Perform match checking on THIR.

Author: cjgillot

compiler/rustc_hir/src/pat_util.rs

@@ -2,7 +2,6 @@ use crate::def::{CtorOf, DefKind, Res};
 use crate::def_id::DefId;
 use crate::hir::{self, BindingAnnotation, ByRef, HirId, PatKind};
 use rustc_data_structures::fx::FxHashSet;
-use rustc_span::hygiene::DesugaringKind;
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
 
@@ -136,14 +135,4 @@ impl hir::Pat<'_> {
         });
         result
     }
-
-    /// If the pattern is `Some(<pat>)` from a desugared for loop, returns the inner pattern
-    pub fn for_loop_some(&self) -> Option<&Self> {
-        if self.span.desugaring_kind() == Some(DesugaringKind::ForLoop) {
-            if let hir::PatKind::Struct(_, [pat_field], _) = self.kind {
-                return Some(pat_field.pat);
-            }
-        }
-        None
-    }
 }

compiler/rustc_mir_build/messages.ftl

@@ -239,19 +239,9 @@ mir_build_trailing_irrefutable_let_patterns = trailing irrefutable {$count ->
     } into the body
 
 mir_build_bindings_with_variant_name =
-    pattern binding `{$ident}` is named the same as one of the variants of the type `{$ty_path}`
+    pattern binding `{$name}` is named the same as one of the variants of the type `{$ty_path}`
     .suggestion = to match on the variant, qualify the path
 
-mir_build_irrefutable_let_patterns_generic_let = irrefutable `let` {$count ->
-        [one] pattern
-        *[other] patterns
-    }
-    .note = {$count ->
-        [one] this pattern
-        *[other] these patterns
-    } will always match, so the `let` is useless
-    .help = consider removing `let`
-
 mir_build_irrefutable_let_patterns_if_let = irrefutable `if let` {$count ->
         [one] pattern
         *[other] patterns

compiler/rustc_mir_build/src/build/mod.rs

@@ -58,6 +58,7 @@ fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_
         ty::WithOptConstParam { did, const_param_did: None } => {
             tcx.ensure_with_value().thir_check_unsafety(did);
             tcx.ensure_with_value().thir_abstract_const(did);
+            tcx.ensure_with_value().check_match(did);
         }
     }
 

compiler/rustc_mir_build/src/errors.rs

@@ -10,7 +10,8 @@ use rustc_hir::def::Res;
 use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_middle::thir::Pat;
 use rustc_middle::ty::{self, Ty};
-use rustc_span::{symbol::Ident, Span};
+use rustc_span::symbol::Symbol;
+use rustc_span::Span;
 
 #[derive(LintDiagnostic)]
 #[diag(mir_build_unconditional_recursion)]
@@ -534,18 +535,10 @@ pub struct TrailingIrrefutableLetPatterns {
 #[derive(LintDiagnostic)]
 #[diag(mir_build_bindings_with_variant_name, code = "E0170")]
 pub struct BindingsWithVariantName {
-    #[suggestion(code = "{ty_path}::{ident}", applicability = "machine-applicable")]
+    #[suggestion(code = "{ty_path}::{name}", applicability = "machine-applicable")]
     pub suggestion: Option<Span>,
     pub ty_path: String,
-    pub ident: Ident,
-}
-
-#[derive(LintDiagnostic)]
-#[diag(mir_build_irrefutable_let_patterns_generic_let)]
-#[note]
-#[help]
-pub struct IrrefutableLetPatternsGenericLet {
-    pub count: usize,
+    pub name: Symbol,
 }
 
 #[derive(LintDiagnostic)]
@@ -590,7 +583,7 @@ pub struct BorrowOfMovedValue<'tcx> {
     pub binding_span: Span,
     #[label(mir_build_value_borrowed_label)]
     pub conflicts_ref: Vec<Span>,
-    pub name: Ident,
+    pub name: Symbol,
     pub ty: Ty<'tcx>,
     #[suggestion(code = "ref ", applicability = "machine-applicable")]
     pub suggest_borrowing: Option<Span>,
@@ -638,19 +631,19 @@ pub enum Conflict {
     Mut {
         #[primary_span]
         span: Span,
-        name: Ident,
+        name: Symbol,
     },
     #[label(mir_build_borrow)]
     Ref {
         #[primary_span]
         span: Span,
-        name: Ident,
+        name: Symbol,
     },
     #[label(mir_build_moved)]
     Moved {
         #[primary_span]
         span: Span,
-        name: Ident,
+        name: Symbol,
     },
 }