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,
  },
 }