[clang-tools-extra] [clang-tidy] Add new check 'bugprone-inconsistent-ifelse-braces' (PR #162361)
Davide Cunial via cfe-commits
cfe-commits at lists.llvm.org
Thu Oct 30 12:36:37 PDT 2025
https://github.com/capitan-davide updated https://github.com/llvm/llvm-project/pull/162361
>From 5f61932af5a90b52b5939406a929734dd6353316 Mon Sep 17 00:00:00 2001
From: Davide Cunial <dcunial at proton.me>
Date: Fri, 24 Oct 2025 08:18:09 +0200
Subject: [PATCH 1/6] [clang-tidy] Add new check
'bugprone-inconsistent-ifelse-braces'
---
.../bugprone/BugproneTidyModule.cpp | 3 +
.../clang-tidy/bugprone/CMakeLists.txt | 1 +
.../InconsistentIfelseBracesCheck.cpp | 95 +++++++++++++++
.../bugprone/InconsistentIfelseBracesCheck.h | 41 +++++++
clang-tools-extra/docs/ReleaseNotes.rst | 5 +
.../bugprone/inconsistent-ifelse-braces.rst | 6 +
.../docs/clang-tidy/checks/list.rst | 3 +-
...nconsistent-ifelse-braces-consteval-if.cpp | 28 +++++
.../bugprone/inconsistent-ifelse-braces.cpp | 108 ++++++++++++++++++
9 files changed, 289 insertions(+), 1 deletion(-)
create mode 100644 clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.cpp
create mode 100644 clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
create mode 100644 clang-tools-extra/docs/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.rst
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
diff --git a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
index fe261e729539c..e1e42d22c520e 100644
--- a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
@@ -33,6 +33,7 @@
#include "ImplicitWideningOfMultiplicationResultCheck.h"
#include "InaccurateEraseCheck.h"
#include "IncDecInConditionsCheck.h"
+#include "InconsistentIfelseBracesCheck.h"
#include "IncorrectEnableIfCheck.h"
#include "IncorrectEnableSharedFromThisCheck.h"
#include "IncorrectRoundingsCheck.h"
@@ -150,6 +151,8 @@ class BugproneModule : public ClangTidyModule {
"bugprone-implicit-widening-of-multiplication-result");
CheckFactories.registerCheck<InaccurateEraseCheck>(
"bugprone-inaccurate-erase");
+ CheckFactories.registerCheck<InconsistentIfelseBracesCheck>(
+ "bugprone-inconsistent-ifelse-braces");
CheckFactories.registerCheck<IncorrectEnableIfCheck>(
"bugprone-incorrect-enable-if");
CheckFactories.registerCheck<IncorrectEnableSharedFromThisCheck>(
diff --git a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
index 46bc8efd44bc5..d19fd5017d2e0 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
@@ -28,6 +28,7 @@ add_clang_library(clangTidyBugproneModule STATIC
ForwardingReferenceOverloadCheck.cpp
ImplicitWideningOfMultiplicationResultCheck.cpp
InaccurateEraseCheck.cpp
+ InconsistentIfelseBracesCheck.cpp
IncorrectEnableIfCheck.cpp
IncorrectEnableSharedFromThisCheck.cpp
InvalidEnumDefaultInitializationCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.cpp
new file mode 100644
index 0000000000000..ab3da9f26b390
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.cpp
@@ -0,0 +1,95 @@
+
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "InconsistentIfelseBracesCheck.h"
+#include "../utils/BracesAroundStatement.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+/// Check that at least one branch of the \p If statement is a \c CompoundStmt.
+static bool shouldHaveBraces(const IfStmt *If) {
+ const Stmt *const Then = If->getThen();
+ if (isa<CompoundStmt>(Then))
+ return true;
+
+ if (const Stmt *const Else = If->getElse()) {
+ if (const auto *NestedIf = dyn_cast<const IfStmt>(Else))
+ return shouldHaveBraces(NestedIf);
+
+ return isa<CompoundStmt>(Else);
+ }
+
+ return false;
+}
+
+void InconsistentIfelseBracesCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(
+ traverse(TK_IgnoreUnlessSpelledInSource,
+ ifStmt(hasElse(anything()),
+ unless(isConsteval()), // 'if consteval' always has braces
+ unless(hasParent(ifStmt())))
+ .bind("if_stmt")),
+ this);
+}
+
+void InconsistentIfelseBracesCheck::check(
+ const MatchFinder::MatchResult &Result) {
+ const auto *MatchedIf = Result.Nodes.getNodeAs<IfStmt>("if_stmt");
+ if (!shouldHaveBraces(MatchedIf))
+ return;
+
+ // TODO: Test behavior with macros. This might be the reason why
+ // readability-braces-around-statements defines a findRParenLoc() function
+ // rather than using IfStmt/WhileStmt::getRParenLoc().
+ checkIfStmt(Result, MatchedIf);
+}
+
+void InconsistentIfelseBracesCheck::checkIfStmt(
+ const ast_matchers::MatchFinder::MatchResult &Result, const IfStmt *If) {
+ const Stmt *Then = If->getThen();
+ if (const auto *NestedIf = dyn_cast<const IfStmt>(Then)) {
+ // If the then-branch is a nested IfStmt, first we need to add braces to
+ // it, then we need to check the inner IfStmt.
+ checkStmt(Result, If->getThen(), If->getRParenLoc(), If->getElseLoc());
+ if (shouldHaveBraces(NestedIf))
+ return checkIfStmt(Result, NestedIf);
+ }
+
+ if (!isa<CompoundStmt>(Then))
+ checkStmt(Result, If->getThen(), If->getRParenLoc(), If->getElseLoc());
+
+ if (const Stmt *const Else = If->getElse()) {
+ if (const auto *NestedIf = dyn_cast<const IfStmt>(Else))
+ return checkIfStmt(Result, NestedIf);
+
+ if (!isa<CompoundStmt>(Else))
+ checkStmt(Result, If->getElse(), If->getElseLoc());
+ }
+}
+
+void InconsistentIfelseBracesCheck::checkStmt(
+ const ast_matchers::MatchFinder::MatchResult &Result, const Stmt *S,
+ SourceLocation StartLoc, SourceLocation EndLocHint) {
+ const SourceManager &SM = *Result.SourceManager;
+ const LangOptions &LangOpts = Result.Context->getLangOpts();
+
+ const utils::BraceInsertionHints Hints =
+ utils::getBraceInsertionsHints(S, LangOpts, SM, StartLoc, EndLocHint);
+ if (Hints) {
+ DiagnosticBuilder Diag = diag(Hints.DiagnosticPos, "<message>");
+ if (Hints.offersFixIts()) {
+ Diag << Hints.openingBraceFixIt() << Hints.closingBraceFixIt();
+ }
+ }
+}
+} // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
new file mode 100644
index 0000000000000..b841579223be5
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
@@ -0,0 +1,41 @@
+
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_INCONSISTENTIFELSEBRACESCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_INCONSISTENTIFELSEBRACESCHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang::tidy::bugprone {
+
+/// FIXME: Write a short description.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.html
+class InconsistentIfelseBracesCheck : public ClangTidyCheck {
+public:
+ InconsistentIfelseBracesCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+ bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
+ return LangOpts.CPlusPlus;
+ }
+
+private:
+ void checkIfStmt(const ast_matchers::MatchFinder::MatchResult &Result,
+ const IfStmt *If);
+ void checkStmt(const ast_matchers::MatchFinder::MatchResult &Result,
+ const Stmt *S, SourceLocation StartLoc,
+ SourceLocation EndLocHint = SourceLocation());
+};
+
+} // namespace clang::tidy::bugprone
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_INCONSISTENTIFELSEBRACESCHECK_H
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 7cdff86beeec6..6ed9b93e8c226 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -157,6 +157,11 @@ Improvements to clang-tidy
New checks
^^^^^^^^^^
+- New :doc:`bugprone-inconsistent-ifelse-braces
+ <clang-tidy/checks/bugprone/inconsistent-ifelse-braces>` check.
+
+ FIXME: Write a short description.
+
- New :doc:`bugprone-invalid-enum-default-initialization
<clang-tidy/checks/bugprone/invalid-enum-default-initialization>` check.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.rst
new file mode 100644
index 0000000000000..9592f39d6a13d
--- /dev/null
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.rst
@@ -0,0 +1,6 @@
+.. title:: clang-tidy - bugprone-inconsistent-ifelse-braces
+
+bugprone-inconsistent-ifelse-braces
+===================================
+
+FIXME: Describe what patterns does the check detect and why. Give examples.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index c490d2ece2e0a..9438030c64828 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -101,6 +101,7 @@ Clang-Tidy Checks
:doc:`bugprone-implicit-widening-of-multiplication-result <bugprone/implicit-widening-of-multiplication-result>`, "Yes"
:doc:`bugprone-inaccurate-erase <bugprone/inaccurate-erase>`, "Yes"
:doc:`bugprone-inc-dec-in-conditions <bugprone/inc-dec-in-conditions>`,
+ :doc:`bugprone-inconsistent-ifelse-braces <bugprone/inconsistent-ifelse-braces>`,
:doc:`bugprone-incorrect-enable-if <bugprone/incorrect-enable-if>`, "Yes"
:doc:`bugprone-incorrect-enable-shared-from-this <bugprone/incorrect-enable-shared-from-this>`, "Yes"
:doc:`bugprone-incorrect-roundings <bugprone/incorrect-roundings>`,
@@ -256,7 +257,7 @@ Clang-Tidy Checks
:doc:`llvm-prefer-static-over-anonymous-namespace <llvm/prefer-static-over-anonymous-namespace>`,
:doc:`llvm-twine-local <llvm/twine-local>`, "Yes"
:doc:`llvm-use-new-mlir-op-builder <llvm/use-new-mlir-op-builder>`, "Yes"
- :doc:`llvm-use-ranges <llvm/use-ranges>`, "Yes"
+ :doc:`llvm-use-ranges <llvm/use-ranges>`,
:doc:`llvmlibc-callee-namespace <llvmlibc/callee-namespace>`,
:doc:`llvmlibc-implementation-in-namespace <llvmlibc/implementation-in-namespace>`,
:doc:`llvmlibc-inline-function-decl <llvmlibc/inline-function-decl>`, "Yes"
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp
new file mode 100644
index 0000000000000..c950045dab69f
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp
@@ -0,0 +1,28 @@
+// RUN: %check_clang_tidy -std=c++23-or-later %s bugprone-inconsistent-ifelse-braces %t
+
+bool cond(const char *) { return false; }
+void do_something(const char *) {}
+
+// Positive tests.
+void f() {
+ if consteval {
+ if (cond("if1"))
+ do_something("if-consteval-single-line");
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-4]]:21: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if (cond("if1")) {
+ // CHECK-FIXES: } else {
+ } else {
+ if (cond("if1.1")) {
+ } else
+ do_something("if-consteval-single-line");
+ // CHECK-MESSAGES: :[[@LINE-2]]:11: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else {
+ // CHECK-FIXES: }
+ }
+}
+
+// Negative tests.
+void g() {
+}
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
new file mode 100644
index 0000000000000..de5c79f3f8961
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
@@ -0,0 +1,108 @@
+// RUN: %check_clang_tidy %s bugprone-inconsistent-ifelse-braces %t
+
+bool cond(const char *) { return false; }
+void do_something(const char *) {}
+
+// Positive tests.
+void f() {
+ if (cond("if0") /*comment*/) do_something("if-same-line");
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-3]]:31: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if (cond("if0") /*comment*/) { do_something("if-same-line");
+ // CHECK-FIXES: } else {
+
+ if (cond("if0.1") /*comment*/) {
+ } else do_something("else-same-line");
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else { do_something("else-same-line");
+ // CHECK-FIXES: }
+
+ if (cond("if1"))
+ do_something("if-single-line");
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-4]]:19: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if (cond("if1")) {
+ // CHECK-FIXES: } else {
+
+ if (cond("if1.1")) {
+ } else
+ do_something("else-single-line");
+ // CHECK-MESSAGES: :[[@LINE-2]]:9: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else {
+ // CHECK-FIXES: }
+
+ if (cond("if2") /*comment*/)
+ // some comment
+ do_something("if-multi-line");
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-5]]:31: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if (cond("if2") /*comment*/) {
+ // CHECK-FIXES: } else {
+
+ if (cond("if2.1") /*comment*/) {
+ } else
+ // some comment
+ do_something("else-multi-line");
+ // CHECK-MESSAGES: :[[@LINE-3]]:9: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else {
+ // CHECK-FIXES: }
+
+ if (cond("if3")) do_something("elseif-same-line");
+ else if (cond("if3")) {
+ } else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-4]]:19: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if (cond("if3")) { do_something("elseif-same-line");
+ // CHECK-FIXES: } else if (cond("if3")) {
+
+ if (cond("if3.1")) {
+ } else if (cond("if3.1")) do_something("elseif-same-line");
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-3]]:28: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else if (cond("if3.1")) { do_something("elseif-same-line");
+ // CHECK-FIXES: } else {
+
+ if (cond("if3.2")) {
+ } else if (cond("if3.2")) {
+ } else do_something("elseif-same-line");
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else { do_something("elseif-same-line");
+ // CHECK-FIXES: }
+
+ if (cond("if4-outer"))
+ if (cond("if4-inner"))
+ do_something("nested-if-single-line");
+ else {
+ }
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-7]]:25: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-MESSAGES: :[[@LINE-7]]:27: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if (cond("if4-outer")) {
+ // CHECK-FIXES: if (cond("if4-inner")) {
+ // CHECK-FIXES: } else {
+ // CHECK-FIXES: } else {
+
+ if (cond("if5"))
+ do_something("noelse-single-line");
+ else if (cond("if5")) {
+ }
+ // CHECK-MESSAGES: :[[@LINE-4]]:19: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if (cond("if5")) {
+ // CHECK-FIXES: } else if (cond("if5")) {
+
+ if (cond("if5.1")) {
+ } else if (cond("if5.1"))
+ do_something("noelse-single-line");
+ // CHECK-MESSAGES: :[[@LINE-2]]:28: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else if (cond("if5.1")) {
+ // CHECK-FIXES: }
+}
+
+// Negative tests.
+void g() {
+}
>From 18e6ae847c45e851c886fb7ddbd820f578ede385 Mon Sep 17 00:00:00 2001
From: Davide Cunial <dcunial at proton.me>
Date: Sat, 25 Oct 2025 08:02:52 +0200
Subject: [PATCH 2/6] [clang-tidy] Add some tests to
'bugprone-inconsistent-ifelse-braces'
---
...nconsistent-ifelse-braces-consteval-if.cpp | 33 +++++++++++++++++--
.../bugprone/inconsistent-ifelse-braces.cpp | 27 +++++++++++----
2 files changed, 51 insertions(+), 9 deletions(-)
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp
index c950045dab69f..3eb51c39e2921 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp
@@ -1,22 +1,33 @@
// RUN: %check_clang_tidy -std=c++23-or-later %s bugprone-inconsistent-ifelse-braces %t
bool cond(const char *) { return false; }
+
void do_something(const char *) {}
// Positive tests.
void f() {
if consteval {
if (cond("if1"))
- do_something("if-consteval-single-line");
+ do_something("if-single-line");
else {
}
// CHECK-MESSAGES: :[[@LINE-4]]:21: warning: <message> [bugprone-inconsistent-ifelse-braces]
// CHECK-FIXES: if (cond("if1")) {
// CHECK-FIXES: } else {
+ }
+
+ if consteval {
+ if (cond("if2"))
+ do_something("if-single-line");
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-4]]:21: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if (cond("if2")) {
+ // CHECK-FIXES: } else {
} else {
- if (cond("if1.1")) {
+ if (cond("if2.1")) {
} else
- do_something("if-consteval-single-line");
+ do_something("else-single-line");
// CHECK-MESSAGES: :[[@LINE-2]]:11: warning: <message> [bugprone-inconsistent-ifelse-braces]
// CHECK-FIXES: } else {
// CHECK-FIXES: }
@@ -25,4 +36,20 @@ void f() {
// Negative tests.
void g() {
+ if consteval {
+ if (cond("if0")) {
+ do_something("if-single-line");
+ } else if (cond("if0")) {
+ do_something("elseif-single-line");
+ } else {
+ do_something("else-single-line");
+ }
+ } else {
+ if (cond("if0.1"))
+ do_something("if-single-line");
+ else if (cond("if0.1"))
+ do_something("elseif-single-line");
+ else
+ do_something("else-single-line");
+ }
}
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
index de5c79f3f8961..42a06f475356c 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
@@ -1,6 +1,7 @@
// RUN: %check_clang_tidy %s bugprone-inconsistent-ifelse-braces %t
bool cond(const char *) { return false; }
+
void do_something(const char *) {}
// Positive tests.
@@ -68,14 +69,14 @@ void f() {
if (cond("if3.2")) {
} else if (cond("if3.2")) {
- } else do_something("elseif-same-line");
+ } else do_something("else-same-line");
// CHECK-MESSAGES: :[[@LINE-1]]:9: warning: <message> [bugprone-inconsistent-ifelse-braces]
- // CHECK-FIXES: } else { do_something("elseif-same-line");
+ // CHECK-FIXES: } else { do_something("else-same-line");
// CHECK-FIXES: }
if (cond("if4-outer"))
if (cond("if4-inner"))
- do_something("nested-if-single-line");
+ do_something("if-single-line");
else {
}
else {
@@ -88,7 +89,7 @@ void f() {
// CHECK-FIXES: } else {
if (cond("if5"))
- do_something("noelse-single-line");
+ do_something("if-single-line");
else if (cond("if5")) {
}
// CHECK-MESSAGES: :[[@LINE-4]]:19: warning: <message> [bugprone-inconsistent-ifelse-braces]
@@ -97,7 +98,7 @@ void f() {
if (cond("if5.1")) {
} else if (cond("if5.1"))
- do_something("noelse-single-line");
+ do_something("elseif-single-line");
// CHECK-MESSAGES: :[[@LINE-2]]:28: warning: <message> [bugprone-inconsistent-ifelse-braces]
// CHECK-FIXES: } else if (cond("if5.1")) {
// CHECK-FIXES: }
@@ -105,4 +106,18 @@ void f() {
// Negative tests.
void g() {
-}
+ if (cond("if0")) {
+ do_something("if-single-line");
+ } else if (cond("if0")) {
+ do_something("elseif-single-line");
+ } else {
+ do_something("else-single-line");
+ }
+
+ if (cond("if1"))
+ do_something("if-single-line");
+ else if (cond("if1"))
+ do_something("elseif-single-line");
+ else
+ do_something("else-single-line");
+}
\ No newline at end of file
>From 117eb015fc4deec01c63c7f10acfad5b811e346a Mon Sep 17 00:00:00 2001
From: Davide Cunial <dcunial at proton.me>
Date: Sat, 25 Oct 2025 08:40:34 +0200
Subject: [PATCH 3/6] [clang-tidy] Update documentation for
'bugprone-inconsistent-ifelse-braces'
---
.../InconsistentIfelseBracesCheck.cpp | 18 +++------
.../bugprone/InconsistentIfelseBracesCheck.h | 4 +-
clang-tools-extra/docs/ReleaseNotes.rst | 3 +-
.../bugprone/inconsistent-ifelse-braces.rst | 38 ++++++++++++++++++-
.../docs/clang-tidy/checks/list.rst | 2 +-
.../bugprone/inconsistent-ifelse-braces.cpp | 2 +-
6 files changed, 49 insertions(+), 18 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.cpp
index ab3da9f26b390..0c6b3e3e3ff9c 100644
--- a/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.cpp
@@ -1,4 +1,3 @@
-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
@@ -47,10 +46,6 @@ void InconsistentIfelseBracesCheck::check(
const auto *MatchedIf = Result.Nodes.getNodeAs<IfStmt>("if_stmt");
if (!shouldHaveBraces(MatchedIf))
return;
-
- // TODO: Test behavior with macros. This might be the reason why
- // readability-braces-around-statements defines a findRParenLoc() function
- // rather than using IfStmt/WhileStmt::getRParenLoc().
checkIfStmt(Result, MatchedIf);
}
@@ -62,17 +57,15 @@ void InconsistentIfelseBracesCheck::checkIfStmt(
// it, then we need to check the inner IfStmt.
checkStmt(Result, If->getThen(), If->getRParenLoc(), If->getElseLoc());
if (shouldHaveBraces(NestedIf))
- return checkIfStmt(Result, NestedIf);
- }
-
- if (!isa<CompoundStmt>(Then))
+ checkIfStmt(Result, NestedIf);
+ } else if (!isa<CompoundStmt>(Then)) {
checkStmt(Result, If->getThen(), If->getRParenLoc(), If->getElseLoc());
+ }
if (const Stmt *const Else = If->getElse()) {
if (const auto *NestedIf = dyn_cast<const IfStmt>(Else))
- return checkIfStmt(Result, NestedIf);
-
- if (!isa<CompoundStmt>(Else))
+ checkIfStmt(Result, NestedIf);
+ else if (!isa<CompoundStmt>(Else))
checkStmt(Result, If->getElse(), If->getElseLoc());
}
}
@@ -92,4 +85,5 @@ void InconsistentIfelseBracesCheck::checkStmt(
}
}
}
+
} // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
index b841579223be5..c818f46fea281 100644
--- a/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
@@ -1,4 +1,3 @@
-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
@@ -14,7 +13,8 @@
namespace clang::tidy::bugprone {
-/// FIXME: Write a short description.
+/// Detects `if`/`else` statements where one branch uses braces and the other
+/// does not.
///
/// For the user-facing documentation see:
/// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.html
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 6ed9b93e8c226..28bebceef1006 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -160,7 +160,8 @@ New checks
- New :doc:`bugprone-inconsistent-ifelse-braces
<clang-tidy/checks/bugprone/inconsistent-ifelse-braces>` check.
- FIXME: Write a short description.
+ Detects ``if``/``else`` statements where one branch uses braces and the other
+ does not.
- New :doc:`bugprone-invalid-enum-default-initialization
<clang-tidy/checks/bugprone/invalid-enum-default-initialization>` check.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.rst
index 9592f39d6a13d..44f2d64452393 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.rst
@@ -3,4 +3,40 @@
bugprone-inconsistent-ifelse-braces
===================================
-FIXME: Describe what patterns does the check detect and why. Give examples.
+Detects ``if``/``else`` statements where one branch uses braces and the other
+does not.
+
+Before:
+
+.. code-block:: c++
+
+ if (condition) {
+ statement;
+ } else
+ statement;
+
+ if (condition)
+ statement;
+
+ if (condition)
+ statement;
+ else
+ statement;
+
+After:
+
+.. code-block:: c++
+
+ if (condition) {
+ statement;
+ } else {
+ statement;
+ }
+
+ if (condition)
+ statement;
+
+ if (condition)
+ statement;
+ else
+ statement;
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index 9438030c64828..4c5b70f6c47e5 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -101,7 +101,7 @@ Clang-Tidy Checks
:doc:`bugprone-implicit-widening-of-multiplication-result <bugprone/implicit-widening-of-multiplication-result>`, "Yes"
:doc:`bugprone-inaccurate-erase <bugprone/inaccurate-erase>`, "Yes"
:doc:`bugprone-inc-dec-in-conditions <bugprone/inc-dec-in-conditions>`,
- :doc:`bugprone-inconsistent-ifelse-braces <bugprone/inconsistent-ifelse-braces>`,
+ :doc:`bugprone-inconsistent-ifelse-braces <bugprone/inconsistent-ifelse-braces>`, "Yes"
:doc:`bugprone-incorrect-enable-if <bugprone/incorrect-enable-if>`, "Yes"
:doc:`bugprone-incorrect-enable-shared-from-this <bugprone/incorrect-enable-shared-from-this>`, "Yes"
:doc:`bugprone-incorrect-roundings <bugprone/incorrect-roundings>`,
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
index 42a06f475356c..3d4af258137ce 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
@@ -120,4 +120,4 @@ void g() {
do_something("elseif-single-line");
else
do_something("else-single-line");
-}
\ No newline at end of file
+}
>From 40570f986a7bec192db25c1001294ca8f93d4c75 Mon Sep 17 00:00:00 2001
From: Davide Cunial <dcunial at proton.me>
Date: Mon, 27 Oct 2025 19:10:06 +0100
Subject: [PATCH 4/6] [clang-tidy] Apply suggestions from code review
---
.../clang-tidy/bugprone/InconsistentIfelseBracesCheck.h | 3 ---
1 file changed, 3 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
index c818f46fea281..cfdcfa6923124 100644
--- a/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
@@ -24,9 +24,6 @@ class InconsistentIfelseBracesCheck : public ClangTidyCheck {
: ClangTidyCheck(Name, Context) {}
void registerMatchers(ast_matchers::MatchFinder *Finder) override;
void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
- bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
- return LangOpts.CPlusPlus;
- }
private:
void checkIfStmt(const ast_matchers::MatchFinder::MatchResult &Result,
>From 6a652cd535962254b7bcc3d5acaf0426aa8617bf Mon Sep 17 00:00:00 2001
From: Davide Cunial <dcunial at proton.me>
Date: Tue, 28 Oct 2025 13:11:23 +0100
Subject: [PATCH 5/6] [clang-tidy] Apply suggestions from code review
Co-authored-by: Victor Chernyakin <chernyakin.victor.j at outlook.com>
---
.../clang-tidy/bugprone/InconsistentIfelseBracesCheck.h | 4 ++--
clang-tools-extra/docs/clang-tidy/checks/list.rst | 2 +-
.../checkers/bugprone/inconsistent-ifelse-braces.cpp | 2 +-
3 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
index cfdcfa6923124..a88fa66ffa499 100644
--- a/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/InconsistentIfelseBracesCheck.h
@@ -17,7 +17,7 @@ namespace clang::tidy::bugprone {
/// does not.
///
/// For the user-facing documentation see:
-/// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.html
+/// https://clang.llvm.org/extra/clang-tidy/checks/bugprone/inconsistent-ifelse-braces.html
class InconsistentIfelseBracesCheck : public ClangTidyCheck {
public:
InconsistentIfelseBracesCheck(StringRef Name, ClangTidyContext *Context)
@@ -30,7 +30,7 @@ class InconsistentIfelseBracesCheck : public ClangTidyCheck {
const IfStmt *If);
void checkStmt(const ast_matchers::MatchFinder::MatchResult &Result,
const Stmt *S, SourceLocation StartLoc,
- SourceLocation EndLocHint = SourceLocation());
+ SourceLocation EndLocHint = {});
};
} // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index 4c5b70f6c47e5..99286f548cda1 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -257,7 +257,7 @@ Clang-Tidy Checks
:doc:`llvm-prefer-static-over-anonymous-namespace <llvm/prefer-static-over-anonymous-namespace>`,
:doc:`llvm-twine-local <llvm/twine-local>`, "Yes"
:doc:`llvm-use-new-mlir-op-builder <llvm/use-new-mlir-op-builder>`, "Yes"
- :doc:`llvm-use-ranges <llvm/use-ranges>`,
+ :doc:`llvm-use-ranges <llvm/use-ranges>`, "Yes"
:doc:`llvmlibc-callee-namespace <llvmlibc/callee-namespace>`,
:doc:`llvmlibc-implementation-in-namespace <llvmlibc/implementation-in-namespace>`,
:doc:`llvmlibc-inline-function-decl <llvmlibc/inline-function-decl>`, "Yes"
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
index 3d4af258137ce..dd76e7176e445 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s bugprone-inconsistent-ifelse-braces %t
+// RUN: %check_clang_tidy -std=c++98-or-later %s bugprone-inconsistent-ifelse-braces %t
bool cond(const char *) { return false; }
>From 540a43cf30a77c0c30a0bb459c26e2796919087d Mon Sep 17 00:00:00 2001
From: Davide Cunial <dcunial at proton.me>
Date: Thu, 30 Oct 2025 20:35:43 +0100
Subject: [PATCH 6/6] [clang-tidy] Add some test for constexpr if
---
...nconsistent-ifelse-braces-consteval-if.cpp | 1 -
...nconsistent-ifelse-braces-constexpr-if.cpp | 122 ++++++++++++++++++
.../bugprone/inconsistent-ifelse-braces.cpp | 1 -
3 files changed, 122 insertions(+), 2 deletions(-)
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-constexpr-if.cpp
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp
index 3eb51c39e2921..c42b353e9d242 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-consteval-if.cpp
@@ -1,7 +1,6 @@
// RUN: %check_clang_tidy -std=c++23-or-later %s bugprone-inconsistent-ifelse-braces %t
bool cond(const char *) { return false; }
-
void do_something(const char *) {}
// Positive tests.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-constexpr-if.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-constexpr-if.cpp
new file mode 100644
index 0000000000000..f8a3d67fcfbd1
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces-constexpr-if.cpp
@@ -0,0 +1,122 @@
+// RUN: %check_clang_tidy -std=c++17-or-later %s bugprone-inconsistent-ifelse-braces %t
+
+constexpr bool cond(const char *) { return false; }
+constexpr void do_something(const char *) {}
+
+// Positive tests.
+void f() {
+ if constexpr (cond("if0") /*comment*/) do_something("if-same-line");
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-3]]:41: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if constexpr (cond("if0") /*comment*/) { do_something("if-same-line");
+ // CHECK-FIXES: } else {
+
+ if constexpr (cond("if0.1") /*comment*/) {
+ } else do_something("else-same-line");
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else { do_something("else-same-line");
+ // CHECK-FIXES: }
+
+ if constexpr (cond("if1"))
+ do_something("if-single-line");
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-4]]:29: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if constexpr (cond("if1")) {
+ // CHECK-FIXES: } else {
+
+ if constexpr (cond("if1.1")) {
+ } else
+ do_something("else-single-line");
+ // CHECK-MESSAGES: :[[@LINE-2]]:9: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else {
+ // CHECK-FIXES: }
+
+ if constexpr (cond("if2") /*comment*/)
+ // some comment
+ do_something("if-multi-line");
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-5]]:41: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if constexpr (cond("if2") /*comment*/) {
+ // CHECK-FIXES: } else {
+
+ if constexpr (cond("if2.1") /*comment*/) {
+ } else
+ // some comment
+ do_something("else-multi-line");
+ // CHECK-MESSAGES: :[[@LINE-3]]:9: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else {
+ // CHECK-FIXES: }
+
+ if constexpr (cond("if3")) do_something("elseif-same-line");
+ else if constexpr (cond("if3")) {
+ } else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-4]]:29: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if constexpr (cond("if3")) { do_something("elseif-same-line");
+ // CHECK-FIXES: } else if constexpr (cond("if3")) {
+
+ if constexpr (cond("if3.1")) {
+ } else if constexpr (cond("if3.1")) do_something("elseif-same-line");
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-3]]:38: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else if constexpr (cond("if3.1")) { do_something("elseif-same-line");
+ // CHECK-FIXES: } else {
+
+ if constexpr (cond("if3.2")) {
+ } else if constexpr (cond("if3.2")) {
+ } else do_something("else-same-line");
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else { do_something("else-same-line");
+ // CHECK-FIXES: }
+
+ if constexpr (cond("if4-outer"))
+ if constexpr (cond("if4-inner"))
+ do_something("if-single-line");
+ else {
+ }
+ else {
+ }
+ // CHECK-MESSAGES: :[[@LINE-7]]:35: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-MESSAGES: :[[@LINE-7]]:37: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if constexpr (cond("if4-outer")) {
+ // CHECK-FIXES: if constexpr (cond("if4-inner")) {
+ // CHECK-FIXES: } else {
+ // CHECK-FIXES: } else {
+
+ if constexpr (cond("if5"))
+ do_something("if-single-line");
+ else if constexpr (cond("if5")) {
+ }
+ // CHECK-MESSAGES: :[[@LINE-4]]:29: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: if constexpr (cond("if5")) {
+ // CHECK-FIXES: } else if constexpr (cond("if5")) {
+
+ if constexpr (cond("if5.1")) {
+ } else if constexpr (cond("if5.1"))
+ do_something("elseif-single-line");
+ // CHECK-MESSAGES: :[[@LINE-2]]:38: warning: <message> [bugprone-inconsistent-ifelse-braces]
+ // CHECK-FIXES: } else if constexpr (cond("if5.1")) {
+ // CHECK-FIXES: }
+}
+
+// Negative tests.
+void g() {
+ if constexpr (cond("if0")) {
+ do_something("if-single-line");
+ } else if constexpr (cond("if0")) {
+ do_something("elseif-single-line");
+ } else {
+ do_something("else-single-line");
+ }
+
+ if constexpr (cond("if1"))
+ do_something("if-single-line");
+ else if constexpr (cond("if1"))
+ do_something("elseif-single-line");
+ else
+ do_something("else-single-line");
+}
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
index dd76e7176e445..bcb97a1766a03 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/inconsistent-ifelse-braces.cpp
@@ -1,7 +1,6 @@
// RUN: %check_clang_tidy -std=c++98-or-later %s bugprone-inconsistent-ifelse-braces %t
bool cond(const char *) { return false; }
-
void do_something(const char *) {}
// Positive tests.
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