let-else: add hir::Let and type check it like a hir::Local

unify typeck of hir::Local and hir::Let
remove extraneous pub(crate/super)

2 files changed, 9 insertions, 6 deletions

diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
index b4005ccd1cc..092fe131174 100644
--- a/compiler/rustc_mir_build/src/thir/cx/expr.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -605,9 +605,10 @@ impl<'tcx> Cx<'tcx> {
                 },
                 Err(err) => bug!("invalid loop id for continue: {}", err),
             },
-            hir::ExprKind::Let(ref pat, ref expr, _) => {
-                ExprKind::Let { expr: self.mirror_expr(expr), pat: self.pattern_from_hir(pat) }
-            }
+            hir::ExprKind::Let(let_expr) => ExprKind::Let {
+                expr: self.mirror_expr(let_expr.init),
+                pat: self.pattern_from_hir(let_expr.pat),
+            },
             hir::ExprKind::If(cond, then, else_opt) => ExprKind::If {
                 if_then_scope: region::Scope {
                     id: then.hir_id.local_id,
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index d74c53fae53..7a4fd6ffc4a 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -64,7 +64,9 @@ impl<'tcx> Visitor<'tcx> for MatchVisitor<'_, '_, 'tcx> {
         intravisit::walk_expr(self, ex);
         match &ex.kind {
             hir::ExprKind::Match(scrut, arms, source) => self.check_match(scrut, arms, *source),
-            hir::ExprKind::Let(pat, scrut, span) => self.check_let(pat, scrut, *span),
+            hir::ExprKind::Let(hir::Let { pat, init, span, .. }) => {
+                self.check_let(pat, init, *span)
+            }
             _ => {}
         }
     }
@@ -148,9 +150,9 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
         }
     }
 
-    fn check_let(&mut self, pat: &'tcx hir::Pat<'tcx>, expr: &hir::Expr<'_>, span: Span) {
+    fn check_let(&mut self, pat: &'tcx hir::Pat<'tcx>, scrutinee: &hir::Expr<'_>, span: Span) {
         self.check_patterns(pat, Refutable);
-        let mut cx = self.new_cx(expr.hir_id);
+        let mut cx = self.new_cx(scrutinee.hir_id);
         let tpat = self.lower_pattern(&mut cx, pat, &mut false);
         check_let_reachability(&mut cx, pat.hir_id, tpat, span);
     }