[clang-tools-extra] [clang-tidy] Fix false negative for binary logical expressions for tw… (PR #230846)

Abhay Singh via cfe-commits cfe-commits at lists.llvm.org
Tue Oct 13 01:50:04 PDT 2026


https://github.com/Abhay13332 updated https://github.com/llvm/llvm-project/pull/230846

>From 67518ef04dd71b7633f59aa4c63adb22d1a1043c Mon Sep 17 00:00:00 2001
From: abhay13332 <abhaysingh13072009 at gmail.com>
Date: Tue, 13 Oct 2026 14:02:59 +0530
Subject: [PATCH] [clang-tidy] Fix false negatives in
 bugprone-redundant-branch-condition on cases like if (x && y) { if (y) ... }

---
 .../bugprone/RedundantBranchConditionCheck.cpp    |  7 +++----
 clang-tools-extra/docs/ReleaseNotes.md            | 12 +++++++++---
 .../bugprone/redundant-branch-condition.cpp       | 15 ++++++++++++++-
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/bugprone/RedundantBranchConditionCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/RedundantBranchConditionCheck.cpp
index 8d608dd4b0e66..7934da1f2fbdd 100644
--- a/clang-tools-extra/clang-tidy/bugprone/RedundantBranchConditionCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/RedundantBranchConditionCheck.cpp
@@ -76,10 +76,9 @@ void RedundantBranchConditionCheck::registerMatchers(MatchFinder *Finder) {
       ifStmt(
           hasCondition(anyOf(
               declRefExpr(hasDeclaration(ImmutableVar)).bind(OuterIfVar1Str),
-              binaryOperator(
-                  hasOperatorName("&&"),
-                  hasEitherOperand(declRefExpr(hasDeclaration(ImmutableVar))
-                                       .bind(OuterIfVar2Str))))),
+              binaryOperator(hasOperatorName("&&"),
+                             forEach(declRefExpr(hasDeclaration(ImmutableVar))
+                                         .bind(OuterIfVar2Str))))),
           hasThen(hasDescendant(
               ifStmt(hasCondition(anyOf(
                          declRefExpr(hasDeclaration(
diff --git a/clang-tools-extra/docs/ReleaseNotes.md b/clang-tools-extra/docs/ReleaseNotes.md
index 1448005253556..c151210f68a4a 100644
--- a/clang-tools-extra/docs/ReleaseNotes.md
+++ b/clang-tools-extra/docs/ReleaseNotes.md
@@ -203,9 +203,15 @@ infrastructure are described first, followed by tool-specific sections.
   the pointer points to an incomplete (forward-declared) type.
 
 - Improved {doc}`bugprone-redundant-branch-condition
-  <clang-tidy/checks/bugprone/redundant-branch-condition>` check by fixing
-  false positives when the condition variable is changed later in a loop that
-  encloses the inner `if`.
+  <clang-tidy/checks/bugprone/redundant-branch-condition>` check:
+  
+    - Fixed false positives when the condition variable is changed later in a loop that
+      encloses the inner `if`.
+
+    - Fixed false negatives when there are two varibles statement in both side
+      of `&&` in `if` like `a && b` .it showing correct warning for first variable
+      and failed for second variable in if condition.eg.  `(x && y) { if (y) ... }`
+      in this example warning is not shown properly. 
 
 - Fixed a crash in {doc}`bugprone-std-namespace-modification
   <clang-tidy/checks/bugprone/std-namespace-modification>` when checking
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/redundant-branch-condition.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/redundant-branch-condition.cpp
index ad2238ff9984f..57ab6456a9987 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/redundant-branch-condition.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/redundant-branch-condition.cpp
@@ -12,7 +12,7 @@ bool tryToExtinguishByVal(bool);
 void tryPutFireOut();
 bool callTheFD();
 void scream();
-
+bool isFireFighterComing();
 bool someOtherCondition();
 
 //===--- Basic Positives --------------------------------------------------===//
@@ -278,6 +278,19 @@ void positive_direct_outer_and_rhs() {
     // CHECK-FIXES: {{^\ *$}}
   }
 }
+void positive_direct_outer_and_rhs_bool() {
+  bool onFire = isBurning();
+  bool isComing = isFireFighterComing();
+  if (isComing && onFire) {
+    if (onFire) {
+      // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: redundant condition 'onFire' [bugprone-redundant-branch-condition]
+      // CHECK-FIXES: {{^\ *$}}
+      scream();
+    }
+    // CHECK-FIXES: {{^\ *$}}
+  }
+}
+
 
 void positive_indirect_outer_and_rhs() {
   bool onFire = isBurning();



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