[clang-tools-extra] [clang-tidy] Fix readability-redundant-parentheses false positive on typeof (PR #223512)
Andre Sun via cfe-commits
cfe-commits at lists.llvm.org
Wed Sep 16 09:00:28 PDT 2026
https://github.com/and2049 updated https://github.com/llvm/llvm-project/pull/223512
>From 3f51e48ad299eab6722e1cc20da4e278b8e97fd5 Mon Sep 17 00:00:00 2001
From: andre sun <andsun9999 at gmail.com>
Date: Mon, 14 Sep 2026 15:52:48 -0400
Subject: [PATCH 1/3] [clang-tidy] Fix readability-redundant-parentheses false
positive on typeof
The required parentheses of typeof/typeof_unqual operands are no longer flagged as redundant. Fixes #220899.
---
.../readability/RedundantParenthesesCheck.cpp | 12 +++++++++++-
clang-tools-extra/docs/ReleaseNotes.md | 4 ++++
.../checkers/readability/redundant-parentheses-c23.c | 10 ++++++++++
.../checkers/readability/redundant-parentheses.cpp | 1 +
4 files changed, 26 insertions(+), 1 deletion(-)
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses-c23.c
diff --git a/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp b/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp
index 8435c438360a5..bbbc42a325da9 100644
--- a/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp
@@ -10,6 +10,7 @@
#include "../utils/Matchers.h"
#include "../utils/OptionsUtils.h"
#include "clang/AST/Expr.h"
+#include "clang/AST/TypeLoc.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/ASTMatchers/ASTMatchersMacros.h"
@@ -33,6 +34,13 @@ AST_MATCHER(ParenExpr, isInMacro) {
E->getBeginLoc().isMacroID() || E->getEndLoc().isMacroID();
}
+AST_MATCHER(ParenExpr, isTypeOfArgument) {
+ return llvm::any_of(Finder->getASTContext().getParents(Node),
+ [](const DynTypedNode &Parent) {
+ return Parent.get<TypeOfExprTypeLoc>() != nullptr;
+ });
+}
+
} // namespace
static FixItHint createSpacedRemoval(SourceLocation Loc,
@@ -79,7 +87,9 @@ void RedundantParenthesesCheck::registerMatchers(MatchFinder *Finder) {
arraySubscriptExpr())),
unless(anyOf(isInMacro(),
// sizeof(...) is common used.
- hasParent(unaryExprOrTypeTraitExpr()))))
+ hasParent(unaryExprOrTypeTraitExpr()),
+ // typeof(...) parentheses are required syntax.
+ isTypeOfArgument())))
.bind("dup"),
this);
}
diff --git a/clang-tools-extra/docs/ReleaseNotes.md b/clang-tools-extra/docs/ReleaseNotes.md
index e865792b05ff5..8c3472265495b 100644
--- a/clang-tools-extra/docs/ReleaseNotes.md
+++ b/clang-tools-extra/docs/ReleaseNotes.md
@@ -256,6 +256,10 @@ infrastructure are described first, followed by tool-specific sections.
exclusively for overload resolution. Added the {option}`IgnoredTypes`
option to allow customizing the set of ignored types.
+- Improved {doc}`readability-redundant-parentheses
+ <clang-tidy/checks/readability/redundant-parentheses>` check by fixing a false
+ positive on the required parentheses of `typeof` and `typeof_unqual` operands.
+
- Improved {doc}`readability-trailing-comma
<clang-tidy/checks/readability/trailing-comma>` check:
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses-c23.c b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses-c23.c
new file mode 100644
index 0000000000000..06be8140c2d32
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses-c23.c
@@ -0,0 +1,10 @@
+// RUN: %check_clang_tidy -std=c23-or-later %s readability-redundant-parentheses %t
+
+void typeofOperand(void) {
+ typeof(1) a;
+ typeof_unqual(1) b;
+ typeof(a) c;
+ typeof((2)) d;
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: redundant parentheses around expression [readability-redundant-parentheses]
+ // CHECK-FIXES: typeof(2) d;
+}
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses.cpp
index bd6799e512087..aa65b897ae6da 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses.cpp
@@ -61,6 +61,7 @@ void exceptions() {
alignof((3));
// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: redundant parentheses around expression [readability-redundant-parentheses]
// CHECK-FIXES: alignof(3);
+ __typeof__(1) t;
}
namespace std {
>From 0eef76635c4eadd6bb3aaafb865e3f125d603c3c Mon Sep 17 00:00:00 2001
From: andre sun <andsun9999 at gmail.com>
Date: Wed, 16 Sep 2026 11:15:32 -0400
Subject: [PATCH 2/3] [clang-tidy] Match typeof operand parent with a TypeLoc
matcher
Replace the explicit parent traversal with a TypeLoc matcher with hasParent.
---
.../clang-tidy/readability/RedundantParenthesesCheck.cpp | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp b/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp
index bbbc42a325da9..6ea0624e6b76f 100644
--- a/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp
@@ -34,11 +34,8 @@ AST_MATCHER(ParenExpr, isInMacro) {
E->getBeginLoc().isMacroID() || E->getEndLoc().isMacroID();
}
-AST_MATCHER(ParenExpr, isTypeOfArgument) {
- return llvm::any_of(Finder->getASTContext().getParents(Node),
- [](const DynTypedNode &Parent) {
- return Parent.get<TypeOfExprTypeLoc>() != nullptr;
- });
+AST_MATCHER(TypeLoc, isTypeOfExprTypeLoc) {
+ return !Node.getAs<TypeOfExprTypeLoc>().isNull();
}
} // namespace
@@ -89,7 +86,7 @@ void RedundantParenthesesCheck::registerMatchers(MatchFinder *Finder) {
// sizeof(...) is common used.
hasParent(unaryExprOrTypeTraitExpr()),
// typeof(...) parentheses are required syntax.
- isTypeOfArgument())))
+ hasParent(typeLoc(isTypeOfExprTypeLoc())))))
.bind("dup"),
this);
}
>From 420dacbe116b450523abcc9202e5960e73a4c323 Mon Sep 17 00:00:00 2001
From: andre sun <andsun9999 at gmail.com>
Date: Wed, 16 Sep 2026 11:51:59 -0400
Subject: [PATCH 3/3] [clang-tidy] Handle qualified typeof operands
Look through the QualifiedTypeLoc wrapper before the kind check.
---
.../clang-tidy/readability/RedundantParenthesesCheck.cpp | 2 +-
.../checkers/readability/redundant-parentheses-c23.c | 6 ++++++
.../checkers/readability/redundant-parentheses.cpp | 1 +
3 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp b/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp
index 6ea0624e6b76f..bc1d10586da8a 100644
--- a/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/RedundantParenthesesCheck.cpp
@@ -35,7 +35,7 @@ AST_MATCHER(ParenExpr, isInMacro) {
}
AST_MATCHER(TypeLoc, isTypeOfExprTypeLoc) {
- return !Node.getAs<TypeOfExprTypeLoc>().isNull();
+ return !Node.getUnqualifiedLoc().getAs<TypeOfExprTypeLoc>().isNull();
}
} // namespace
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses-c23.c b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses-c23.c
index 06be8140c2d32..024b1bd6ae96c 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses-c23.c
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses-c23.c
@@ -7,4 +7,10 @@ void typeofOperand(void) {
typeof((2)) d;
// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: redundant parentheses around expression [readability-redundant-parentheses]
// CHECK-FIXES: typeof(2) d;
+ const typeof(a) e = a;
+ volatile typeof_unqual(1) f;
+ typeof(a) const g = a;
+ const typeof((3)) h = 3;
+ // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: redundant parentheses around expression [readability-redundant-parentheses]
+ // CHECK-FIXES: const typeof(3) h = 3;
}
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses.cpp
index aa65b897ae6da..c6275be9f2498 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-parentheses.cpp
@@ -62,6 +62,7 @@ void exceptions() {
// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: redundant parentheses around expression [readability-redundant-parentheses]
// CHECK-FIXES: alignof(3);
__typeof__(1) t;
+ const __typeof__(1) ct = 1;
}
namespace std {
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