>"boolean" : "boolean"
+
+            u;  // Foo2
+>u : Foo2
+        }
+    }
+}
+
+type Union2 = Foo1 | Foo2;
+>Union2 : Union2
+
+function f2(u: Union2) {
+>f2 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u.inner["secondKey"] === "boolean") {
+>typeof u.inner["secondKey"] === "boolean" : boolean
+>typeof u.inner["secondKey"] : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.inner["secondKey"] : number | boolean
+>u.inner : { secondKey: number; f1: number; } | { secondKey: boolean; f2: number; }
+>u : Union2
+>inner : { secondKey: number; f1: number; } | { secondKey: boolean; f2: number; }
+>"secondKey" : "secondKey"
+>"boolean" : "boolean"
+
+        u;  // Foo2
+>u : Foo2
+    }
+}
+
+function f3(u: Union2) {
+>f3 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u["inner"]["secondKey"] === "boolean") {
+>typeof u["inner"]["secondKey"] === "boolean" : boolean
+>typeof u["inner"]["secondKey"] : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u["inner"]["secondKey"] : number | boolean
+>u["inner"] : { secondKey: number; f1: number; } | { secondKey: boolean; f2: number; }
+>u : Union2
+>"inner" : "inner"
+>"secondKey" : "secondKey"
+>"boolean" : "boolean"
+
+        u;  // Foo2
+>u : Foo2
+    }
+}
+
+function f4(u: Union2) {
+>f4 : (u: Union2) => void
+>u : Union2
+
+    if (typeof u["inner"].secondKey === "boolean") {
+>typeof u["inner"].secondKey === "boolean" : boolean
+>typeof u["inner"].secondKey : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u["inner"].secondKey : number | boolean
+>u["inner"] : { secondKey: number; f1: number; } | { secondKey: boolean; f2: number; }
+>u : Union2
+>"inner" : "inner"
+>secondKey : number | boolean
+>"boolean" : "boolean"
+
+        u;  // Foo2
+>u : Foo2
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyDeepBySwitch.js b/tests/baselines/reference/typeGuardAccordingToPropertyDeepBySwitch.js
new file mode 100644
index 0000000000000..e8c73e827211e
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyDeepBySwitch.js
@@ -0,0 +1,74 @@
+//// [typeGuardAccordingToPropertyDeepBySwitch.ts]
+interface Foo1 {
+    firstKey: number,
+    inner: {
+        secondKey: number,
+        f1: number
+    }
+}
+
+interface Foo2 {
+    firstKey: boolean,
+    inner: {
+        secondKey: boolean,
+        f2: number
+    }
+}
+
+interface Foo3 {
+    firstKey: string;
+}
+
+type Union = Foo1 | Foo2 | Foo3;
+
+function f(u: Union) {
+    switch (typeof u.firstKey) {
+        case 'number':
+        case 'boolean':
+            u;
+            switch (typeof u.inner.secondKey) {
+                case 'boolean':
+                    u;
+            }
+    }
+}
+
+type Union2 = Foo1 | Foo2;
+
+// fall through
+function f2(u: Union2) {
+    switch (typeof u.inner["secondKey"]) {
+        case 'boolean':
+            u;  // never
+        case 'bigint':
+            u;  // Foo2
+        default:
+            u;  // Union2
+    }
+}
+
+
+//// [typeGuardAccordingToPropertyDeepBySwitch.js]
+"use strict";
+function f(u) {
+    switch (typeof u.firstKey) {
+        case 'number':
+        case 'boolean':
+            u;
+            switch (typeof u.inner.secondKey) {
+                case 'boolean':
+                    u;
+            }
+    }
+}
+// fall through
+function f2(u) {
+    switch (typeof u.inner["secondKey"]) {
+        case 'boolean':
+            u; // never
+        case 'bigint':
+            u; // Foo2
+        default:
+            u; // Union2
+    }
+}
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyDeepBySwitch.symbols b/tests/baselines/reference/typeGuardAccordingToPropertyDeepBySwitch.symbols
new file mode 100644
index 0000000000000..7e6b07084869a
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyDeepBySwitch.symbols
@@ -0,0 +1,108 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyDeepBySwitch.ts ===
+interface Foo1 {
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 0, 0))
+
+    firstKey: number,
+>firstKey : Symbol(Foo1.firstKey, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 0, 16))
+
+    inner: {
+>inner : Symbol(Foo1.inner, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 1, 21))
+
+        secondKey: number,
+>secondKey : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 2, 12))
+
+        f1: number
+>f1 : Symbol(f1, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 3, 26))
+    }
+}
+
+interface Foo2 {
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 6, 1))
+
+    firstKey: boolean,
+>firstKey : Symbol(Foo2.firstKey, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 8, 16))
+
+    inner: {
+>inner : Symbol(Foo2.inner, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 9, 22))
+
+        secondKey: boolean,
+>secondKey : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 10, 12))
+
+        f2: number
+>f2 : Symbol(f2, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 11, 27))
+    }
+}
+
+interface Foo3 {
+>Foo3 : Symbol(Foo3, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 14, 1))
+
+    firstKey: string;
+>firstKey : Symbol(Foo3.firstKey, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 16, 16))
+}
+
+type Union = Foo1 | Foo2 | Foo3;
+>Union : Symbol(Union, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 18, 1))
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 0, 0))
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 6, 1))
+>Foo3 : Symbol(Foo3, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 14, 1))
+
+function f(u: Union) {
+>f : Symbol(f, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 20, 32))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 22, 11))
+>Union : Symbol(Union, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 18, 1))
+
+    switch (typeof u.firstKey) {
+>u.firstKey : Symbol(firstKey, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 8, 16), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 16, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 22, 11))
+>firstKey : Symbol(firstKey, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 8, 16), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 16, 16))
+
+        case 'number':
+        case 'boolean':
+            u;
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 22, 11))
+
+            switch (typeof u.inner.secondKey) {
+>u.inner.secondKey : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 2, 12), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 10, 12))
+>u.inner : Symbol(inner, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 1, 21), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 9, 22))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 22, 11))
+>inner : Symbol(inner, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 1, 21), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 9, 22))
+>secondKey : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 2, 12), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 10, 12))
+
+                case 'boolean':
+                    u;
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 22, 11))
+            }
+    }
+}
+
+type Union2 = Foo1 | Foo2;
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 32, 1))
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 0, 0))
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 6, 1))
+
+// fall through
+function f2(u: Union2) {
+>f2 : Symbol(f2, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 34, 26))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 37, 12))
+>Union2 : Symbol(Union2, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 32, 1))
+
+    switch (typeof u.inner["secondKey"]) {
+>u.inner : Symbol(inner, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 1, 21), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 9, 22))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 37, 12))
+>inner : Symbol(inner, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 1, 21), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 9, 22))
+>"secondKey" : Symbol(secondKey, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 2, 12), Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 10, 12))
+
+        case 'boolean':
+            u;  // never
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 37, 12))
+
+        case 'bigint':
+            u;  // Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 37, 12))
+
+        default:
+            u;  // Union2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyDeepBySwitch.ts, 37, 12))
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyDeepBySwitch.types b/tests/baselines/reference/typeGuardAccordingToPropertyDeepBySwitch.types
new file mode 100644
index 0000000000000..ac3361da3adf0
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyDeepBySwitch.types
@@ -0,0 +1,109 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyDeepBySwitch.ts ===
+interface Foo1 {
+    firstKey: number,
+>firstKey : number
+
+    inner: {
+>inner : { secondKey: number; f1: number; }
+
+        secondKey: number,
+>secondKey : number
+
+        f1: number
+>f1 : number
+    }
+}
+
+interface Foo2 {
+    firstKey: boolean,
+>firstKey : boolean
+
+    inner: {
+>inner : { secondKey: boolean; f2: number; }
+
+        secondKey: boolean,
+>secondKey : boolean
+
+        f2: number
+>f2 : number
+    }
+}
+
+interface Foo3 {
+    firstKey: string;
+>firstKey : string
+}
+
+type Union = Foo1 | Foo2 | Foo3;
+>Union : Union
+
+function f(u: Union) {
+>f : (u: Union) => void
+>u : Union
+
+    switch (typeof u.firstKey) {
+>typeof u.firstKey : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.firstKey : string | number | boolean
+>u : Union
+>firstKey : string | number | boolean
+
+        case 'number':
+>'number' : "number"
+
+        case 'boolean':
+>'boolean' : "boolean"
+
+            u;
+>u : Foo1 | Foo2
+
+            switch (typeof u.inner.secondKey) {
+>typeof u.inner.secondKey : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.inner.secondKey : number | boolean
+>u.inner : { secondKey: number; f1: number; } | { secondKey: boolean; f2: number; }
+>u : Foo1 | Foo2
+>inner : { secondKey: number; f1: number; } | { secondKey: boolean; f2: number; }
+>secondKey : number | boolean
+
+                case 'boolean':
+>'boolean' : "boolean"
+
+                    u;
+>u : Foo2
+            }
+    }
+}
+
+type Union2 = Foo1 | Foo2;
+>Union2 : Union2
+
+// fall through
+function f2(u: Union2) {
+>f2 : (u: Union2) => void
+>u : Union2
+
+    switch (typeof u.inner["secondKey"]) {
+>typeof u.inner["secondKey"] : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.inner["secondKey"] : number | boolean
+>u.inner : { secondKey: number; f1: number; } | { secondKey: boolean; f2: number; }
+>u : Union2
+>inner : { secondKey: number; f1: number; } | { secondKey: boolean; f2: number; }
+>"secondKey" : "secondKey"
+
+        case 'boolean':
+>'boolean' : "boolean"
+
+            u;  // never
+>u : Foo2
+
+        case 'bigint':
+>'bigint' : "bigint"
+
+            u;  // Foo2
+>u : Foo2
+
+        default:
+            u;  // Union2
+>u : Union2
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyOptional.errors.txt b/tests/baselines/reference/typeGuardAccordingToPropertyOptional.errors.txt
new file mode 100644
index 0000000000000..8cbdfaf3779a6
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyOptional.errors.txt
@@ -0,0 +1,112 @@
+tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptional.ts(58,63): error TS2339: Property 'key2' does not exist on type 'never'.
+
+
+==== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptional.ts (1 errors) ====
+    interface Foo1 {
+        key1: {
+            key2: number;
+        } | undefined;
+        f1: number;
+    }
+    
+    interface Foo2 {
+        key1: {
+            key2: string
+        } | undefined;
+        f2: number;
+    }
+    
+    interface Foo3 {
+        key1: {
+            key2: number;
+        };
+        f2: number;
+    }
+    type U1 = Foo1 | Foo2 | Foo3;
+    type U2 = Foo1 | Foo2 | Foo3 | undefined;
+    
+    
+    // unnecessary optional chain
+    function f1(u: U1) {
+        if (typeof u?.key1 !== 'number') {
+            u;  // U1
+        }
+        if (typeof u?.key1 === 'number') {
+            u;  // never
+        }
+        if (typeof u?.key1 !== 'undefined') {
+            u;  // U1
+        }
+        if (typeof u?.key1 === 'undefined') {
+            u;  // Foo1 | Foo2
+        }
+    }
+    
+    // non-root optional chain
+    function f2(u: U1) {
+        if (typeof u.key1?.key2 !== 'number') {
+            u;  //Foo1 | Foo2
+        }
+        if (typeof u.key1?.key2 === 'number') {
+            u;  //Foo1 | Foo3
+        }
+        if (typeof u.key1?.key2 !== 'undefined') {
+            u;  //U1
+        }
+        if (typeof u.key1?.key2 === 'undefined') {
+            u;  //Foo1 | Foo2
+        }
+    }
+    
+    function f2Plus(u: U1) {
+        if (typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number') {
+                                                                  ~~~~
+!!! error TS2339: Property 'key2' does not exist on type 'never'.
+            u;    //should be never, but this should be a design limit?
+        }
+        if (typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number') {
+            u;    //U1
+        }
+        if (typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined') {
+            u;    //should be never, but this should be a design limit?
+        }
+        if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined') {
+            u;    //U1
+        }
+        if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined') {
+            u;    //U1
+        }
+    }
+    
+    // root optional chain
+    function f3(u: U2) {
+        if (typeof u?.key1 !== 'number') {
+            u;  //U2
+        }
+        if (typeof u?.key1 === 'number') {
+            u;  //never
+        }
+        if (typeof u?.key1 !== 'undefined') {
+            u;  //Foo1 | Foo2 | Foo3
+        }
+        if (typeof u?.key1 === 'undefined') {
+            u;  //Foo1 | Foo2 | Undefined
+        }
+    }
+    
+    // multi optional chain
+    function f4(u: U2) {
+        if (typeof u?.key1?.key2 !== 'number') {
+            u;  //Foo1 | Foo2 | Undefined
+        }
+        if (typeof u?.key1?.key2 === 'number') {
+            u;  //Foo1 | Foo3
+        }
+        if (typeof u?.key1?.key2 !== 'undefined') {
+            u;  //Foo1 | Foo2 | Foo3
+        }
+        if (typeof u?.key1?.key2 === 'undefined') {
+            u;  //Foo1 | Foo2 | Undefined
+        }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyOptional.js b/tests/baselines/reference/typeGuardAccordingToPropertyOptional.js
new file mode 100644
index 0000000000000..ee1258450415f
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyOptional.js
@@ -0,0 +1,190 @@
+//// [typeGuardAccordingToPropertyOptional.ts]
+interface Foo1 {
+    key1: {
+        key2: number;
+    } | undefined;
+    f1: number;
+}
+
+interface Foo2 {
+    key1: {
+        key2: string
+    } | undefined;
+    f2: number;
+}
+
+interface Foo3 {
+    key1: {
+        key2: number;
+    };
+    f2: number;
+}
+type U1 = Foo1 | Foo2 | Foo3;
+type U2 = Foo1 | Foo2 | Foo3 | undefined;
+
+
+// unnecessary optional chain
+function f1(u: U1) {
+    if (typeof u?.key1 !== 'number') {
+        u;  // U1
+    }
+    if (typeof u?.key1 === 'number') {
+        u;  // never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+        u;  // U1
+    }
+    if (typeof u?.key1 === 'undefined') {
+        u;  // Foo1 | Foo2
+    }
+}
+
+// non-root optional chain
+function f2(u: U1) {
+    if (typeof u.key1?.key2 !== 'number') {
+        u;  //Foo1 | Foo2
+    }
+    if (typeof u.key1?.key2 === 'number') {
+        u;  //Foo1 | Foo3
+    }
+    if (typeof u.key1?.key2 !== 'undefined') {
+        u;  //U1
+    }
+    if (typeof u.key1?.key2 === 'undefined') {
+        u;  //Foo1 | Foo2
+    }
+}
+
+function f2Plus(u: U1) {
+    if (typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number') {
+        u;    //should be never, but this should be a design limit?
+    }
+    if (typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number') {
+        u;    //U1
+    }
+    if (typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined') {
+        u;    //should be never, but this should be a design limit?
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined') {
+        u;    //U1
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined') {
+        u;    //U1
+    }
+}
+
+// root optional chain
+function f3(u: U2) {
+    if (typeof u?.key1 !== 'number') {
+        u;  //U2
+    }
+    if (typeof u?.key1 === 'number') {
+        u;  //never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+        u;  //Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1 === 'undefined') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+}
+
+// multi optional chain
+function f4(u: U2) {
+    if (typeof u?.key1?.key2 !== 'number') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+    if (typeof u?.key1?.key2 === 'number') {
+        u;  //Foo1 | Foo3
+    }
+    if (typeof u?.key1?.key2 !== 'undefined') {
+        u;  //Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1?.key2 === 'undefined') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+}
+
+
+//// [typeGuardAccordingToPropertyOptional.js]
+"use strict";
+// unnecessary optional chain
+function f1(u) {
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) !== 'number') {
+        u; // U1
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) === 'number') {
+        u; // never
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) !== 'undefined') {
+        u; // U1
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) === 'undefined') {
+        u; // Foo1 | Foo2
+    }
+}
+// non-root optional chain
+function f2(u) {
+    var _a, _b, _c, _d;
+    if (typeof ((_a = u.key1) === null || _a === void 0 ? void 0 : _a.key2) !== 'number') {
+        u; //Foo1 | Foo2
+    }
+    if (typeof ((_b = u.key1) === null || _b === void 0 ? void 0 : _b.key2) === 'number') {
+        u; //Foo1 | Foo3
+    }
+    if (typeof ((_c = u.key1) === null || _c === void 0 ? void 0 : _c.key2) !== 'undefined') {
+        u; //U1
+    }
+    if (typeof ((_d = u.key1) === null || _d === void 0 ? void 0 : _d.key2) === 'undefined') {
+        u; //Foo1 | Foo2
+    }
+}
+function f2Plus(u) {
+    var _a, _b, _c, _d, _e, _f, _g, _h, _j, _k;
+    if (typeof ((_a = u.key1) === null || _a === void 0 ? void 0 : _a.key2) === 'undefined' && typeof ((_b = u.key1) === null || _b === void 0 ? void 0 : _b.key2) === 'number') {
+        u; //should be never, but this should be a design limit?
+    }
+    if (typeof ((_c = u.key1) === null || _c === void 0 ? void 0 : _c.key2) === 'undefined' || typeof ((_d = u.key1) === null || _d === void 0 ? void 0 : _d.key2) === 'number') {
+        u; //U1
+    }
+    if (typeof ((_e = u.key1) === null || _e === void 0 ? void 0 : _e.key2) === 'number' && typeof ((_f = u.key1) === null || _f === void 0 ? void 0 : _f.key2) === 'undefined') {
+        u; //should be never, but this should be a design limit?
+    }
+    if (typeof ((_g = u.key1) === null || _g === void 0 ? void 0 : _g.key2) === 'number' || typeof ((_h = u.key1) === null || _h === void 0 ? void 0 : _h.key2) === 'undefined') {
+        u; //U1
+    }
+    if (typeof ((_j = u.key1) === null || _j === void 0 ? void 0 : _j.key2) === 'number' || typeof ((_k = u.key1) === null || _k === void 0 ? void 0 : _k.key2) !== 'undefined') {
+        u; //U1
+    }
+}
+// root optional chain
+function f3(u) {
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) !== 'number') {
+        u; //U2
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) === 'number') {
+        u; //never
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) !== 'undefined') {
+        u; //Foo1 | Foo2 | Foo3
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) === 'undefined') {
+        u; //Foo1 | Foo2 | Undefined
+    }
+}
+// multi optional chain
+function f4(u) {
+    var _a, _b, _c, _d;
+    if (typeof ((_a = u === null || u === void 0 ? void 0 : u.key1) === null || _a === void 0 ? void 0 : _a.key2) !== 'number') {
+        u; //Foo1 | Foo2 | Undefined
+    }
+    if (typeof ((_b = u === null || u === void 0 ? void 0 : u.key1) === null || _b === void 0 ? void 0 : _b.key2) === 'number') {
+        u; //Foo1 | Foo3
+    }
+    if (typeof ((_c = u === null || u === void 0 ? void 0 : u.key1) === null || _c === void 0 ? void 0 : _c.key2) !== 'undefined') {
+        u; //Foo1 | Foo2 | Foo3
+    }
+    if (typeof ((_d = u === null || u === void 0 ? void 0 : u.key1) === null || _d === void 0 ? void 0 : _d.key2) === 'undefined') {
+        u; //Foo1 | Foo2 | Undefined
+    }
+}
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyOptional.symbols b/tests/baselines/reference/typeGuardAccordingToPropertyOptional.symbols
new file mode 100644
index 0000000000000..5175c101a0215
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyOptional.symbols
@@ -0,0 +1,311 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptional.ts ===
+interface Foo1 {
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 0))
+
+    key1: {
+>key1 : Symbol(Foo1.key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16))
+
+        key2: number;
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11))
+
+    } | undefined;
+    f1: number;
+>f1 : Symbol(Foo1.f1, Decl(typeGuardAccordingToPropertyOptional.ts, 3, 18))
+}
+
+interface Foo2 {
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyOptional.ts, 5, 1))
+
+    key1: {
+>key1 : Symbol(Foo2.key1, Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16))
+
+        key2: string
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+
+    } | undefined;
+    f2: number;
+>f2 : Symbol(Foo2.f2, Decl(typeGuardAccordingToPropertyOptional.ts, 10, 18))
+}
+
+interface Foo3 {
+>Foo3 : Symbol(Foo3, Decl(typeGuardAccordingToPropertyOptional.ts, 12, 1))
+
+    key1: {
+>key1 : Symbol(Foo3.key1, Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+
+        key2: number;
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+
+    };
+    f2: number;
+>f2 : Symbol(Foo3.f2, Decl(typeGuardAccordingToPropertyOptional.ts, 17, 6))
+}
+type U1 = Foo1 | Foo2 | Foo3;
+>U1 : Symbol(U1, Decl(typeGuardAccordingToPropertyOptional.ts, 19, 1))
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 0))
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyOptional.ts, 5, 1))
+>Foo3 : Symbol(Foo3, Decl(typeGuardAccordingToPropertyOptional.ts, 12, 1))
+
+type U2 = Foo1 | Foo2 | Foo3 | undefined;
+>U2 : Symbol(U2, Decl(typeGuardAccordingToPropertyOptional.ts, 20, 29))
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 0))
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyOptional.ts, 5, 1))
+>Foo3 : Symbol(Foo3, Decl(typeGuardAccordingToPropertyOptional.ts, 12, 1))
+
+
+// unnecessary optional chain
+function f1(u: U1) {
+>f1 : Symbol(f1, Decl(typeGuardAccordingToPropertyOptional.ts, 21, 41))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 25, 12))
+>U1 : Symbol(U1, Decl(typeGuardAccordingToPropertyOptional.ts, 19, 1))
+
+    if (typeof u?.key1 !== 'number') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 25, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+
+        u;  // U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 25, 12))
+    }
+    if (typeof u?.key1 === 'number') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 25, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+
+        u;  // never
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 25, 12))
+    }
+    if (typeof u?.key1 !== 'undefined') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 25, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+
+        u;  // U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 25, 12))
+    }
+    if (typeof u?.key1 === 'undefined') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 25, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+
+        u;  // Foo1 | Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 25, 12))
+    }
+}
+
+// non-root optional chain
+function f2(u: U1) {
+>f2 : Symbol(f2, Decl(typeGuardAccordingToPropertyOptional.ts, 38, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 41, 12))
+>U1 : Symbol(U1, Decl(typeGuardAccordingToPropertyOptional.ts, 19, 1))
+
+    if (typeof u.key1?.key2 !== 'number') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 41, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+
+        u;  //Foo1 | Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 41, 12))
+    }
+    if (typeof u.key1?.key2 === 'number') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 41, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+
+        u;  //Foo1 | Foo3
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 41, 12))
+    }
+    if (typeof u.key1?.key2 !== 'undefined') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 41, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+
+        u;  //U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 41, 12))
+    }
+    if (typeof u.key1?.key2 === 'undefined') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 41, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+
+        u;  //Foo1 | Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 41, 12))
+    }
+}
+
+function f2Plus(u: U1) {
+>f2Plus : Symbol(f2Plus, Decl(typeGuardAccordingToPropertyOptional.ts, 54, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>U1 : Symbol(U1, Decl(typeGuardAccordingToPropertyOptional.ts, 19, 1))
+
+    if (typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16))
+
+        u;    //should be never, but this should be a design limit?
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+    }
+    if (typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+
+        u;    //U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+    }
+    if (typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11))
+
+        u;    //should be never, but this should be a design limit?
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+
+        u;    //U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11))
+
+        u;    //U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 56, 16))
+    }
+}
+
+// root optional chain
+function f3(u: U2) {
+>f3 : Symbol(f3, Decl(typeGuardAccordingToPropertyOptional.ts, 72, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 75, 12))
+>U2 : Symbol(U2, Decl(typeGuardAccordingToPropertyOptional.ts, 20, 29))
+
+    if (typeof u?.key1 !== 'number') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 75, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+
+        u;  //U2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 75, 12))
+    }
+    if (typeof u?.key1 === 'number') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 75, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+
+        u;  //never
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 75, 12))
+    }
+    if (typeof u?.key1 !== 'undefined') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 75, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+
+        u;  //Foo1 | Foo2 | Foo3
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 75, 12))
+    }
+    if (typeof u?.key1 === 'undefined') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 75, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 75, 12))
+    }
+}
+
+// multi optional chain
+function f4(u: U2) {
+>f4 : Symbol(f4, Decl(typeGuardAccordingToPropertyOptional.ts, 88, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 91, 12))
+>U2 : Symbol(U2, Decl(typeGuardAccordingToPropertyOptional.ts, 20, 29))
+
+    if (typeof u?.key1?.key2 !== 'number') {
+>u?.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 91, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 91, 12))
+    }
+    if (typeof u?.key1?.key2 === 'number') {
+>u?.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 91, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+
+        u;  //Foo1 | Foo3
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 91, 12))
+    }
+    if (typeof u?.key1?.key2 !== 'undefined') {
+>u?.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 91, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+
+        u;  //Foo1 | Foo2 | Foo3
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 91, 12))
+    }
+    if (typeof u?.key1?.key2 === 'undefined') {
+>u?.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 91, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptional.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptional.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptional.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptional.ts, 15, 11))
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptional.ts, 91, 12))
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyOptional.types b/tests/baselines/reference/typeGuardAccordingToPropertyOptional.types
new file mode 100644
index 0000000000000..7043fceeb70e4
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyOptional.types
@@ -0,0 +1,379 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptional.ts ===
+interface Foo1 {
+    key1: {
+>key1 : { key2: number; } | undefined
+
+        key2: number;
+>key2 : number
+
+    } | undefined;
+    f1: number;
+>f1 : number
+}
+
+interface Foo2 {
+    key1: {
+>key1 : { key2: string; } | undefined
+
+        key2: string
+>key2 : string
+
+    } | undefined;
+    f2: number;
+>f2 : number
+}
+
+interface Foo3 {
+    key1: {
+>key1 : { key2: number; }
+
+        key2: number;
+>key2 : number
+
+    };
+    f2: number;
+>f2 : number
+}
+type U1 = Foo1 | Foo2 | Foo3;
+>U1 : U1
+
+type U2 = Foo1 | Foo2 | Foo3 | undefined;
+>U2 : U2
+
+
+// unnecessary optional chain
+function f1(u: U1) {
+>f1 : (u: U1) => void
+>u : U1
+
+    if (typeof u?.key1 !== 'number') {
+>typeof u?.key1 !== 'number' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'number' : "number"
+
+        u;  // U1
+>u : U1
+    }
+    if (typeof u?.key1 === 'number') {
+>typeof u?.key1 === 'number' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'number' : "number"
+
+        u;  // never
+>u : never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+>typeof u?.key1 !== 'undefined' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'undefined' : "undefined"
+
+        u;  // U1
+>u : U1
+    }
+    if (typeof u?.key1 === 'undefined') {
+>typeof u?.key1 === 'undefined' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'undefined' : "undefined"
+
+        u;  // Foo1 | Foo2
+>u : Foo1 | Foo2
+    }
+}
+
+// non-root optional chain
+function f2(u: U1) {
+>f2 : (u: U1) => void
+>u : U1
+
+    if (typeof u.key1?.key2 !== 'number') {
+>typeof u.key1?.key2 !== 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+
+        u;  //Foo1 | Foo2
+>u : Foo1 | Foo2
+    }
+    if (typeof u.key1?.key2 === 'number') {
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+
+        u;  //Foo1 | Foo3
+>u : Foo1 | Foo3
+    }
+    if (typeof u.key1?.key2 !== 'undefined') {
+>typeof u.key1?.key2 !== 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+
+        u;  //U1
+>u : U1
+    }
+    if (typeof u.key1?.key2 === 'undefined') {
+>typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+
+        u;  //Foo1 | Foo2
+>u : Foo1 | Foo2
+    }
+}
+
+function f2Plus(u: U1) {
+>f2Plus : (u: U1) => void
+>u : U1
+
+    if (typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number') {
+>typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : any
+>u.key1 : undefined
+>u : Foo1 | Foo2
+>key1 : undefined
+>key2 : any
+>'number' : "number"
+
+        u;    //should be never, but this should be a design limit?
+>u : Foo1
+    }
+    if (typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number') {
+>typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; }
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; }
+>key2 : string | number
+>'number' : "number"
+
+        u;    //U1
+>u : U1
+    }
+    if (typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined') {
+>typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+>typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : number
+>u.key1 : { key2: number; }
+>u : Foo1 | Foo3
+>key1 : { key2: number; }
+>key2 : number
+>'undefined' : "undefined"
+
+        u;    //should be never, but this should be a design limit?
+>u : Foo1
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined') {
+>typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+>typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | undefined
+>u.key1 : { key2: string; } | undefined
+>u : Foo1 | Foo2
+>key1 : { key2: string; } | undefined
+>key2 : string | undefined
+>'undefined' : "undefined"
+
+        u;    //U1
+>u : U1
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined') {
+>typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined' : boolean
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+>typeof u.key1?.key2 !== 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | undefined
+>u.key1 : { key2: string; } | undefined
+>u : Foo1 | Foo2
+>key1 : { key2: string; } | undefined
+>key2 : string | undefined
+>'undefined' : "undefined"
+
+        u;    //U1
+>u : U1
+    }
+}
+
+// root optional chain
+function f3(u: U2) {
+>f3 : (u: U2) => void
+>u : U2
+
+    if (typeof u?.key1 !== 'number') {
+>typeof u?.key1 !== 'number' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'number' : "number"
+
+        u;  //U2
+>u : U2
+    }
+    if (typeof u?.key1 === 'number') {
+>typeof u?.key1 === 'number' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'number' : "number"
+
+        u;  //never
+>u : never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+>typeof u?.key1 !== 'undefined' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'undefined' : "undefined"
+
+        u;  //Foo1 | Foo2 | Foo3
+>u : Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1 === 'undefined') {
+>typeof u?.key1 === 'undefined' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'undefined' : "undefined"
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Foo1 | Foo2 | undefined
+    }
+}
+
+// multi optional chain
+function f4(u: U2) {
+>f4 : (u: U2) => void
+>u : U2
+
+    if (typeof u?.key1?.key2 !== 'number') {
+>typeof u?.key1?.key2 !== 'number' : boolean
+>typeof u?.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1?.key2 : string | number | undefined
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Foo1 | Foo2 | undefined
+    }
+    if (typeof u?.key1?.key2 === 'number') {
+>typeof u?.key1?.key2 === 'number' : boolean
+>typeof u?.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1?.key2 : string | number | undefined
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+
+        u;  //Foo1 | Foo3
+>u : Foo1 | Foo3
+    }
+    if (typeof u?.key1?.key2 !== 'undefined') {
+>typeof u?.key1?.key2 !== 'undefined' : boolean
+>typeof u?.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1?.key2 : string | number | undefined
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+
+        u;  //Foo1 | Foo2 | Foo3
+>u : Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1?.key2 === 'undefined') {
+>typeof u?.key1?.key2 === 'undefined' : boolean
+>typeof u?.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1?.key2 : string | number | undefined
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Foo1 | Foo2 | undefined
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.errors.txt b/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.errors.txt
new file mode 100644
index 0000000000000..eabfa1f27f84b
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.errors.txt
@@ -0,0 +1,112 @@
+tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptionalBySwitch.ts(58,63): error TS2339: Property 'key2' does not exist on type 'never'.
+
+
+==== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptionalBySwitch.ts (1 errors) ====
+    interface Foo1 {
+        key1: {
+            key2: number;
+        } | undefined;
+        f1: number;
+    }
+    
+    interface Foo2 {
+        key1: {
+            key2: string
+        } | undefined;
+        f2: number;
+    }
+    
+    interface Foo3 {
+        key1: {
+            key2: number;
+        };
+        f2: number;
+    }
+    type U1 = Foo1 | Foo2 | Foo3;
+    type U2 = Foo1 | Foo2 | Foo3 | undefined;
+    
+    
+    // unnecessary optional chain
+    function f1(u: U1) {
+        if (typeof u?.key1 !== 'number') {
+            u;  // U1
+        }
+        if (typeof u?.key1 === 'number') {
+            u;  // never
+        }
+        if (typeof u?.key1 !== 'undefined') {
+            u;  // U1
+        }
+        if (typeof u?.key1 === 'undefined') {
+            u;  // Foo1 | Foo2
+        }
+    }
+    
+    // non-root optional chain
+    function f2(u: U1) {
+        if (typeof u.key1?.key2 !== 'number') {
+            u;  //Foo1 | Foo2
+        }
+        if (typeof u.key1?.key2 === 'number') {
+            u;  //Foo1 | Foo3
+        }
+        if (typeof u.key1?.key2 !== 'undefined') {
+            u;  //U1
+        }
+        if (typeof u.key1?.key2 === 'undefined') {
+            u;  //Foo1 | Foo2
+        }
+    }
+    
+    function f2Plus(u: U1) {
+        if (typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number') {
+                                                                  ~~~~
+!!! error TS2339: Property 'key2' does not exist on type 'never'.
+            u;    // should be never, but this should be a design limit?
+        }
+        if (typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number') {
+            u;    //U1
+        }
+        if (typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined') {
+            u;    // should be never, but this should be a design limit?
+        }
+        if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined') {
+            u;    //U1
+        }
+        if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined') {
+            u;    //U1
+        }
+    }
+    
+    // root optional chain
+    function f3(u: U2) {
+        if (typeof u?.key1 !== 'number') {
+            u;  //U2
+        }
+        if (typeof u?.key1 === 'number') {
+            u;  //never
+        }
+        if (typeof u?.key1 !== 'undefined') {
+            u;  //Foo1 | Foo2 | Foo3
+        }
+        if (typeof u?.key1 === 'undefined') {
+            u;  //Foo1 | Foo2 | Undefined
+        }
+    }
+    
+    // multi optional chain
+    function f4(u: U2) {
+        if (typeof u?.key1?.key2 !== 'number') {
+            u;  //Foo1 | Foo2 | Undefined
+        }
+        if (typeof u?.key1?.key2 === 'number') {
+            u;  //Foo1 | Foo3
+        }
+        if (typeof u?.key1?.key2 !== 'undefined') {
+            u;  //Foo1 | Foo2 | Foo3
+        }
+        if (typeof u?.key1?.key2 === 'undefined') {
+            u;  //Foo1 | Foo2 | Undefined
+        }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.js b/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.js
new file mode 100644
index 0000000000000..a625fab9d0d7b
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.js
@@ -0,0 +1,190 @@
+//// [typeGuardAccordingToPropertyOptionalBySwitch.ts]
+interface Foo1 {
+    key1: {
+        key2: number;
+    } | undefined;
+    f1: number;
+}
+
+interface Foo2 {
+    key1: {
+        key2: string
+    } | undefined;
+    f2: number;
+}
+
+interface Foo3 {
+    key1: {
+        key2: number;
+    };
+    f2: number;
+}
+type U1 = Foo1 | Foo2 | Foo3;
+type U2 = Foo1 | Foo2 | Foo3 | undefined;
+
+
+// unnecessary optional chain
+function f1(u: U1) {
+    if (typeof u?.key1 !== 'number') {
+        u;  // U1
+    }
+    if (typeof u?.key1 === 'number') {
+        u;  // never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+        u;  // U1
+    }
+    if (typeof u?.key1 === 'undefined') {
+        u;  // Foo1 | Foo2
+    }
+}
+
+// non-root optional chain
+function f2(u: U1) {
+    if (typeof u.key1?.key2 !== 'number') {
+        u;  //Foo1 | Foo2
+    }
+    if (typeof u.key1?.key2 === 'number') {
+        u;  //Foo1 | Foo3
+    }
+    if (typeof u.key1?.key2 !== 'undefined') {
+        u;  //U1
+    }
+    if (typeof u.key1?.key2 === 'undefined') {
+        u;  //Foo1 | Foo2
+    }
+}
+
+function f2Plus(u: U1) {
+    if (typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number') {
+        u;    // should be never, but this should be a design limit?
+    }
+    if (typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number') {
+        u;    //U1
+    }
+    if (typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined') {
+        u;    // should be never, but this should be a design limit?
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined') {
+        u;    //U1
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined') {
+        u;    //U1
+    }
+}
+
+// root optional chain
+function f3(u: U2) {
+    if (typeof u?.key1 !== 'number') {
+        u;  //U2
+    }
+    if (typeof u?.key1 === 'number') {
+        u;  //never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+        u;  //Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1 === 'undefined') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+}
+
+// multi optional chain
+function f4(u: U2) {
+    if (typeof u?.key1?.key2 !== 'number') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+    if (typeof u?.key1?.key2 === 'number') {
+        u;  //Foo1 | Foo3
+    }
+    if (typeof u?.key1?.key2 !== 'undefined') {
+        u;  //Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1?.key2 === 'undefined') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+}
+
+
+//// [typeGuardAccordingToPropertyOptionalBySwitch.js]
+"use strict";
+// unnecessary optional chain
+function f1(u) {
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) !== 'number') {
+        u; // U1
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) === 'number') {
+        u; // never
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) !== 'undefined') {
+        u; // U1
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) === 'undefined') {
+        u; // Foo1 | Foo2
+    }
+}
+// non-root optional chain
+function f2(u) {
+    var _a, _b, _c, _d;
+    if (typeof ((_a = u.key1) === null || _a === void 0 ? void 0 : _a.key2) !== 'number') {
+        u; //Foo1 | Foo2
+    }
+    if (typeof ((_b = u.key1) === null || _b === void 0 ? void 0 : _b.key2) === 'number') {
+        u; //Foo1 | Foo3
+    }
+    if (typeof ((_c = u.key1) === null || _c === void 0 ? void 0 : _c.key2) !== 'undefined') {
+        u; //U1
+    }
+    if (typeof ((_d = u.key1) === null || _d === void 0 ? void 0 : _d.key2) === 'undefined') {
+        u; //Foo1 | Foo2
+    }
+}
+function f2Plus(u) {
+    var _a, _b, _c, _d, _e, _f, _g, _h, _j, _k;
+    if (typeof ((_a = u.key1) === null || _a === void 0 ? void 0 : _a.key2) === 'undefined' && typeof ((_b = u.key1) === null || _b === void 0 ? void 0 : _b.key2) === 'number') {
+        u; // should be never, but this should be a design limit?
+    }
+    if (typeof ((_c = u.key1) === null || _c === void 0 ? void 0 : _c.key2) === 'undefined' || typeof ((_d = u.key1) === null || _d === void 0 ? void 0 : _d.key2) === 'number') {
+        u; //U1
+    }
+    if (typeof ((_e = u.key1) === null || _e === void 0 ? void 0 : _e.key2) === 'number' && typeof ((_f = u.key1) === null || _f === void 0 ? void 0 : _f.key2) === 'undefined') {
+        u; // should be never, but this should be a design limit?
+    }
+    if (typeof ((_g = u.key1) === null || _g === void 0 ? void 0 : _g.key2) === 'number' || typeof ((_h = u.key1) === null || _h === void 0 ? void 0 : _h.key2) === 'undefined') {
+        u; //U1
+    }
+    if (typeof ((_j = u.key1) === null || _j === void 0 ? void 0 : _j.key2) === 'number' || typeof ((_k = u.key1) === null || _k === void 0 ? void 0 : _k.key2) !== 'undefined') {
+        u; //U1
+    }
+}
+// root optional chain
+function f3(u) {
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) !== 'number') {
+        u; //U2
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) === 'number') {
+        u; //never
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) !== 'undefined') {
+        u; //Foo1 | Foo2 | Foo3
+    }
+    if (typeof (u === null || u === void 0 ? void 0 : u.key1) === 'undefined') {
+        u; //Foo1 | Foo2 | Undefined
+    }
+}
+// multi optional chain
+function f4(u) {
+    var _a, _b, _c, _d;
+    if (typeof ((_a = u === null || u === void 0 ? void 0 : u.key1) === null || _a === void 0 ? void 0 : _a.key2) !== 'number') {
+        u; //Foo1 | Foo2 | Undefined
+    }
+    if (typeof ((_b = u === null || u === void 0 ? void 0 : u.key1) === null || _b === void 0 ? void 0 : _b.key2) === 'number') {
+        u; //Foo1 | Foo3
+    }
+    if (typeof ((_c = u === null || u === void 0 ? void 0 : u.key1) === null || _c === void 0 ? void 0 : _c.key2) !== 'undefined') {
+        u; //Foo1 | Foo2 | Foo3
+    }
+    if (typeof ((_d = u === null || u === void 0 ? void 0 : u.key1) === null || _d === void 0 ? void 0 : _d.key2) === 'undefined') {
+        u; //Foo1 | Foo2 | Undefined
+    }
+}
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.symbols b/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.symbols
new file mode 100644
index 0000000000000..7381ba8a7da86
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.symbols
@@ -0,0 +1,311 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptionalBySwitch.ts ===
+interface Foo1 {
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 0))
+
+    key1: {
+>key1 : Symbol(Foo1.key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16))
+
+        key2: number;
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11))
+
+    } | undefined;
+    f1: number;
+>f1 : Symbol(Foo1.f1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 3, 18))
+}
+
+interface Foo2 {
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 5, 1))
+
+    key1: {
+>key1 : Symbol(Foo2.key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16))
+
+        key2: string
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+
+    } | undefined;
+    f2: number;
+>f2 : Symbol(Foo2.f2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 10, 18))
+}
+
+interface Foo3 {
+>Foo3 : Symbol(Foo3, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 12, 1))
+
+    key1: {
+>key1 : Symbol(Foo3.key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+
+        key2: number;
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+
+    };
+    f2: number;
+>f2 : Symbol(Foo3.f2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 17, 6))
+}
+type U1 = Foo1 | Foo2 | Foo3;
+>U1 : Symbol(U1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 19, 1))
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 0))
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 5, 1))
+>Foo3 : Symbol(Foo3, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 12, 1))
+
+type U2 = Foo1 | Foo2 | Foo3 | undefined;
+>U2 : Symbol(U2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 20, 29))
+>Foo1 : Symbol(Foo1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 0))
+>Foo2 : Symbol(Foo2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 5, 1))
+>Foo3 : Symbol(Foo3, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 12, 1))
+
+
+// unnecessary optional chain
+function f1(u: U1) {
+>f1 : Symbol(f1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 21, 41))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 25, 12))
+>U1 : Symbol(U1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 19, 1))
+
+    if (typeof u?.key1 !== 'number') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 25, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+
+        u;  // U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 25, 12))
+    }
+    if (typeof u?.key1 === 'number') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 25, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+
+        u;  // never
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 25, 12))
+    }
+    if (typeof u?.key1 !== 'undefined') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 25, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+
+        u;  // U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 25, 12))
+    }
+    if (typeof u?.key1 === 'undefined') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 25, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+
+        u;  // Foo1 | Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 25, 12))
+    }
+}
+
+// non-root optional chain
+function f2(u: U1) {
+>f2 : Symbol(f2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 38, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 41, 12))
+>U1 : Symbol(U1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 19, 1))
+
+    if (typeof u.key1?.key2 !== 'number') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 41, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+
+        u;  //Foo1 | Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 41, 12))
+    }
+    if (typeof u.key1?.key2 === 'number') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 41, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+
+        u;  //Foo1 | Foo3
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 41, 12))
+    }
+    if (typeof u.key1?.key2 !== 'undefined') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 41, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+
+        u;  //U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 41, 12))
+    }
+    if (typeof u.key1?.key2 === 'undefined') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 41, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+
+        u;  //Foo1 | Foo2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 41, 12))
+    }
+}
+
+function f2Plus(u: U1) {
+>f2Plus : Symbol(f2Plus, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 54, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>U1 : Symbol(U1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 19, 1))
+
+    if (typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16))
+
+        u;    // should be never, but this should be a design limit?
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+    }
+    if (typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+
+        u;    //U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+    }
+    if (typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11))
+
+        u;    // should be never, but this should be a design limit?
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+
+        u;    //U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined') {
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+>u.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+>u.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11))
+
+        u;    //U1
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 56, 16))
+    }
+}
+
+// root optional chain
+function f3(u: U2) {
+>f3 : Symbol(f3, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 72, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 75, 12))
+>U2 : Symbol(U2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 20, 29))
+
+    if (typeof u?.key1 !== 'number') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 75, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+
+        u;  //U2
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 75, 12))
+    }
+    if (typeof u?.key1 === 'number') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 75, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+
+        u;  //never
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 75, 12))
+    }
+    if (typeof u?.key1 !== 'undefined') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 75, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+
+        u;  //Foo1 | Foo2 | Foo3
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 75, 12))
+    }
+    if (typeof u?.key1 === 'undefined') {
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 75, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 75, 12))
+    }
+}
+
+// multi optional chain
+function f4(u: U2) {
+>f4 : Symbol(f4, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 88, 1))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 91, 12))
+>U2 : Symbol(U2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 20, 29))
+
+    if (typeof u?.key1?.key2 !== 'number') {
+>u?.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 91, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 91, 12))
+    }
+    if (typeof u?.key1?.key2 === 'number') {
+>u?.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 91, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+
+        u;  //Foo1 | Foo3
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 91, 12))
+    }
+    if (typeof u?.key1?.key2 !== 'undefined') {
+>u?.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 91, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+
+        u;  //Foo1 | Foo2 | Foo3
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 91, 12))
+    }
+    if (typeof u?.key1?.key2 === 'undefined') {
+>u?.key1?.key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+>u?.key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 91, 12))
+>key1 : Symbol(key1, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 0, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 7, 16), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 14, 16))
+>key2 : Symbol(key2, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 1, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 8, 11), Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 15, 11))
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Symbol(u, Decl(typeGuardAccordingToPropertyOptionalBySwitch.ts, 91, 12))
+    }
+}
+
diff --git a/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.types b/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.types
new file mode 100644
index 0000000000000..99739475d9d44
--- /dev/null
+++ b/tests/baselines/reference/typeGuardAccordingToPropertyOptionalBySwitch.types
@@ -0,0 +1,379 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptionalBySwitch.ts ===
+interface Foo1 {
+    key1: {
+>key1 : { key2: number; } | undefined
+
+        key2: number;
+>key2 : number
+
+    } | undefined;
+    f1: number;
+>f1 : number
+}
+
+interface Foo2 {
+    key1: {
+>key1 : { key2: string; } | undefined
+
+        key2: string
+>key2 : string
+
+    } | undefined;
+    f2: number;
+>f2 : number
+}
+
+interface Foo3 {
+    key1: {
+>key1 : { key2: number; }
+
+        key2: number;
+>key2 : number
+
+    };
+    f2: number;
+>f2 : number
+}
+type U1 = Foo1 | Foo2 | Foo3;
+>U1 : U1
+
+type U2 = Foo1 | Foo2 | Foo3 | undefined;
+>U2 : U2
+
+
+// unnecessary optional chain
+function f1(u: U1) {
+>f1 : (u: U1) => void
+>u : U1
+
+    if (typeof u?.key1 !== 'number') {
+>typeof u?.key1 !== 'number' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'number' : "number"
+
+        u;  // U1
+>u : U1
+    }
+    if (typeof u?.key1 === 'number') {
+>typeof u?.key1 === 'number' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'number' : "number"
+
+        u;  // never
+>u : never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+>typeof u?.key1 !== 'undefined' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'undefined' : "undefined"
+
+        u;  // U1
+>u : U1
+    }
+    if (typeof u?.key1 === 'undefined') {
+>typeof u?.key1 === 'undefined' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'undefined' : "undefined"
+
+        u;  // Foo1 | Foo2
+>u : Foo1 | Foo2
+    }
+}
+
+// non-root optional chain
+function f2(u: U1) {
+>f2 : (u: U1) => void
+>u : U1
+
+    if (typeof u.key1?.key2 !== 'number') {
+>typeof u.key1?.key2 !== 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+
+        u;  //Foo1 | Foo2
+>u : Foo1 | Foo2
+    }
+    if (typeof u.key1?.key2 === 'number') {
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+
+        u;  //Foo1 | Foo3
+>u : Foo1 | Foo3
+    }
+    if (typeof u.key1?.key2 !== 'undefined') {
+>typeof u.key1?.key2 !== 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+
+        u;  //U1
+>u : U1
+    }
+    if (typeof u.key1?.key2 === 'undefined') {
+>typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+
+        u;  //Foo1 | Foo2
+>u : Foo1 | Foo2
+    }
+}
+
+function f2Plus(u: U1) {
+>f2Plus : (u: U1) => void
+>u : U1
+
+    if (typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number') {
+>typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : any
+>u.key1 : undefined
+>u : Foo1 | Foo2
+>key1 : undefined
+>key2 : any
+>'number' : "number"
+
+        u;    // should be never, but this should be a design limit?
+>u : Foo1
+    }
+    if (typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number') {
+>typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number
+>u.key1 : { key2: number; } | { key2: string; } | { key2: number; }
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | { key2: number; }
+>key2 : string | number
+>'number' : "number"
+
+        u;    //U1
+>u : U1
+    }
+    if (typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined') {
+>typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+>typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : number
+>u.key1 : { key2: number; }
+>u : Foo1 | Foo3
+>key1 : { key2: number; }
+>key2 : number
+>'undefined' : "undefined"
+
+        u;    // should be never, but this should be a design limit?
+>u : Foo1
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined') {
+>typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+>typeof u.key1?.key2 === 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | undefined
+>u.key1 : { key2: string; } | undefined
+>u : Foo1 | Foo2
+>key1 : { key2: string; } | undefined
+>key2 : string | undefined
+>'undefined' : "undefined"
+
+        u;    //U1
+>u : U1
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined') {
+>typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined' : boolean
+>typeof u.key1?.key2 === 'number' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | number | undefined
+>u.key1 : { key2: number; } | { key2: string; } | undefined
+>u : U1
+>key1 : { key2: number; } | { key2: string; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+>typeof u.key1?.key2 !== 'undefined' : boolean
+>typeof u.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u.key1?.key2 : string | undefined
+>u.key1 : { key2: string; } | undefined
+>u : Foo1 | Foo2
+>key1 : { key2: string; } | undefined
+>key2 : string | undefined
+>'undefined' : "undefined"
+
+        u;    //U1
+>u : U1
+    }
+}
+
+// root optional chain
+function f3(u: U2) {
+>f3 : (u: U2) => void
+>u : U2
+
+    if (typeof u?.key1 !== 'number') {
+>typeof u?.key1 !== 'number' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'number' : "number"
+
+        u;  //U2
+>u : U2
+    }
+    if (typeof u?.key1 === 'number') {
+>typeof u?.key1 === 'number' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'number' : "number"
+
+        u;  //never
+>u : never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+>typeof u?.key1 !== 'undefined' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'undefined' : "undefined"
+
+        u;  //Foo1 | Foo2 | Foo3
+>u : Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1 === 'undefined') {
+>typeof u?.key1 === 'undefined' : boolean
+>typeof u?.key1 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>'undefined' : "undefined"
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Foo1 | Foo2 | undefined
+    }
+}
+
+// multi optional chain
+function f4(u: U2) {
+>f4 : (u: U2) => void
+>u : U2
+
+    if (typeof u?.key1?.key2 !== 'number') {
+>typeof u?.key1?.key2 !== 'number' : boolean
+>typeof u?.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1?.key2 : string | number | undefined
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Foo1 | Foo2 | undefined
+    }
+    if (typeof u?.key1?.key2 === 'number') {
+>typeof u?.key1?.key2 === 'number' : boolean
+>typeof u?.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1?.key2 : string | number | undefined
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'number' : "number"
+
+        u;  //Foo1 | Foo3
+>u : Foo1 | Foo3
+    }
+    if (typeof u?.key1?.key2 !== 'undefined') {
+>typeof u?.key1?.key2 !== 'undefined' : boolean
+>typeof u?.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1?.key2 : string | number | undefined
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+
+        u;  //Foo1 | Foo2 | Foo3
+>u : Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1?.key2 === 'undefined') {
+>typeof u?.key1?.key2 === 'undefined' : boolean
+>typeof u?.key1?.key2 : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>u?.key1?.key2 : string | number | undefined
+>u?.key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>u : U2
+>key1 : { key2: number; } | { key2: string; } | { key2: number; } | undefined
+>key2 : string | number | undefined
+>'undefined' : "undefined"
+
+        u;  //Foo1 | Foo2 | Undefined
+>u : Foo1 | Foo2 | undefined
+    }
+}
+
diff --git a/tests/cases/compiler/nonNullReferenceMatching.ts b/tests/cases/compiler/nonNullReferenceMatching.ts
index 1295c3ce9a7f7..eb7762b0c1d13 100644
--- a/tests/cases/compiler/nonNullReferenceMatching.ts
+++ b/tests/cases/compiler/nonNullReferenceMatching.ts
@@ -10,6 +10,14 @@ type ComponentProps = {
     thumbXProps: ThumbProps;
 }
 
+type ThumbProps2 = {
+    elementRef: ElementRef | null;
+}
+
+type ComponentProps2 = {
+    thumbYProps: ThumbProps2 | null;
+}
+
 class Component {
     props!: ComponentProps;
     public thumbYElementRef = (ref: HTMLElement | null) => {
@@ -31,4 +39,15 @@ class Component {
 
         typeof this.props!.thumbXProps!.elementRef === 'function' && ((this.props)!.thumbXProps)!.elementRef(ref);
     };
+}
+
+class Component2 {
+    props!: ComponentProps2;
+    public thumbYElementRef = (ref: HTMLElement | null) => {
+        typeof this.props.thumbYProps!.elementRef === 'function' && this.props.thumbYProps!.elementRef(ref);
+
+        typeof (this.props.thumbYProps!.elementRef) === 'function' && this.props.thumbYProps!.elementRef(ref);
+
+        typeof ((this.props).thumbYProps!.elementRef)! === 'function' && this.props.thumbYProps!.elementRef(ref);
+    }
 }
\ No newline at end of file
diff --git a/tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts b/tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts
index e5495a313aa0d..b6d7a04800d2b 100644
--- a/tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts
+++ b/tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts
@@ -518,7 +518,7 @@ function f41(o: Thing | undefined) {
             o.foo;  // Error
             break;
         default:
-            o.foo;  // Error
+            o.foo;
             break;
     }
 }
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty.ts
new file mode 100644
index 0000000000000..d5b78fc3306c6
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty.ts
@@ -0,0 +1,259 @@
+// @strict: true
+
+// Primitive value ---- boolean bigint number string symbol undefined function object
+// ts special type ---- any, void, unknown, union, intersection
+
+//// Property Access ---- a.b
+//// Element Access ---- a["b"]
+
+interface Boolean1 {
+    key: boolean;
+    b1: number;
+};
+
+interface Boolean2 {
+    key: boolean;
+    b2: number;
+};
+
+interface BigInt1 {
+    key: bigint;
+    bi1: number;
+};
+
+interface Number1 {
+    key: number;
+    n1: number;
+};
+
+interface String1 {
+    key: string;
+    st1: number;
+}
+
+interface Symbol1 {
+    key: symbol;
+    sy1: number;
+}
+
+interface Undefined1 {
+    key: undefined;
+    u1: number;
+}
+
+interface Function1 {
+    key: () => void;
+    f1: number;
+}
+
+interface Obejct1 {
+    key: {
+        notEmpty: number;
+    };
+    o1: number;
+}
+
+type Union1 = Boolean1 | Boolean2 | Number1;
+type Union2 = Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1;
+
+function f1_1(u: Union1) {
+    if (typeof u.key !== 'boolean') {
+        u;      // Number1
+        u.n1;   // number
+    }
+}
+function f1_2(u: Union1) {
+    if (typeof u.key === 'boolean') {
+        u;      // Bolean1 | Bolean2
+        u.b1;   // Error
+        u.b2;   // Error
+    }
+}
+
+function f1ElementAccess_1(u: Union1) {
+    if (typeof u["key"] !== 'boolean') {
+        u;      // Number1
+        u.n1;   // number
+    }
+}
+function f1ElementAccess_2(u: Union1) {
+    if (typeof u["key"] === 'boolean') {
+        u;      // Bolean1 | Bolean2
+        u.b1;   // Error
+        u.b2;   // Error
+    }
+}
+
+function f1_Plus(u: Union1) {
+    if (typeof u.key !== 'boolean') {
+        throw new Error();
+    }
+    u;  // Bolean1 | Bolean2
+    if (typeof u.key === 'boolean') {
+        throw new Error();
+    }
+    u;  // never
+}
+
+// boolean bigint number string symbol undefined function object
+function f2_1(u: Union2) {
+    if (typeof u.key === 'bigint') {
+        u;      // BigInt1
+        u.bi1;
+    }
+    if (typeof u.key == 'bigint') {
+        u;      // BigInt1
+        u.bi1;
+    }
+}
+function f2_2(u: Union2) {
+    if (typeof u.key === 'boolean') {
+        u;      // Boolean1
+        u.b1;
+    }
+    if (typeof u.key == 'boolean') {
+        u;      // Boolean1
+        u.b1;
+    }
+}
+function f2_3(u: Union2) {
+    if (typeof u.key === 'number') {
+        u;      // Number1
+        u.n1;
+    }
+    if (typeof u.key == 'number') {
+        u;      // Number1
+        u.n1;
+    }
+}
+function f2_4(u: Union2) {
+    if (typeof u.key === 'string') {
+        u;      // String1
+        u.st1;
+    }
+    if (typeof u.key == 'string') {
+        u;      // String1
+        u.st1;
+    }
+}
+function f2_5(u: Union2) {
+    if (typeof u.key === 'symbol') {
+        u;      // Symbol1
+        u.sy1;
+    }
+    if (typeof u.key == 'symbol') {
+        u;      // Symbol1
+        u.sy1;
+    }
+}
+function f2_6(u: Union2) {
+    if (typeof u.key === 'undefined') {
+        u;      // Undefined1
+        u.u1
+    }
+    if (typeof u.key == 'undefined') {
+        u;      // Undefined1
+        u.u1
+    }
+}
+function f2_7(u: Union2) {
+    if (typeof u.key === 'function') {
+        u;      // Function1
+        u.f1;
+    }
+    if (typeof u.key == 'function') {
+        u;      // Function1
+        u.f1;
+    }
+}
+function f2_8(u: Union2) {
+    if (typeof u.key === 'object') {
+        u;      // Object1
+        u.o1;
+    }
+    if (typeof u.key == 'object') {
+        u;      // Object1
+        u.o1;
+    }
+}
+
+function f2Not_1(u: Union2) {
+    if (typeof u.key !== 'bigint') {
+        u;      // not BigInt1
+    }
+    if (typeof u.key != 'bigint') {
+        u;      // not BigInt1
+    }
+}
+function f2Not_2(u: Union2) {
+    if (typeof u.key !== 'boolean') {
+        u;      // not Boolean1
+    }
+    if (typeof u.key != 'boolean') {
+        u;      // not Boolean1
+    }
+}
+
+function f2Not_3(u: Union2) {
+    if (typeof u.key !== 'number') {
+        u;      // not Number1
+    }
+    if (typeof u.key != 'number') {
+        u;      // not Number1
+    }
+}
+
+function f2Not_4(u: Union2) {
+    if (typeof u.key !== 'string') {
+        u;      // not String1
+    }
+    if (typeof u.key != 'string') {
+        u;      // not String1
+    }
+}
+
+function f2Not_5(u: Union2) {
+    if (typeof u.key !== 'symbol') {
+        u;      // not Symbol1
+    }
+    if (typeof u.key != 'symbol') {
+        u;      // not Symbol1
+    }
+}
+
+function f2Not_6(u: Union2) {
+    if (typeof u.key !== 'undefined') {
+        u;      // not Undefined1
+    }
+    if (typeof u.key != 'undefined') {
+        u;      // not Undefined1
+    }
+}
+
+function f2Not_7(u: Union2) {
+    if (typeof u.key !== 'function') {
+        u;      // not Function1
+    }
+    if (typeof u.key != 'function') {
+        u;      // not Function1
+    }
+}
+
+function f2Not_8(u: Union2) {
+    if (typeof u.key !== 'object') {
+        u;      // not Object1
+    }
+    if (typeof u.key != 'object') {
+        u;      // not Object1
+    }
+}
+
+interface A { x: string, y: string };
+interface B { x: number, y: number };
+type X = A | B;
+
+function f3(bar: X) {
+    if (typeof bar.x === 'string') {
+        let y = bar.y; // string
+    }
+}
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty2.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty2.ts
new file mode 100644
index 0000000000000..276c89b4c580c
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToProperty2.ts
@@ -0,0 +1,27 @@
+// @strict: true
+
+interface A {
+    kind: 'A';
+    symbol: object;
+    fileName: string;
+}
+
+interface B {
+    kind: 'B';
+}
+
+declare var s: A | B;
+
+if (s.kind === 'A') {
+    if (s.symbol) {     // this is a truthy condition, we could narrow it, but it has a property `symbol`, so do nothing.
+        s;    // A
+    } else {
+        s.fileName;  // A
+    }
+
+    if (s) {    // this is another truthy condition, now it is alone, so narrow it.
+        s; // A
+    } else {
+        s; // never
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyBySwitch.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyBySwitch.ts
new file mode 100644
index 0000000000000..d18eaeb54a6b6
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyBySwitch.ts
@@ -0,0 +1,180 @@
+// @strict: true
+
+// Primitive value ---- boolean bigint number string symbol undefined function object
+// ts special type ---- any, void, unknown, union, intersection
+
+//// Property Access ---- a.b
+//// Element Access ---- a["b"]
+
+interface Boolean1 {
+    key: boolean;
+    b1: number;
+};
+
+interface Boolean2 {
+    key: boolean;
+    b2: number;
+};
+
+interface BigInt1 {
+    key: bigint;
+    bi1: number;
+};
+
+interface Number1 {
+    key: number;
+    n1: number;
+};
+
+interface String1 {
+    key: string;
+    st1: number;
+}
+
+interface Symbol1 {
+    key: symbol;
+    sy1: number;
+}
+
+interface Undefined1 {
+    key: undefined;
+    u1: number;
+}
+
+interface Function1 {
+    key: () => void;
+    f1: number;
+}
+
+interface Obejct1 {
+    key: {
+        notEmpty: number;
+    };
+    o1: number;
+}
+
+type Union1 = Boolean1 | Boolean2 | Number1;
+type Union2 = Boolean1 | BigInt1 | Number1 | String1 | Symbol1 | Undefined1 | Function1 | Obejct1;
+
+function f1_1(u: Union1) {
+    switch (typeof u.key) {
+        case 'boolean':
+            u;    // Boolean1 | Boolean2
+            break;
+        case 'number':
+            u;    // Number1
+            break;
+        default:
+            u;    // never
+            break;
+    }
+}
+
+function f1_2(u: Union1) {
+    switch (typeof u.key) {
+        case 'boolean':
+            u;    // Boolean1 | Boolean2
+            break;
+        default:
+            u;    // Number1
+            break;
+    }
+}
+
+
+function f1ElementAccess_1(u: Union1) {
+    if (typeof u["key"] !== 'boolean') {
+        u;      // Number1
+        u.n1;   // number
+    }
+}
+
+// boolean bigint number string symbol undefined function object
+function f2_1(u: Union2) {
+    switch (typeof u.key) {
+        case 'bigint':
+            u;  // Bigint1
+            break;
+        case 'boolean':
+            u;  // Boolean1
+            break;
+        case 'number':
+            u;  // Number1
+            break;
+        case 'string':
+            u;  // String1
+            break;
+        case 'symbol':
+            u;  // Symbol1
+            break;
+        case 'undefined':
+            u;  // Undefined1
+            break;
+        case 'function':
+            u;  // Function1
+            break;
+        case 'object':
+            u;  // Object1
+            break;
+    }
+}
+
+function f2_2(u: Union2) {
+    switch (typeof u.key) {
+        case 'bigint':
+        case 'boolean':
+        case 'number':
+        case 'string':
+            u;  // Boolean1 | Number1 | BigInt1 | String1
+            break;
+        case 'symbol':
+        case 'undefined':
+        case 'function':
+        case 'object':
+            u;   // Symbol1 | Undefined1 | Function1 | Obejct1
+            break;
+    }
+}
+
+function f2_3(u: Union2) {
+    switch (typeof u.key) {
+        case 'bigint':
+        case 'boolean':
+        case 'number':
+        case 'string':
+            u;  // Boolean1 | Number1 | BigInt1 | String1
+            break;
+        default:
+            u;  // Symbol1 | Undefined1 | Function1 | Obejct1
+            break;
+    }
+}
+
+function f2_4(u: Union2) {
+    switch (typeof u.key) {
+        case 'symbol':
+        case 'undefined':
+        case 'function':
+        case 'object':
+            u;  // Symbol1 | Undefined1 | Function1 | Obejct1
+            break;
+        default:
+            u;  // Boolean1 | BigInt1 | Number1 | String1
+            break;
+    }
+}
+
+interface A { x: string, y: string };
+interface B { x: number, y: number };
+type X = A | B;
+
+function f3(bar: X) {
+    switch (typeof bar.x) {
+        case 'string':
+            let y = bar.y; // string
+            break;
+        default:
+            bar.y;
+            break;
+    }
+}
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyDeep.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyDeep.ts
new file mode 100644
index 0000000000000..2ce4135da4a78
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyDeep.ts
@@ -0,0 +1,55 @@
+// @strict: true
+
+//// deep property access ---- a.b.c.d.e.f, a["b"]["c"]["d"]
+//// mix deep property access ---- a.b["c"]["d"].e
+
+interface Foo1 {
+    firstKey: number,
+    inner: {
+        secondKey: number,
+        f1: number
+    }
+}
+
+interface Foo2 {
+    firstKey: boolean,
+    inner: {
+        secondKey: boolean,
+        f2: number
+    }
+}
+
+interface Foo3 {
+    firstKey: string;
+}
+
+type Union = Foo1 | Foo2 | Foo3;
+
+function f(u: Union) {
+    if (typeof u.firstKey === "number" || typeof u.firstKey === "boolean") {
+        u;  // Foo1 | Foo2
+        if (typeof u.inner.secondKey === "boolean") {
+            u;  // Foo2
+        }
+    }
+}
+
+type Union2 = Foo1 | Foo2;
+
+function f2(u: Union2) {
+    if (typeof u.inner["secondKey"] === "boolean") {
+        u;  // Foo2
+    }
+}
+
+function f3(u: Union2) {
+    if (typeof u["inner"]["secondKey"] === "boolean") {
+        u;  // Foo2
+    }
+}
+
+function f4(u: Union2) {
+    if (typeof u["inner"].secondKey === "boolean") {
+        u;  // Foo2
+    }
+}
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyDeepBySwitch.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyDeepBySwitch.ts
new file mode 100644
index 0000000000000..80ef4372c177a
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyDeepBySwitch.ts
@@ -0,0 +1,49 @@
+// @strict: true
+
+interface Foo1 {
+    firstKey: number,
+    inner: {
+        secondKey: number,
+        f1: number
+    }
+}
+
+interface Foo2 {
+    firstKey: boolean,
+    inner: {
+        secondKey: boolean,
+        f2: number
+    }
+}
+
+interface Foo3 {
+    firstKey: string;
+}
+
+type Union = Foo1 | Foo2 | Foo3;
+
+function f(u: Union) {
+    switch (typeof u.firstKey) {
+        case 'number':
+        case 'boolean':
+            u;
+            switch (typeof u.inner.secondKey) {
+                case 'boolean':
+                    u;
+            }
+    }
+}
+
+type Union2 = Foo1 | Foo2;
+
+// fall through
+function f2(u: Union2) {
+    switch (typeof u.inner["secondKey"]) {
+        case 'boolean':
+            u;  // never
+        case 'bigint':
+            u;  // Foo2
+        default:
+            u;  // Union2
+    }
+}
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptional.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptional.ts
new file mode 100644
index 0000000000000..80807e9498e41
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptional.ts
@@ -0,0 +1,109 @@
+// @strict: true
+
+
+
+interface Foo1 {
+    key1: {
+        key2: number;
+    } | undefined;
+    f1: number;
+}
+
+interface Foo2 {
+    key1: {
+        key2: string
+    } | undefined;
+    f2: number;
+}
+
+interface Foo3 {
+    key1: {
+        key2: number;
+    };
+    f2: number;
+}
+type U1 = Foo1 | Foo2 | Foo3;
+type U2 = Foo1 | Foo2 | Foo3 | undefined;
+
+
+// unnecessary optional chain
+function f1(u: U1) {
+    if (typeof u?.key1 !== 'number') {
+        u;  // U1
+    }
+    if (typeof u?.key1 === 'number') {
+        u;  // never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+        u;  // U1
+    }
+    if (typeof u?.key1 === 'undefined') {
+        u;  // Foo1 | Foo2
+    }
+}
+
+// non-root optional chain
+function f2(u: U1) {
+    if (typeof u.key1?.key2 !== 'number') {
+        u;  //Foo1 | Foo2
+    }
+    if (typeof u.key1?.key2 === 'number') {
+        u;  //Foo1 | Foo3
+    }
+    if (typeof u.key1?.key2 !== 'undefined') {
+        u;  //U1
+    }
+    if (typeof u.key1?.key2 === 'undefined') {
+        u;  //Foo1 | Foo2
+    }
+}
+
+function f2Plus(u: U1) {
+    if (typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number') {
+        u;    //should be never, but this should be a design limit?
+    }
+    if (typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number') {
+        u;    //U1
+    }
+    if (typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined') {
+        u;    //should be never, but this should be a design limit?
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined') {
+        u;    //U1
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined') {
+        u;    //U1
+    }
+}
+
+// root optional chain
+function f3(u: U2) {
+    if (typeof u?.key1 !== 'number') {
+        u;  //U2
+    }
+    if (typeof u?.key1 === 'number') {
+        u;  //never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+        u;  //Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1 === 'undefined') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+}
+
+// multi optional chain
+function f4(u: U2) {
+    if (typeof u?.key1?.key2 !== 'number') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+    if (typeof u?.key1?.key2 === 'number') {
+        u;  //Foo1 | Foo3
+    }
+    if (typeof u?.key1?.key2 !== 'undefined') {
+        u;  //Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1?.key2 === 'undefined') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+}
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptionalBySwitch.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptionalBySwitch.ts
new file mode 100644
index 0000000000000..42439ae11dfba
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typeGuardAccordingToPropertyOptionalBySwitch.ts
@@ -0,0 +1,109 @@
+// @strict: true
+
+
+
+interface Foo1 {
+    key1: {
+        key2: number;
+    } | undefined;
+    f1: number;
+}
+
+interface Foo2 {
+    key1: {
+        key2: string
+    } | undefined;
+    f2: number;
+}
+
+interface Foo3 {
+    key1: {
+        key2: number;
+    };
+    f2: number;
+}
+type U1 = Foo1 | Foo2 | Foo3;
+type U2 = Foo1 | Foo2 | Foo3 | undefined;
+
+
+// unnecessary optional chain
+function f1(u: U1) {
+    if (typeof u?.key1 !== 'number') {
+        u;  // U1
+    }
+    if (typeof u?.key1 === 'number') {
+        u;  // never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+        u;  // U1
+    }
+    if (typeof u?.key1 === 'undefined') {
+        u;  // Foo1 | Foo2
+    }
+}
+
+// non-root optional chain
+function f2(u: U1) {
+    if (typeof u.key1?.key2 !== 'number') {
+        u;  //Foo1 | Foo2
+    }
+    if (typeof u.key1?.key2 === 'number') {
+        u;  //Foo1 | Foo3
+    }
+    if (typeof u.key1?.key2 !== 'undefined') {
+        u;  //U1
+    }
+    if (typeof u.key1?.key2 === 'undefined') {
+        u;  //Foo1 | Foo2
+    }
+}
+
+function f2Plus(u: U1) {
+    if (typeof u.key1?.key2 === 'undefined' && typeof u.key1?.key2 === 'number') {
+        u;    // should be never, but this should be a design limit?
+    }
+    if (typeof u.key1?.key2 === 'undefined' || typeof u.key1?.key2 === 'number') {
+        u;    //U1
+    }
+    if (typeof u.key1?.key2 === 'number' && typeof u.key1?.key2 === 'undefined') {
+        u;    // should be never, but this should be a design limit?
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 === 'undefined') {
+        u;    //U1
+    }
+    if (typeof u.key1?.key2 === 'number' || typeof u.key1?.key2 !== 'undefined') {
+        u;    //U1
+    }
+}
+
+// root optional chain
+function f3(u: U2) {
+    if (typeof u?.key1 !== 'number') {
+        u;  //U2
+    }
+    if (typeof u?.key1 === 'number') {
+        u;  //never
+    }
+    if (typeof u?.key1 !== 'undefined') {
+        u;  //Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1 === 'undefined') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+}
+
+// multi optional chain
+function f4(u: U2) {
+    if (typeof u?.key1?.key2 !== 'number') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+    if (typeof u?.key1?.key2 === 'number') {
+        u;  //Foo1 | Foo3
+    }
+    if (typeof u?.key1?.key2 !== 'undefined') {
+        u;  //Foo1 | Foo2 | Foo3
+    }
+    if (typeof u?.key1?.key2 === 'undefined') {
+        u;  //Foo1 | Foo2 | Undefined
+    }
+}
diff --git a/tests/cases/conformance/types/union/discriminatedUnionTypes2.ts b/tests/cases/conformance/types/union/discriminatedUnionTypes2.ts
index 6ef85b2406a51..b73fdb8f0ab83 100644
--- a/tests/cases/conformance/types/union/discriminatedUnionTypes2.ts
+++ b/tests/cases/conformance/types/union/discriminatedUnionTypes2.ts
@@ -131,7 +131,7 @@ function foo1(x: RuntimeValue & { type: 'number' }) {
         x.value;  // number
     }
     else {
-        x.value;  // number
+        x.value;  // Error, x is never
     }
 }
 
diff --git a/tests/cases/conformance/types/union/discriminatedUnionTypes3.ts b/tests/cases/conformance/types/union/discriminatedUnionTypes3.ts
index a5e51271bc586..27cb072b605d7 100644
--- a/tests/cases/conformance/types/union/discriminatedUnionTypes3.ts
+++ b/tests/cases/conformance/types/union/discriminatedUnionTypes3.ts
@@ -1,5 +1,67 @@
 // @strict: true
 
+type A = { type2: "a", a: number }
+type B = { type2: "b", b: number }
+type C = { type2: "c", b: number | string }
+
+type X = { type1: A, x: string }
+type Y = { type1: B, y: string }
+type Z = { type1: C, z: string }
+type W = { type1: undefined }
+
+function f32(x: X | Y) {
+    switch (x.type1.type2) {
+        case "a":
+            x.x // typeof x is X
+            break;
+        case "b":
+            x.y // typeof x is Y
+            break;
+    }
+}
+
+function f33(x: A | B) {
+    switch (x.type2) {
+        case "a":
+            x // typeof x is X
+            break;
+        case "b":
+            x // typeof x is Y
+            break;
+    }
+}
+
+function f34(x: X | Y) {
+    if (x.type1.type2 === "a") {
+        x.x // typeof x is X
+    } else if (x.type1.type2 === "b") {
+        x.y // typeof x is Y
+    }
+}
+
+function f35(x: X | W) {
+    if (x.type1?.type2 === "a") {
+        x.x
+    }
+}
+
+function f36(x: X | W) {
+    x.type1?.type2 ?? x;
+}
+
+type S = { sub: { type0: X }, s: string }
+type T = { sub: { type0: Y }, t: string }
+
+function f37(s: S | T) {
+    if (s.sub.type0.type1.type2 === "a") {
+        s.s // typeof s is S
+        s.sub.type0.x // type of s.sub.type is X
+        s.sub.type0.type1.a // type of s.sub.type.type is A
+    } else {
+        s.s // type error!
+    }
+}
+
 // Repro from #44435
 
 type Correct = {
@@ -16,4 +78,4 @@ const example: SomeReturnType = {} as SomeReturnType;
 
 if (example.err === undefined) {
 	example.property;  // true
-}
\ No newline at end of file
+}