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: workingjubilee

compiler/rustc_ast_lowering/src/block.rs

@@ -81,7 +81,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         (self.arena.alloc_from_iter(stmts), expr)
     }
 
-    fn lower_local(&mut self, l: &Local) -> &'hir hir::Local<'hir> {
+    fn lower_local(&mut self, l: &Local) -> &'hir hir::LetStmt<'hir> {
         let ty = l
             .ty
             .as_ref()
@@ -97,7 +97,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let span = self.lower_span(l.span);
         let source = hir::LocalSource::Normal;
         self.lower_attrs(hir_id, &l.attrs);
-        self.arena.alloc(hir::Local { hir_id, ty, pat, init, els, span, source })
+        self.arena.alloc(hir::LetStmt { hir_id, ty, pat, init, els, span, source })
     }
 
     fn lower_block_check_mode(&mut self, b: &BlockCheckMode) -> hir::BlockCheckMode {

compiler/rustc_ast_lowering/src/index.rs

@@ -302,8 +302,8 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         });
     }
 
-    fn visit_local(&mut self, l: &'hir Local<'hir>) {
-        self.insert(l.span, l.hir_id, Node::Local(l));
+    fn visit_local(&mut self, l: &'hir LetStmt<'hir>) {
+        self.insert(l.span, l.hir_id, Node::LetStmt(l));
         self.with_parent(l.hir_id, |this| {
             intravisit::walk_local(this, l);
         })

compiler/rustc_ast_lowering/src/lib.rs

@@ -2341,7 +2341,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             debug_assert!(!a.is_empty());
             self.attrs.insert(hir_id.local_id, a);
         }
-        let local = hir::Local {
+        let local = hir::LetStmt {
             hir_id,
             init,
             pat,

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -622,7 +622,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
                     // FIXME: We make sure that this is a normal top-level binding,
                     // but we could suggest `todo!()` for all uninitalized bindings in the pattern pattern
-                    if let hir::StmtKind::Let(hir::Local { span, ty, init: None, pat, .. }) =
+                    if let hir::StmtKind::Let(hir::LetStmt { span, ty, init: None, pat, .. }) =
                         &ex.kind
                         && let hir::PatKind::Binding(..) = pat.kind
                         && span.contains(self.decl_span)
@@ -800,7 +800,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         for (_, node) in tcx.hir().parent_iter(expr.hir_id) {
             let e = match node {
                 hir::Node::Expr(e) => e,
-                hir::Node::Local(hir::Local { els: Some(els), .. }) => {
+                hir::Node::LetStmt(hir::LetStmt { els: Some(els), .. }) => {
                     let mut finder = BreakFinder { found_breaks: vec![], found_continues: vec![] };
                     finder.visit_block(els);
                     if !finder.found_breaks.is_empty() {
@@ -2124,7 +2124,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 hir::intravisit::walk_expr(self, e);
             }
 
-            fn visit_local(&mut self, local: &'hir hir::Local<'hir>) {
+            fn visit_local(&mut self, local: &'hir hir::LetStmt<'hir>) {
                 if let hir::Pat { kind: hir::PatKind::Binding(_, hir_id, _ident, _), .. } =
                     local.pat
                     && let Some(init) = local.init

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -558,7 +558,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     hir::intravisit::walk_stmt(self, stmt);
                     let expr = match stmt.kind {
                         hir::StmtKind::Semi(expr) | hir::StmtKind::Expr(expr) => expr,
-                        hir::StmtKind::Let(hir::Local { init: Some(expr), .. }) => expr,
+                        hir::StmtKind::Let(hir::LetStmt { init: Some(expr), .. }) => expr,
                         _ => {
                             return;
                         }
@@ -737,7 +737,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             && let body = self.infcx.tcx.hir().body(body_id)
             && let Some(hir_id) = (BindingFinder { span: pat_span }).visit_body(body).break_value()
             && let node = self.infcx.tcx.hir_node(hir_id)
-            && let hir::Node::Local(hir::Local {
+            && let hir::Node::LetStmt(hir::LetStmt {
                 pat: hir::Pat { kind: hir::PatKind::Ref(_, _), .. },
                 ..
             })
@@ -1170,7 +1170,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 };
 
                 if let Some(hir_id) = hir_id
-                    && let hir::Node::Local(local) = self.infcx.tcx.hir_node(hir_id)
+                    && let hir::Node::LetStmt(local) = self.infcx.tcx.hir_node(hir_id)
                 {
                     let tables = self.infcx.tcx.typeck(def_id.as_local().unwrap());
                     if let Some(clone_trait) = self.infcx.tcx.lang_items().clone_trait()

compiler/rustc_hir/src/hir.rs

@@ -1220,7 +1220,7 @@ pub struct Stmt<'hir> {
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub enum StmtKind<'hir> {
     /// A local (`let`) binding.
-    Let(&'hir Local<'hir>),
+    Let(&'hir LetStmt<'hir>),
 
     /// An item binding.
     Item(ItemId),
@@ -1234,7 +1234,7 @@ pub enum StmtKind<'hir> {
 
 /// Represents a `let` statement (i.e., `let <pat>:<ty> = <init>;`).
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
-pub struct Local<'hir> {
+pub struct LetStmt<'hir> {
     pub pat: &'hir Pat<'hir>,
     /// Type annotation, if any (otherwise the type will be inferred).
     pub ty: Option<&'hir Ty<'hir>>,
@@ -1264,7 +1264,7 @@ pub struct Arm<'hir> {
     pub body: &'hir Expr<'hir>,
 }
 
-/// Represents a `let <pat>[: <ty>] = <expr>` expression (not a [`Local`]), occurring in an `if-let`
+/// Represents a `let <pat>[: <ty>] = <expr>` expression (not a [`LetStmt`]), occurring in an `if-let`
 /// or `let-else`, evaluating to a boolean. Typically the pattern is refutable.
 ///
 /// In an `if let`, imagine it as `if (let <pat> = <expr>) { ... }`; in a let-else, it is part of
@@ -1861,7 +1861,7 @@ pub enum ExprKind<'hir> {
     DropTemps(&'hir Expr<'hir>),
     /// A `let $pat = $expr` expression.
     ///
-    /// These are not `Local` and only occur as expressions.
+    /// These are not [`LetStmt`] and only occur as expressions.
     /// The `let Some(x) = foo()` in `if let Some(x) = foo()` is an example of `Let(..)`.
     Let(&'hir LetExpr<'hir>),
     /// An `if` block, with an optional else block.
@@ -3529,7 +3529,7 @@ pub enum Node<'hir> {
     PatField(&'hir PatField<'hir>),
     Arm(&'hir Arm<'hir>),
     Block(&'hir Block<'hir>),
-    Local(&'hir Local<'hir>),
+    LetStmt(&'hir LetStmt<'hir>),
     /// `Ctor` refers to the constructor of an enum variant or struct. Only tuple or unit variants
     /// with synthesized constructors.
     Ctor(&'hir VariantData<'hir>),
@@ -3585,7 +3585,7 @@ impl<'hir> Node<'hir> {
             | Node::Ctor(..)
             | Node::Pat(..)
             | Node::Arm(..)
-            | Node::Local(..)
+            | Node::LetStmt(..)
             | Node::Crate(..)
             | Node::Ty(..)
             | Node::TraitRef(..)
@@ -3757,7 +3757,7 @@ impl<'hir> Node<'hir> {
         expect_pat_field,     &'hir PatField<'hir>,     Node::PatField(n),     n;
         expect_arm,           &'hir Arm<'hir>,          Node::Arm(n),          n;
         expect_block,         &'hir Block<'hir>,        Node::Block(n),        n;
-        expect_local,         &'hir Local<'hir>,        Node::Local(n),        n;
+        expect_let_stmt,      &'hir LetStmt<'hir>,      Node::LetStmt(n),      n;
         expect_ctor,          &'hir VariantData<'hir>,  Node::Ctor(n),         n;
         expect_lifetime,      &'hir Lifetime,           Node::Lifetime(n),     n;
         expect_generic_param, &'hir GenericParam<'hir>, Node::GenericParam(n), n;
@@ -3787,7 +3787,7 @@ mod size_asserts {
     static_assert_size!(ImplItemKind<'_>, 40);
     static_assert_size!(Item<'_>, 88);
     static_assert_size!(ItemKind<'_>, 56);
-    static_assert_size!(Local<'_>, 64);
+    static_assert_size!(LetStmt<'_>, 64);
     static_assert_size!(Param<'_>, 32);
     static_assert_size!(Pat<'_>, 72);
     static_assert_size!(Path<'_>, 40);

compiler/rustc_hir/src/intravisit.rs

@@ -320,7 +320,7 @@ pub trait Visitor<'v>: Sized {
     fn visit_foreign_item(&mut self, i: &'v ForeignItem<'v>) -> Self::Result {
         walk_foreign_item(self, i)
     }
-    fn visit_local(&mut self, l: &'v Local<'v>) -> Self::Result {
+    fn visit_local(&mut self, l: &'v LetStmt<'v>) -> Self::Result {
         walk_local(self, l)
     }
     fn visit_block(&mut self, b: &'v Block<'v>) -> Self::Result {
@@ -606,7 +606,7 @@ pub fn walk_foreign_item<'v, V: Visitor<'v>>(
     V::Result::output()
 }
 
-pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local<'v>) -> V::Result {
+pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v LetStmt<'v>) -> V::Result {
     // Intentionally visiting the expr first - the initialization expr
     // dominates the local's definition.
     visit_opt!(visitor, visit_expr, local.init);

compiler/rustc_hir_analysis/src/check/region.rs

@@ -11,7 +11,7 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{self, Visitor};
-use rustc_hir::{Arm, Block, Expr, Local, Pat, PatKind, Stmt};
+use rustc_hir::{Arm, Block, Expr, LetStmt, Pat, PatKind, Stmt};
 use rustc_index::Idx;
 use rustc_middle::middle::region::*;
 use rustc_middle::ty::TyCtxt;
@@ -123,7 +123,7 @@ fn resolve_block<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, blk: &'tcx h
 
         for (i, statement) in blk.stmts.iter().enumerate() {
             match statement.kind {
-                hir::StmtKind::Let(hir::Local { els: Some(els), .. }) => {
+                hir::StmtKind::Let(LetStmt { els: Some(els), .. }) => {
                     // Let-else has a special lexical structure for variables.
                     // First we take a checkpoint of the current scope context here.
                     let mut prev_cx = visitor.cx;
@@ -855,7 +855,7 @@ impl<'tcx> Visitor<'tcx> for RegionResolutionVisitor<'tcx> {
     fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) {
         resolve_expr(self, ex);
     }
-    fn visit_local(&mut self, l: &'tcx Local<'tcx>) {
+    fn visit_local(&mut self, l: &'tcx LetStmt<'tcx>) {
         resolve_local(self, Some(l.pat), l.init)
     }
 }

compiler/rustc_hir_pretty/src/lib.rs

@@ -113,7 +113,7 @@ impl<'a> State<'a> {
             // `hir_map` to reconstruct their full structure for pretty
             // printing.
             Node::Ctor(..) => panic!("cannot print isolated Ctor"),
-            Node::Local(a) => self.print_local_decl(a),
+            Node::LetStmt(a) => self.print_local_decl(a),
             Node::Crate(..) => panic!("cannot print Crate"),
             Node::WhereBoundPredicate(pred) => {
                 self.print_formal_generic_params(pred.bound_generic_params);
@@ -1544,7 +1544,7 @@ impl<'a> State<'a> {
         self.end()
     }
 
-    fn print_local_decl(&mut self, loc: &hir::Local<'_>) {
+    fn print_local_decl(&mut self, loc: &hir::LetStmt<'_>) {
         self.print_pat(loc.pat);
         if let Some(ty) = loc.ty {
             self.word_space(":");

compiler/rustc_hir_typeck/src/_match.rs

@@ -408,7 +408,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
             }
         }
-        if let hir::Node::Local(hir::Local { ty: Some(_), pat, .. }) = node {
+        if let hir::Node::LetStmt(hir::LetStmt { ty: Some(_), pat, .. }) = node {
             return Some((pat.span, "expected because of this assignment".to_string()));
         }
         None