Rollup merge of #122776 - GuillaumeGomez:rename-hir-let, r=oli-obk

Rename `hir::Let` into `hir::LetExpr`

As discussed on [zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Improve.20naming.20of.20.60ExprKind.3A.3ALet.60.3F).

r? `````@Zalathar`````

8 files changed, 16 insertions, 12 deletions

diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 41f7418ddde..d802dbbcb9e 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -157,7 +157,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     hir::ExprKind::AddrOf(*k, *m, ohs)
                 }
                 ExprKind::Let(pat, scrutinee, span, is_recovered) => {
-                    hir::ExprKind::Let(self.arena.alloc(hir::Let {
+                    hir::ExprKind::Let(self.arena.alloc(hir::LetExpr {
                         span: self.lower_span(*span),
                         pat: self.lower_pat(pat),
                         ty: None,
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index ca5d2930e82..d0446785e4e 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -1259,7 +1259,7 @@ pub struct Arm<'hir> {
 /// In an `if let`, imagine it as `if (let <pat> = <expr>) { ... }`; in a let-else, it is part of
 /// the desugaring to if-let. Only let-else supports the type annotation at present.
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
-pub struct Let<'hir> {
+pub struct LetExpr<'hir> {
     pub span: Span,
     pub pat: &'hir Pat<'hir>,
     pub ty: Option<&'hir Ty<'hir>>,
@@ -1852,7 +1852,7 @@ pub enum ExprKind<'hir> {
     ///
     /// These are not `Local` and only occur as expressions.
     /// The `let Some(x) = foo()` in `if let Some(x) = foo()` is an example of `Let(..)`.
-    Let(&'hir Let<'hir>),
+    Let(&'hir LetExpr<'hir>),
     /// An `if` block, with an optional else block.
     ///
     /// I.e., `if <expr> { <expr> } else { <expr> }`.
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index 186bb234a45..3cf1093eeec 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -753,7 +753,7 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
         ExprKind::DropTemps(ref subexpression) => {
             try_visit!(visitor.visit_expr(subexpression));
         }
-        ExprKind::Let(Let { span: _, pat, ty, init, is_recovered: _ }) => {
+        ExprKind::Let(LetExpr { span: _, pat, ty, init, is_recovered: _ }) => {
             // match the visit order in walk_local
             try_visit!(visitor.visit_expr(init));
             try_visit!(visitor.visit_pat(pat));
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
index 34c24583947..c7651cf3264 100644
--- a/compiler/rustc_hir_pretty/src/lib.rs
+++ b/compiler/rustc_hir_pretty/src/lib.rs
@@ -1387,7 +1387,7 @@ impl<'a> State<'a> {
                 // Print `}`:
                 self.bclose_maybe_open(expr.span, true);
             }
-            hir::ExprKind::Let(&hir::Let { pat, ty, init, .. }) => {
+            hir::ExprKind::Let(&hir::LetExpr { pat, ty, init, .. }) => {
                 self.print_let(pat, ty, init);
             }
             hir::ExprKind::If(test, blk, elseopt) => {
diff --git a/compiler/rustc_hir_typeck/src/_match.rs b/compiler/rustc_hir_typeck/src/_match.rs
index 4b3359858f1..b6421a10e13 100644
--- a/compiler/rustc_hir_typeck/src/_match.rs
+++ b/compiler/rustc_hir_typeck/src/_match.rs
@@ -317,7 +317,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         err.note("`if` expressions without `else` evaluate to `()`");
         err.help("consider adding an `else` block that evaluates to the expected type");
         *error = true;
-        if let ExprKind::Let(hir::Let { span, pat, init, .. }) = cond_expr.kind
+        if let ExprKind::Let(hir::LetExpr { span, pat, init, .. }) = cond_expr.kind
             && let ExprKind::Block(block, _) = then_expr.kind
             // Refutability checks occur on the MIR, so we approximate it here by checking
             // if we have an enum with a single variant or a struct in the pattern.
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 1a142f27809..4c01c201ad2 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -1261,7 +1261,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    pub(super) fn check_expr_let(&self, let_expr: &'tcx hir::Let<'tcx>, hir_id: HirId) -> Ty<'tcx> {
+    pub(super) fn check_expr_let(
+        &self,
+        let_expr: &'tcx hir::LetExpr<'tcx>,
+        hir_id: HirId,
+    ) -> Ty<'tcx> {
         // for let statements, this is done in check_stmt
         let init = let_expr.init;
         self.warn_if_unreachable(init.hir_id, init.span, "block in `let` expression");
diff --git a/compiler/rustc_hir_typeck/src/expr_use_visitor.rs b/compiler/rustc_hir_typeck/src/expr_use_visitor.rs
index 43e95544594..2dc355b72f6 100644
--- a/compiler/rustc_hir_typeck/src/expr_use_visitor.rs
+++ b/compiler/rustc_hir_typeck/src/expr_use_visitor.rs
@@ -245,7 +245,7 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
                 }
             }
 
-            hir::ExprKind::Let(hir::Let { pat, init, .. }) => {
+            hir::ExprKind::Let(hir::LetExpr { pat, init, .. }) => {
                 self.walk_local(init, pat, None, |t| t.borrow_expr(init, ty::ImmBorrow))
             }
 
diff --git a/compiler/rustc_hir_typeck/src/gather_locals.rs b/compiler/rustc_hir_typeck/src/gather_locals.rs
index 4d37f725c94..6dae1fab6dc 100644
--- a/compiler/rustc_hir_typeck/src/gather_locals.rs
+++ b/compiler/rustc_hir_typeck/src/gather_locals.rs
@@ -29,7 +29,7 @@ impl<'a> DeclOrigin<'a> {
     }
 }
 
-/// A declaration is an abstraction of [hir::Local] and [hir::Let].
+/// A declaration is an abstraction of [hir::Local] and [hir::LetExpr].
 ///
 /// It must have a hir_id, as this is how we connect gather_locals to the check functions.
 pub(super) struct Declaration<'a> {
@@ -48,9 +48,9 @@ impl<'a> From<&'a hir::Local<'a>> for Declaration<'a> {
     }
 }
 
-impl<'a> From<(&'a hir::Let<'a>, hir::HirId)> for Declaration<'a> {
-    fn from((let_expr, hir_id): (&'a hir::Let<'a>, hir::HirId)) -> Self {
-        let hir::Let { pat, ty, span, init, is_recovered: _ } = *let_expr;
+impl<'a> From<(&'a hir::LetExpr<'a>, hir::HirId)> for Declaration<'a> {
+    fn from((let_expr, hir_id): (&'a hir::LetExpr<'a>, hir::HirId)) -> Self {
+        let hir::LetExpr { pat, ty, span, init, is_recovered: _ } = *let_expr;
         Declaration { hir_id, pat, ty, span, init: Some(init), origin: DeclOrigin::LetExpr }
     }
 }