Rollup merge of rust-lang#122780 - GuillaumeGomez:rename-hir-local, r=oli-obk

Rename `hir::Local` into `hir::LetStmt`

Follow-up of rust-lang#122776.

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

I made this change into a separate PR because I'm less sure about this change as is. For example, we have `visit_local` and `LocalSource` items. Is it fine to keep these two as is (I supposed it is but I prefer to ask) or not? Having `Node::Local(LetStmt)` makes things more explicit but is it going too far?

r? ```@oli-obk```

Author: matthiaskrgr

clippy_lints/src/assigning_clones.rs

@@ -163,7 +163,7 @@ fn is_ok_to_suggest<'tcx>(cx: &LateContext<'tcx>, lhs: &Expr<'tcx>, call: &CallC
         // TODO: This check currently bails if the local variable has no initializer.
         // That is overly conservative - the lint should fire even if there was no initializer,
         // but the variable has been initialized before `lhs` was evaluated.
-        if let Some(Node::Local(local)) = cx.tcx.hir().parent_id_iter(local).next().map(|p| cx.tcx.hir_node(p))
+        if let Some(Node::LetStmt(local)) = cx.tcx.hir().parent_id_iter(local).next().map(|p| cx.tcx.hir_node(p))
             && local.init.is_none()
         {
             return false;

clippy_lints/src/box_default.rs

@@ -6,7 +6,7 @@ use clippy_utils::{is_default_equivalent, path_def_id};
 use rustc_errors::Applicability;
 use rustc_hir::def::Res;
 use rustc_hir::intravisit::{walk_ty, Visitor};
-use rustc_hir::{Block, Expr, ExprKind, Local, Node, QPath, Ty, TyKind};
+use rustc_hir::{Block, Expr, ExprKind, LetStmt, Node, QPath, Ty, TyKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::print::with_forced_trimmed_paths;
@@ -139,7 +139,7 @@ impl<'tcx> Visitor<'tcx> for InferVisitor {
 
 fn given_type(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     match cx.tcx.parent_hir_node(expr.hir_id) {
-        Node::Local(Local { ty: Some(ty), .. }) => {
+        Node::LetStmt(LetStmt { ty: Some(ty), .. }) => {
             let mut v = InferVisitor::default();
             v.visit_ty(ty);
             !v.0

clippy_lints/src/casts/ref_as_ptr.rs

@@ -24,7 +24,7 @@ pub(super) fn check<'tcx>(
         && let ty::RawPtr(_, to_mutbl) = cast_to.kind()
         && let Some(use_cx) = expr_use_ctxt(cx, expr)
         // TODO: only block the lint if `cast_expr` is a temporary
-        && !matches!(use_cx.node, ExprUseNode::Local(_) | ExprUseNode::ConstStatic(_))
+        && !matches!(use_cx.node, ExprUseNode::LetStmt(_) | ExprUseNode::ConstStatic(_))
     {
         let core_or_std = if is_no_std_crate(cx) { "core" } else { "std" };
         let fn_name = match to_mutbl {

clippy_lints/src/casts/unnecessary_cast.rs

@@ -66,7 +66,7 @@ pub(super) fn check<'tcx>(
         && let QPath::Resolved(None, Path { res, .. }) = qpath
         && let Res::Local(hir_id) = res
         && let parent = cx.tcx.parent_hir_node(*hir_id)
-        && let Node::Local(local) = parent
+        && let Node::LetStmt(local) = parent
     {
         if let Some(ty) = local.ty
             && let TyKind::Path(qpath) = ty.kind
@@ -275,7 +275,7 @@ fn is_cast_from_ty_alias<'tcx>(cx: &LateContext<'tcx>, expr: impl Visitable<'tcx
                 }
             // Local usage
             } else if let Res::Local(hir_id) = res
-                && let Node::Local(l) = cx.tcx.parent_hir_node(hir_id)
+                && let Node::LetStmt(l) = cx.tcx.parent_hir_node(hir_id)
             {
                 if let Some(e) = l.init
                     && is_cast_from_ty_alias(cx, e, cast_from)

clippy_lints/src/collection_is_never_read.rs

@@ -3,7 +3,7 @@ use clippy_utils::ty::{is_type_diagnostic_item, is_type_lang_item};
 use clippy_utils::visitors::for_each_expr_with_closures;
 use clippy_utils::{get_enclosing_block, path_to_local_id};
 use core::ops::ControlFlow;
-use rustc_hir::{Block, ExprKind, HirId, LangItem, Local, Node, PatKind};
+use rustc_hir::{Block, ExprKind, HirId, LangItem, LetStmt, Node, PatKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::declare_lint_pass;
 use rustc_span::symbol::sym;
@@ -58,7 +58,7 @@ static COLLECTIONS: [Symbol; 9] = [
 ];
 
 impl<'tcx> LateLintPass<'tcx> for CollectionIsNeverRead {
-    fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx Local<'tcx>) {
+    fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx LetStmt<'tcx>) {
         // Look for local variables whose type is a container. Search surrounding bock for read access.
         if match_acceptable_type(cx, local, &COLLECTIONS)
             && let PatKind::Binding(_, local_id, _, _) = local.pat.kind
@@ -70,7 +70,7 @@ impl<'tcx> LateLintPass<'tcx> for CollectionIsNeverRead {
     }
 }
 
-fn match_acceptable_type(cx: &LateContext<'_>, local: &Local<'_>, collections: &[rustc_span::Symbol]) -> bool {
+fn match_acceptable_type(cx: &LateContext<'_>, local: &LetStmt<'_>, collections: &[rustc_span::Symbol]) -> bool {
     let ty = cx.typeck_results().pat_ty(local.pat);
     collections.iter().any(|&sym| is_type_diagnostic_item(cx, ty, sym))
     // String type is a lang item but not a diagnostic item for now so we need a separate check

clippy_lints/src/ignored_unit_patterns.rs

@@ -46,7 +46,7 @@ impl<'tcx> LateLintPass<'tcx> for IgnoredUnitPatterns {
                 // Ignore function parameters
                 return;
             },
-            Node::Local(local) if local.ty.is_some() => {
+            Node::LetStmt(local) if local.ty.is_some() => {
                 // Ignore let bindings with explicit type
                 return;
             },

clippy_lints/src/let_underscore.rs

@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::ty::{implements_trait, is_must_use_ty, match_type};
 use clippy_utils::{is_from_proc_macro, is_must_use_func_call, paths};
-use rustc_hir::{Local, LocalSource, PatKind};
+use rustc_hir::{LetStmt, LocalSource, PatKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{GenericArgKind, IsSuggestable};
@@ -138,7 +138,7 @@ const SYNC_GUARD_PATHS: [&[&str]; 3] = [
 ];
 
 impl<'tcx> LateLintPass<'tcx> for LetUnderscore {
-    fn check_local(&mut self, cx: &LateContext<'tcx>, local: &Local<'tcx>) {
+    fn check_local(&mut self, cx: &LateContext<'tcx>, local: &LetStmt<'tcx>) {
         if matches!(local.source, LocalSource::Normal)
             && !in_external_macro(cx.tcx.sess, local.span)
             && let PatKind::Wild = local.pat.kind

clippy_lints/src/let_with_type_underscore.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::source::snippet;
-use rustc_hir::{Local, TyKind};
+use rustc_hir::{LetStmt, TyKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
@@ -26,7 +26,7 @@ declare_clippy_lint! {
 declare_lint_pass!(UnderscoreTyped => [LET_WITH_TYPE_UNDERSCORE]);
 
 impl LateLintPass<'_> for UnderscoreTyped {
-    fn check_local(&mut self, cx: &LateContext<'_>, local: &Local<'_>) {
+    fn check_local(&mut self, cx: &LateContext<'_>, local: &LetStmt<'_>) {
         if !in_external_macro(cx.tcx.sess, local.span)
             && let Some(ty) = local.ty // Ensure that it has a type defined
             && let TyKind::Infer = &ty.kind // that type is '_'

clippy_lints/src/loops/same_item_push.rs

@@ -62,7 +62,7 @@ pub(super) fn check<'tcx>(
                         if let Node::Pat(pat) = node
                             && let PatKind::Binding(bind_ann, ..) = pat.kind
                             && !matches!(bind_ann, BindingAnnotation(_, Mutability::Mut))
-                            && let Node::Local(parent_let_expr) = cx.tcx.parent_hir_node(hir_id)
+                            && let Node::LetStmt(parent_let_expr) = cx.tcx.parent_hir_node(hir_id)
                             && let Some(init) = parent_let_expr.init
                         {
                             match init.kind {

clippy_lints/src/loops/utils.rs

@@ -3,7 +3,7 @@ use clippy_utils::{get_parent_expr, is_integer_const, path_to_local, path_to_loc
 use rustc_ast::ast::{LitIntType, LitKind};
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_expr, walk_local, Visitor};
-use rustc_hir::{BinOpKind, BorrowKind, Expr, ExprKind, HirId, HirIdMap, Local, Mutability, PatKind};
+use rustc_hir::{BinOpKind, BorrowKind, Expr, ExprKind, HirId, HirIdMap, LetStmt, Mutability, PatKind};
 use rustc_lint::LateContext;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::{self, Ty};
@@ -141,7 +141,7 @@ impl<'a, 'tcx> InitializeVisitor<'a, 'tcx> {
 impl<'a, 'tcx> Visitor<'tcx> for InitializeVisitor<'a, 'tcx> {
     type NestedFilter = nested_filter::OnlyBodies;
 
-    fn visit_local(&mut self, l: &'tcx Local<'_>) {
+    fn visit_local(&mut self, l: &'tcx LetStmt<'_>) {
         // Look for declarations of the variable
         if l.pat.hir_id == self.var_id
             && let PatKind::Binding(.., ident, _) = l.pat.kind