Remove hir::Expr::attrs.

Author: cjgillot

compiler/rustc_ast_lowering/src/expr.rs

@@ -258,10 +258,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         ex.span = e.span;
                     }
                     // Merge attributes into the inner expression.
-                    let mut attrs: Vec<_> = e.attrs.iter().map(|a| self.lower_attr(a)).collect();
-                    attrs.extend::<Vec<_>>(ex.attrs.into());
-                    self.attrs[ex.hir_id] = &*self.arena.alloc_from_iter(attrs.iter().cloned());
-                    ex.attrs = attrs.into();
+                    self.attrs[ex.hir_id] = &*self.arena.alloc_from_iter(
+                        e.attrs
+                            .iter()
+                            .map(|a| self.lower_attr(a))
+                            .chain(self.attrs[ex.hir_id].iter().cloned()),
+                    );
                     return ex;
                 }
 
@@ -274,9 +276,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
             };
 
             let hir_id = self.lower_node_id(e.id);
-            let attrs = e.attrs.iter().map(|a| self.lower_attr(a)).collect::<Vec<_>>();
-            self.attrs.push_sparse(hir_id, &*self.arena.alloc_from_iter(attrs.iter().cloned()));
-            hir::Expr { hir_id, kind, span: e.span, attrs: attrs.into() }
+            self.lower_attrs(hir_id, &e.attrs);
+            hir::Expr { hir_id, kind, span: e.span }
         })
     }
 
@@ -684,12 +685,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
             span,
             Some(hir::Movability::Static),
         );
-        let generator = hir::Expr {
-            hir_id: self.lower_node_id(closure_node_id),
-            kind: generator_kind,
-            span,
-            attrs: ThinVec::new(),
-        };
+        let generator =
+            hir::Expr { hir_id: self.lower_node_id(closure_node_id), kind: generator_kind, span };
 
         // `future::from_generator`:
         let unstable_span =
@@ -843,7 +840,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
             hir_id: loop_hir_id,
             kind: hir::ExprKind::Loop(loop_block, None, hir::LoopSource::Loop, span),
             span,
-            attrs: ThinVec::new(),
         });
 
         // mut pinned => loop { ... }
@@ -1813,12 +1809,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
             hir::LoopSource::ForLoop,
             e.span.with_hi(orig_head_span.hi()),
         );
-        let loop_expr = self.arena.alloc(hir::Expr {
-            hir_id: self.lower_node_id(e.id),
-            kind,
-            span: e.span,
-            attrs: ThinVec::new(),
-        });
+        let loop_expr =
+            self.arena.alloc(hir::Expr { hir_id: self.lower_node_id(e.id), kind, span: e.span });
 
         // `mut iter => { ... }`
         let iter_arm = self.arm(iter_pat, loop_expr);
@@ -2154,8 +2146,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
         attrs: AttrVec,
     ) -> hir::Expr<'hir> {
         let hir_id = self.next_id();
-        self.attrs.push_sparse(hir_id, &*self.arena.alloc_from_iter(attrs.iter().cloned()));
-        hir::Expr { hir_id, kind, span, attrs }
+        self.lower_attrs(hir_id, &attrs);
+        hir::Expr { hir_id, kind, span }
     }
 
     fn field(&mut self, ident: Ident, expr: &'hir hir::Expr<'hir>, span: Span) -> hir::Field<'hir> {

compiler/rustc_ast_lowering/src/lib.rs

@@ -979,7 +979,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         ret
     }
 
-    fn lower_attr(&mut self, attr: &Attribute) -> Attribute {
+    fn lower_attr(&self, attr: &Attribute) -> Attribute {
         // Note that we explicitly do not walk the path. Since we don't really
         // lower attributes (we use the AST version) there is nowhere to keep
         // the `HirId`s. We don't actually need HIR version of attributes anyway.
@@ -999,7 +999,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         Attribute { kind, id: attr.id, style: attr.style, span: attr.span }
     }
 
-    fn lower_mac_args(&mut self, args: &MacArgs) -> MacArgs {
+    fn lower_mac_args(&self, args: &MacArgs) -> MacArgs {
         match *args {
             MacArgs::Empty => MacArgs::Empty,
             MacArgs::Delimited(dspan, delim, ref tokens) => {

compiler/rustc_hir/src/hir.rs

@@ -6,7 +6,7 @@ use crate::{itemlikevisit, HirIdVec, LangItem};
 
 use rustc_ast::util::parser::ExprPrecedence;
 use rustc_ast::{self as ast, CrateSugar, LlvmAsmDialect};
-use rustc_ast::{AttrVec, Attribute, FloatTy, IntTy, Label, LitKind, StrStyle, UintTy};
+use rustc_ast::{Attribute, FloatTy, IntTy, Label, LitKind, StrStyle, UintTy};
 pub use rustc_ast::{BorrowKind, ImplPolarity, IsAuto};
 pub use rustc_ast::{CaptureBy, Movability, Mutability};
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
@@ -1446,7 +1446,6 @@ pub struct AnonConst {
 pub struct Expr<'hir> {
     pub hir_id: HirId,
     pub kind: ExprKind<'hir>,
-    pub attrs: AttrVec,
     pub span: Span,
 }
 
@@ -3071,7 +3070,7 @@ impl<'hir> Node<'hir> {
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 mod size_asserts {
     rustc_data_structures::static_assert_size!(super::Block<'static>, 48);
-    rustc_data_structures::static_assert_size!(super::Expr<'static>, 72);
+    rustc_data_structures::static_assert_size!(super::Expr<'static>, 64);
     rustc_data_structures::static_assert_size!(super::Pat<'static>, 88);
     rustc_data_structures::static_assert_size!(super::QPath<'static>, 24);
     rustc_data_structures::static_assert_size!(super::Ty<'static>, 72);

compiler/rustc_hir_pretty/src/lib.rs

@@ -1334,7 +1334,7 @@ impl<'a> State<'a> {
 
     pub fn print_expr(&mut self, expr: &hir::Expr<'_>) {
         self.maybe_print_comment(expr.span.lo());
-        self.print_outer_attributes(&expr.attrs);
+        self.print_outer_attributes(self.attrs(expr.hir_id));
         self.ibox(INDENT_UNIT);
         self.ann.pre(self, AnnNode::Expr(expr));
         match expr.kind {

compiler/rustc_middle/src/ich/impls_hir.rs

@@ -66,11 +66,10 @@ impl<'ctx> rustc_hir::HashStableContext for StableHashingContext<'ctx> {
 
     fn hash_hir_expr(&mut self, expr: &hir::Expr<'_>, hasher: &mut StableHasher) {
         self.while_hashing_hir_bodies(true, |hcx| {
-            let hir::Expr { hir_id: _, ref span, ref kind, ref attrs } = *expr;
+            let hir::Expr { hir_id: _, ref span, ref kind } = *expr;
 
             span.hash_stable(hcx, hasher);
             kind.hash_stable(hcx, hasher);
-            attrs.hash_stable(hcx, hasher);
         })
     }
 

src/tools/clippy/clippy_lints/src/returns.rs

@@ -177,7 +177,8 @@ fn check_final_expr<'tcx>(
         // simple return is always "bad"
         ExprKind::Ret(ref inner) => {
             // allow `#[cfg(a)] return a; #[cfg(b)] return b;`
-            if !expr.attrs.iter().any(attr_is_cfg) {
+            let attrs = cx.tcx.hir().attrs(expr.hir_id);
+            if !attrs.iter().any(attr_is_cfg) {
                 let borrows = inner.map_or(false, |inner| last_statement_borrows(cx, inner));
                 if !borrows {
                     emit_return_lint(

src/tools/clippy/clippy_lints/src/utils/inspector.rs

@@ -89,7 +89,7 @@ impl<'tcx> LateLintPass<'tcx> for DeepCodeInspector {
     //
 
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
-        if !has_attr(cx.sess(), &expr.attrs) {
+        if !has_attr(cx.sess(), cx.tcx.hir().attrs(expr.hir_id)) {
             return;
         }
         print_expr(cx, expr, 0);