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`````

Author: jhpratt

clippy_lints/src/pattern_type_mismatch.rs

@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use rustc_hir::{intravisit, Body, Expr, ExprKind, FnDecl, Let, LocalSource, Mutability, Pat, PatKind, Stmt, StmtKind};
+use rustc_hir::{intravisit, Body, Expr, ExprKind, FnDecl, LetExpr, LocalSource, Mutability, Pat, PatKind, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
@@ -103,7 +103,7 @@ impl<'tcx> LateLintPass<'tcx> for PatternTypeMismatch {
                 }
             }
         }
-        if let ExprKind::Let(Let { pat, .. }) = expr.kind {
+        if let ExprKind::Let(LetExpr { pat, .. }) = expr.kind {
             apply_lint(cx, pat, DerefPossible::Possible);
         }
     }

clippy_lints/src/shadow.rs

@@ -5,7 +5,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::Res;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::hir_id::ItemLocalId;
-use rustc_hir::{Block, Body, BodyOwnerKind, Expr, ExprKind, HirId, Let, Node, Pat, PatKind, QPath, UnOp};
+use rustc_hir::{Block, Body, BodyOwnerKind, Expr, ExprKind, HirId, LetExpr, Node, Pat, PatKind, QPath, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::impl_lint_pass;
 use rustc_span::{Span, Symbol};
@@ -238,7 +238,7 @@ fn find_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'
         let init = match node {
             Node::Arm(_) | Node::Pat(_) => continue,
             Node::Expr(expr) => match expr.kind {
-                ExprKind::Match(e, _, _) | ExprKind::Let(&Let { init: e, .. }) => Some(e),
+                ExprKind::Match(e, _, _) | ExprKind::Let(&LetExpr { init: e, .. }) => Some(e),
                 _ => None,
             },
             Node::Local(local) => local.init,

clippy_lints/src/unused_io_amount.rs

@@ -131,7 +131,7 @@ fn non_consuming_ok_arm<'a>(cx: &LateContext<'a>, arm: &hir::Arm<'a>) -> bool {
 fn check_expr<'a>(cx: &LateContext<'a>, expr: &'a hir::Expr<'a>) {
     match expr.kind {
         hir::ExprKind::If(cond, _, _)
-            if let ExprKind::Let(hir::Let { pat, init, .. }) = cond.kind
+            if let ExprKind::Let(hir::LetExpr { pat, init, .. }) = cond.kind
                 && is_ok_wild_or_dotdot_pattern(cx, pat)
                 && let Some(op) = should_lint(cx, init) =>
         {

clippy_utils/src/higher.rs

@@ -102,7 +102,7 @@ impl<'hir> IfLet<'hir> {
         if let ExprKind::If(
             Expr {
                 kind:
-                    ExprKind::Let(&hir::Let {
+                    ExprKind::Let(&hir::LetExpr {
                         pat: let_pat,
                         init: let_expr,
                         span: let_span,
@@ -379,7 +379,7 @@ impl<'hir> WhileLet<'hir> {
                             ExprKind::If(
                                 Expr {
                                     kind:
-                                        ExprKind::Let(&hir::Let {
+                                        ExprKind::Let(&hir::LetExpr {
                                             pat: let_pat,
                                             init: let_expr,
                                             span: let_span,

clippy_utils/src/hir_utils.rs

@@ -8,7 +8,7 @@ use rustc_hir::def::Res;
 use rustc_hir::MatchSource::TryDesugar;
 use rustc_hir::{
     ArrayLen, BinOpKind, BindingAnnotation, Block, BodyId, Closure, Expr, ExprField, ExprKind, FnRetTy, GenericArg,
-    GenericArgs, HirId, HirIdMap, InlineAsmOperand, Let, Lifetime, LifetimeName, Pat, PatField, PatKind, Path,
+    GenericArgs, HirId, HirIdMap, InlineAsmOperand, LetExpr, Lifetime, LifetimeName, Pat, PatField, PatKind, Path,
     PathSegment, PrimTy, QPath, Stmt, StmtKind, Ty, TyKind, TypeBinding,
 };
 use rustc_lexer::{tokenize, TokenKind};
@@ -837,7 +837,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                     }
                 }
             },
-            ExprKind::Let(Let { pat, init, ty, .. }) => {
+            ExprKind::Let(LetExpr { pat, init, ty, .. }) => {
                 self.hash_expr(init);
                 if let Some(ty) = ty {
                     self.hash_ty(ty);

clippy_utils/src/visitors.rs

@@ -5,7 +5,7 @@ use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind, Res};
 use rustc_hir::intravisit::{self, walk_block, walk_expr, Visitor};
 use rustc_hir::{
-    AnonConst, Arm, Block, BlockCheckMode, Body, BodyId, Expr, ExprKind, HirId, ItemId, ItemKind, Let, Pat, QPath,
+    AnonConst, Arm, Block, BlockCheckMode, Body, BodyId, Expr, ExprKind, HirId, ItemId, ItemKind, LetExpr, Pat, QPath,
     Stmt, UnOp, UnsafeSource, Unsafety,
 };
 use rustc_lint::LateContext;
@@ -624,7 +624,7 @@ pub fn for_each_unconsumed_temporary<'tcx, B>(
             | ExprKind::Field(e, _)
             | ExprKind::Unary(UnOp::Deref, e)
             | ExprKind::Match(e, ..)
-            | ExprKind::Let(&Let { init: e, .. }) => {
+            | ExprKind::Let(&LetExpr { init: e, .. }) => {
                 helper(typeck, false, e, f)?;
             },
             ExprKind::Block(&Block { expr: Some(e), .. }, _) | ExprKind::Cast(e, _) | ExprKind::Unary(_, e) => {