Auto merge of #142398 - fee1-dead-contrib:push-ynxrtswtkyxw, r=oli-obk

early linting: avoid redundant calls to `check_id`

An attempt to address the regression at https://github.com/rust-lang/rust/pull/142240#issuecomment-2964425460

r? `@oli-obk`

cc `@nnethercote` who might have a better understanding of the performance implications

compiler/rustc_ast/src/visit.rs

@@ -1700,7 +1700,8 @@ fn visit_nested_use_tree<'a, V: Visitor<'a>>(
 }
 
 pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) -> V::Result {
-    let Stmt { id: _, kind, span: _ } = statement;
+    let Stmt { id, kind, span: _ } = statement;
+    try_visit!(visit_id(visitor, id));
     match kind {
         StmtKind::Let(local) => try_visit!(visitor.visit_local(local)),
         StmtKind::Item(item) => try_visit!(visitor.visit_item(item)),

compiler/rustc_lint/src/early.rs

@@ -33,10 +33,8 @@ pub struct EarlyContextAndPass<'ecx, 'tcx, T: EarlyLintPass> {
 }
 
 impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
-    // This always-inlined function is for the hot call site.
-    #[inline(always)]
     #[allow(rustc::diagnostic_outside_of_impl)]
-    fn inlined_check_id(&mut self, id: ast::NodeId) {
+    fn check_id(&mut self, id: ast::NodeId) {
         for early_lint in self.context.buffered.take(id) {
             let BufferedEarlyLint { span, node_id: _, lint_id, diagnostic } = early_lint;
             self.context.opt_span_lint(lint_id.lint, span, |diag| {
@@ -45,11 +43,6 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
         }
     }
 
-    // This non-inlined function is for the cold call sites.
-    fn check_id(&mut self, id: ast::NodeId) {
-        self.inlined_check_id(id)
-    }
-
     /// Merge the lints specified by any lint attributes into the
     /// current lint context, call the provided function, then reset the
     /// lints in effect to their previous state.
@@ -61,7 +54,6 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
         debug!(?id);
         let push = self.context.builder.push(attrs, is_crate_node, None);
 
-        self.inlined_check_id(id);
         debug!("early context: enter_attrs({:?})", attrs);
         lint_callback!(self, check_attributes, attrs);
         ensure_sufficient_stack(|| f(self));
@@ -136,12 +128,8 @@ impl<'ast, 'ecx, 'tcx, T: EarlyLintPass> ast_visit::Visitor<'ast>
         // the AST struct that they wrap (e.g. an item)
         self.with_lint_attrs(s.id, s.attrs(), |cx| {
             lint_callback!(cx, check_stmt, s);
+            ast_visit::walk_stmt(cx, s);
         });
-        // The visitor for the AST struct wrapped
-        // by the statement (e.g. `Item`) will call
-        // `with_lint_attrs`, so do this walk
-        // outside of the above `with_lint_attrs` call
-        ast_visit::walk_stmt(self, s);
     }
 
     fn visit_fn(&mut self, fk: ast_visit::FnKind<'ast>, span: Span, id: ast::NodeId) {

tests/ui/label/label_misspelled.stderr

@@ -78,6 +78,14 @@ LL |         break for_loop;
    |               not found in this scope
    |               help: use the similarly named label: `'for_loop`
 
+warning: denote infinite loops with `loop { ... }`
+  --> $DIR/label_misspelled.rs:4:5
+   |
+LL |     'while_loop: while true {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^ help: use `loop`
+   |
+   = note: `#[warn(while_true)]` on by default
+
 warning: unused label
   --> $DIR/label_misspelled.rs:4:5
    |
@@ -90,14 +98,6 @@ note: the lint level is defined here
 LL | #![warn(unused_labels)]
    |         ^^^^^^^^^^^^^
 
-warning: denote infinite loops with `loop { ... }`
-  --> $DIR/label_misspelled.rs:4:5
-   |
-LL |     'while_loop: while true {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^ help: use `loop`
-   |
-   = note: `#[warn(while_true)]` on by default
-
 warning: unused label
   --> $DIR/label_misspelled.rs:9:5
    |
@@ -122,18 +122,18 @@ warning: denote infinite loops with `loop { ... }`
 LL |     'while_loop: while true {
    |     ^^^^^^^^^^^^^^^^^^^^^^^ help: use `loop`
 
-warning: unused label
-  --> $DIR/label_misspelled.rs:47:5
-   |
-LL |     'while_loop: while true {
-   |     ^^^^^^^^^^^
-
 warning: denote infinite loops with `loop { ... }`
   --> $DIR/label_misspelled.rs:47:5
    |
 LL |     'while_loop: while true {
    |     ^^^^^^^^^^^^^^^^^^^^^^^ help: use `loop`
 
+warning: unused label
+  --> $DIR/label_misspelled.rs:47:5
+   |
+LL |     'while_loop: while true {
+   |     ^^^^^^^^^^^
+
 warning: unused label
   --> $DIR/label_misspelled.rs:52:5
    |