Visit ExprField for lint levels.

Author: cjgillot

compiler/rustc_lint/src/late.rs

@@ -157,6 +157,10 @@ impl<'tcx, T: LateLintPass<'tcx>> hir_visit::Visitor<'tcx> for LateContextAndPas
         hir_visit::walk_pat(self, p);
     }
 
+    fn visit_expr_field(&mut self, field: &'tcx hir::ExprField<'tcx>) {
+        self.with_lint_attrs(field.hir_id, |cx| hir_visit::walk_expr_field(cx, field))
+    }
+
     fn visit_expr(&mut self, e: &'tcx hir::Expr<'tcx>) {
         ensure_sufficient_stack(|| {
             self.with_lint_attrs(e.hir_id, |cx| {

compiler/rustc_lint/src/levels.rs

@@ -333,6 +333,11 @@ impl<'tcx> Visitor<'tcx> for LintLevelsBuilder<'_, LintLevelQueryMap<'tcx>> {
         intravisit::walk_expr(self, e);
     }
 
+    fn visit_expr_field(&mut self, f: &'tcx hir::ExprField<'tcx>) {
+        self.add_id(f.hir_id);
+        intravisit::walk_expr_field(self, f);
+    }
+
     fn visit_field_def(&mut self, s: &'tcx hir::FieldDef<'tcx>) {
         self.add_id(s.hir_id);
         intravisit::walk_field_def(self, s);

tests/ui/lint/expr-field.rs

@@ -0,0 +1,15 @@
+// check-pass
+
+pub struct A {
+    pub x: u32,
+}
+
+#[deny(unused_comparisons)]
+pub fn foo(y: u32) -> A {
+    A {
+        #[allow(unused_comparisons)]
+        x: if y < 0 { 1 } else { 2 },
+    }
+}
+
+fn main() {}