Allow trailing params of undefined/unknown/any' to be optional in JS

src/compiler/checker.ts

@@ -25720,6 +25720,10 @@ namespace ts {
             return !!(t.flags & TypeFlags.Void);
         }
 
+        function acceptsVoidUndefinedUnknownOrAny(t: Type): boolean {
+            return !!(t.flags & (TypeFlags.Void | TypeFlags.Undefined | TypeFlags.Unknown | TypeFlags.Any));
+        }
+
         function hasCorrectArity(node: CallLikeExpression, args: readonly Expression[], signature: Signature, signatureHelpTrailingComma = false) {
             let argCount: number;
             let callIsIncomplete = false; // In incomplete call we want to be lenient when we have too few arguments
@@ -25785,7 +25789,7 @@ namespace ts {
             }
             for (let i = argCount; i < effectiveMinimumArguments; i++) {
                 const type = getTypeAtPosition(signature, i);
-                if (filterType(type, acceptsVoid).flags & TypeFlags.Never) {
+                if (filterType(type, isInJSFile(node) && !strictNullChecks ? acceptsVoidUndefinedUnknownOrAny : acceptsVoid).flags & TypeFlags.Never) {
                     return false;
                 }
             }

tests/baselines/reference/callWithMissingVoidUndefinedUnknownAnyInJs(strict=false).errors.txt

@@ -0,0 +1,66 @@
+tests/cases/conformance/expressions/functionCalls/tsfile.ts(6,1): error TS2554: Expected 1 arguments, but got 0.
+tests/cases/conformance/expressions/functionCalls/tsfile.ts(7,1): error TS2554: Expected 1 arguments, but got 0.
+tests/cases/conformance/expressions/functionCalls/tsfile.ts(8,1): error TS2554: Expected 1 arguments, but got 0.
+tests/cases/conformance/expressions/functionCalls/tsfile.ts(10,4): error TS2554: Expected 1 arguments, but got 0.
+tests/cases/conformance/expressions/functionCalls/tsfile.ts(11,4): error TS2554: Expected 1 arguments, but got 0.
+tests/cases/conformance/expressions/functionCalls/tsfile.ts(12,4): error TS2554: Expected 1 arguments, but got 0.
+
+
+==== tests/cases/conformance/expressions/functionCalls/defs.d.ts (0 errors) ====
+    declare function f1(p: void): void;
+    declare function f2(p: undefined): void;
+    declare function f3(p: unknown): void;
+    declare function f4(p: any): void;
+
+    interface I<T> { m(p: T): void; }
+    declare const o1: I<void>;
+    declare const o2: I<undefined>;
+    declare const o3: I<unknown>;
+    declare const o4: I<any>;
+
+==== tests/cases/conformance/expressions/functionCalls/jsfile.js (0 errors) ====
+    // current behavior: treat trailing `void` as optional
+    f1();
+    o1.m();
+
+    // new behavior: treat 'undefined', 'unknown', and 'any' as optional in non-strict mode
+    f2();
+    f3();
+    f4();
+
+    o2.m();
+    o3.m();
+    o4.m();
+
+==== tests/cases/conformance/expressions/functionCalls/tsfile.ts (6 errors) ====
+    // current behavior: treat trailing `void` as optional
+    f1();
+    o1.m();
+
+    // no change in behavior
+    f2();
+    ~~~~
+!!! error TS2554: Expected 1 arguments, but got 0.
+!!! related TS6210 tests/cases/conformance/expressions/functionCalls/defs.d.ts:2:21: An argument for 'p' was not provided.
+    f3();
+    ~~~~
+!!! error TS2554: Expected 1 arguments, but got 0.
+!!! related TS6210 tests/cases/conformance/expressions/functionCalls/defs.d.ts:3:21: An argument for 'p' was not provided.
+    f4();
+    ~~~~
+!!! error TS2554: Expected 1 arguments, but got 0.
+!!! related TS6210 tests/cases/conformance/expressions/functionCalls/defs.d.ts:4:21: An argument for 'p' was not provided.
+
+    o2.m();
+       ~~~
+!!! error TS2554: Expected 1 arguments, but got 0.
+!!! related TS6210 tests/cases/conformance/expressions/functionCalls/defs.d.ts:6:20: An argument for 'p' was not provided.
+    o3.m();
+       ~~~
+!!! error TS2554: Expected 1 arguments, but got 0.
+!!! related TS6210 tests/cases/conformance/expressions/functionCalls/defs.d.ts:6:20: An argument for 'p' was not provided.
+    o4.m();
+       ~~~
+!!! error TS2554: Expected 1 arguments, but got 0.
+!!! related TS6210 tests/cases/conformance/expressions/functionCalls/defs.d.ts:6:20: An argument for 'p' was not provided.
+

tests/baselines/reference/callWithMissingVoidUndefinedUnknownAnyInJs(strict=false).symbols

@@ -0,0 +1,110 @@
+=== tests/cases/conformance/expressions/functionCalls/defs.d.ts ===
+declare function f1(p: void): void;
+>f1 : Symbol(f1, Decl(defs.d.ts, 0, 0))
+>p : Symbol(p, Decl(defs.d.ts, 0, 20))
+
+declare function f2(p: undefined): void;
+>f2 : Symbol(f2, Decl(defs.d.ts, 0, 35))
+>p : Symbol(p, Decl(defs.d.ts, 1, 20))
+
+declare function f3(p: unknown): void;
+>f3 : Symbol(f3, Decl(defs.d.ts, 1, 40))
+>p : Symbol(p, Decl(defs.d.ts, 2, 20))
+
+declare function f4(p: any): void;
+>f4 : Symbol(f4, Decl(defs.d.ts, 2, 38))
+>p : Symbol(p, Decl(defs.d.ts, 3, 20))
+
+interface I<T> { m(p: T): void; }
+>I : Symbol(I, Decl(defs.d.ts, 3, 34))
+>T : Symbol(T, Decl(defs.d.ts, 5, 12))
+>m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+>p : Symbol(p, Decl(defs.d.ts, 5, 19))
+>T : Symbol(T, Decl(defs.d.ts, 5, 12))
+
+declare const o1: I<void>;
+>o1 : Symbol(o1, Decl(defs.d.ts, 6, 13))
+>I : Symbol(I, Decl(defs.d.ts, 3, 34))
+
+declare const o2: I<undefined>;
+>o2 : Symbol(o2, Decl(defs.d.ts, 7, 13))
+>I : Symbol(I, Decl(defs.d.ts, 3, 34))
+
+declare const o3: I<unknown>;
+>o3 : Symbol(o3, Decl(defs.d.ts, 8, 13))
+>I : Symbol(I, Decl(defs.d.ts, 3, 34))
+
+declare const o4: I<any>;
+>o4 : Symbol(o4, Decl(defs.d.ts, 9, 13))
+>I : Symbol(I, Decl(defs.d.ts, 3, 34))
+
+=== tests/cases/conformance/expressions/functionCalls/jsfile.js ===
+// current behavior: treat trailing `void` as optional
+f1();
+>f1 : Symbol(f1, Decl(defs.d.ts, 0, 0))
+
+o1.m();
+>o1.m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+>o1 : Symbol(o1, Decl(defs.d.ts, 6, 13))
+>m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+
+// new behavior: treat 'undefined', 'unknown', and 'any' as optional in non-strict mode
+f2();
+>f2 : Symbol(f2, Decl(defs.d.ts, 0, 35))
+
+f3();
+>f3 : Symbol(f3, Decl(defs.d.ts, 1, 40))
+
+f4();
+>f4 : Symbol(f4, Decl(defs.d.ts, 2, 38))
+
+o2.m();
+>o2.m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+>o2 : Symbol(o2, Decl(defs.d.ts, 7, 13))
+>m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+
+o3.m();
+>o3.m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+>o3 : Symbol(o3, Decl(defs.d.ts, 8, 13))
+>m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+
+o4.m();
+>o4.m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+>o4 : Symbol(o4, Decl(defs.d.ts, 9, 13))
+>m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+
+=== tests/cases/conformance/expressions/functionCalls/tsfile.ts ===
+// current behavior: treat trailing `void` as optional
+f1();
+>f1 : Symbol(f1, Decl(defs.d.ts, 0, 0))
+
+o1.m();
+>o1.m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+>o1 : Symbol(o1, Decl(defs.d.ts, 6, 13))
+>m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+
+// no change in behavior
+f2();
+>f2 : Symbol(f2, Decl(defs.d.ts, 0, 35))
+
+f3();
+>f3 : Symbol(f3, Decl(defs.d.ts, 1, 40))
+
+f4();
+>f4 : Symbol(f4, Decl(defs.d.ts, 2, 38))
+
+o2.m();
+>o2.m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+>o2 : Symbol(o2, Decl(defs.d.ts, 7, 13))
+>m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+
+o3.m();
+>o3.m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+>o3 : Symbol(o3, Decl(defs.d.ts, 8, 13))
+>m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+
+o4.m();
+>o4.m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+>o4 : Symbol(o4, Decl(defs.d.ts, 9, 13))
+>m : Symbol(I.m, Decl(defs.d.ts, 5, 16))
+

tests/baselines/reference/callWithMissingVoidUndefinedUnknownAnyInJs(strict=false).types

@@ -0,0 +1,119 @@
+=== tests/cases/conformance/expressions/functionCalls/defs.d.ts ===
+declare function f1(p: void): void;
+>f1 : (p: void) => void
+>p : void
+
+declare function f2(p: undefined): void;
+>f2 : (p: undefined) => void
+>p : undefined
+
+declare function f3(p: unknown): void;
+>f3 : (p: unknown) => void
+>p : unknown
+
+declare function f4(p: any): void;
+>f4 : (p: any) => void
+>p : any
+
+interface I<T> { m(p: T): void; }
+>m : (p: T) => void
+>p : T
+
+declare const o1: I<void>;
+>o1 : I<void>
+
+declare const o2: I<undefined>;
+>o2 : I<undefined>
+
+declare const o3: I<unknown>;
+>o3 : I<unknown>
+
+declare const o4: I<any>;
+>o4 : I<any>
+
+=== tests/cases/conformance/expressions/functionCalls/jsfile.js ===
+// current behavior: treat trailing `void` as optional
+f1();
+>f1() : void
+>f1 : (p: void) => void
+
+o1.m();
+>o1.m() : void
+>o1.m : (p: void) => void
+>o1 : I<void>
+>m : (p: void) => void
+
+// new behavior: treat 'undefined', 'unknown', and 'any' as optional in non-strict mode
+f2();
+>f2() : void
+>f2 : (p: undefined) => void
+
+f3();
+>f3() : void
+>f3 : (p: unknown) => void
+
+f4();
+>f4() : void
+>f4 : (p: any) => void
+
+o2.m();
+>o2.m() : void
+>o2.m : (p: undefined) => void
+>o2 : I<undefined>
+>m : (p: undefined) => void
+
+o3.m();
+>o3.m() : void
+>o3.m : (p: unknown) => void
+>o3 : I<unknown>
+>m : (p: unknown) => void
+
+o4.m();
+>o4.m() : void
+>o4.m : (p: any) => void
+>o4 : I<any>
+>m : (p: any) => void
+
+=== tests/cases/conformance/expressions/functionCalls/tsfile.ts ===
+// current behavior: treat trailing `void` as optional
+f1();
+>f1() : void
+>f1 : (p: void) => void
+
+o1.m();
+>o1.m() : void
+>o1.m : (p: void) => void
+>o1 : I<void>
+>m : (p: void) => void
+
+// no change in behavior
+f2();
+>f2() : void
+>f2 : (p: undefined) => void
+
+f3();
+>f3() : void
+>f3 : (p: unknown) => void
+
+f4();
+>f4() : void
+>f4 : (p: any) => void
+
+o2.m();
+>o2.m() : void
+>o2.m : (p: undefined) => void
+>o2 : I<undefined>
+>m : (p: undefined) => void
+
+o3.m();
+>o3.m() : void
+>o3.m : (p: unknown) => void
+>o3 : I<unknown>
+>m : (p: unknown) => void
+
+o4.m();
+>o4.m() : void
+>o4.m : (p: any) => void
+>o4 : I<any>
+>m : (p: any) => void
+