comments feedback

compiler/rustc_lint/src/unused.rs

@@ -1009,7 +1009,8 @@ impl EarlyLintPass for UnusedParens {
     }
 
     fn check_ty(&mut self, cx: &EarlyContext<'_>, ty: &ast::Ty) {
-        if let ast::TyKind::Array(_, len) = &ty.kind {
+        match &ty.kind {
+            ast::TyKind::Array(_, len) => {
                 self.check_unused_delims_expr(
                     cx,
                     &len.value,
@@ -1019,7 +1020,7 @@ impl EarlyLintPass for UnusedParens {
                     None,
                 );
             }
-        if let ast::TyKind::Paren(r) = &ty.kind {
+            ast::TyKind::Paren(r) => {
                 match &r.kind {
                     ast::TyKind::TraitObject(..) => {}
                     ast::TyKind::BareFn(b)
@@ -1034,6 +1035,9 @@ impl EarlyLintPass for UnusedParens {
                         self.emit_unused_delims(cx, ty.span, spans, "type", (false, false));
                     }
                 }
+                self.with_self_ty_parens = false;
+            }
+            _ => {}
         }
     }
 
@@ -1055,7 +1059,7 @@ impl EarlyLintPass for UnusedParens {
     }
 
     fn exit_where_predicate(&mut self, _: &EarlyContext<'_>, _: &ast::WherePredicate) {
-        self.with_self_ty_parens = false;
+        assert!(!self.with_self_ty_parens);
     }
 }
 

tests/ui/lint/unused/issue-105061-should-lint.rs

@@ -6,12 +6,18 @@ struct Inv<'a>(&'a mut &'a ());
 trait Trait<'a> {}
 impl<'b> Trait<'b> for for<'a> fn(Inv<'a>) {}
 
-
 fn with_bound()
 where
     for<'b> (for<'a> fn(Inv<'a>)): Trait<'b>, //~ ERROR unnecessary parentheses around type
 {}
 
+trait Hello<T> {}
+fn with_dyn_bound<T>()
+where
+    (dyn Hello<(for<'b> fn(&'b ()))>): Hello<T> //~ ERROR unnecessary parentheses around type
+{}
+
 fn main() {
     with_bound();
+    with_dyn_bound();
 }

tests/ui/lint/unused/issue-105061-should-lint.stderr

@@ -1,5 +1,5 @@
 error: unnecessary parentheses around type
-  --> $DIR/issue-105061-should-lint.rs:12:13
+  --> $DIR/issue-105061-should-lint.rs:11:13
    |
 LL |     for<'b> (for<'a> fn(Inv<'a>)): Trait<'b>,
    |             ^                   ^
@@ -16,5 +16,17 @@ LL -     for<'b> (for<'a> fn(Inv<'a>)): Trait<'b>,
 LL +     for<'b> for<'a> fn(Inv<'a>): Trait<'b>,
    |
 
-error: aborting due to previous error
+error: unnecessary parentheses around type
+  --> $DIR/issue-105061-should-lint.rs:17:16
+   |
+LL |     (dyn Hello<(for<'b> fn(&'b ()))>): Hello<T>
+   |                ^                  ^
+   |
+help: remove these parentheses
+   |
+LL -     (dyn Hello<(for<'b> fn(&'b ()))>): Hello<T>
+LL +     (dyn Hello<for<'b> fn(&'b ())>): Hello<T>
+   |
+
+error: aborting due to 2 previous errors