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

[Abhay Singh via cfe-commits]

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

Fixes #230601

This PR addresses the false-negative scenario where 
`bugprone-redundant-branch-condition` fails to trigger on simple two-variable 
logical conjunction expressions (e.g., `if (x && y) { if (y) ... }`). 

Note: This is a partial fix. As noted in the code's `// FIXME` comments, 
handling longer conjunctive and disjunctive chain clauses (3 or more variables) 
requires further extension is not yet touched.


>From 6463170b54e1022bddefdbf040869e3e8cf9f711 Mon Sep 17 00:00:00 2001
From: abhay13332 <abhaysingh13072...@gmail.com>
Date: Sun, 11 Oct 2026 01:09:35 +0530
Subject: [PATCH] [clang-tidy] Fix false negative for binary logical
 expressions for two operands in bugprone-redundant-branch-condition

---
 .../bugprone/RedundantBranchConditionCheck.cpp  |  7 +++----
 .../bugprone/redundant-branch-condition.cpp     | 17 +++++++++++++++--
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git 
a/clang-tools-extra/clang-tidy/bugprone/RedundantBranchConditionCheck.cpp 
b/clang-tools-extra/clang-tidy/bugprone/RedundantBranchConditionCheck.cpp
index 8d608dd4b0e66..f6c6373969b34 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/test/clang-tidy/checkers/bugprone/redundant-branch-condition.cpp
 
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/redundant-branch-condition.cpp
index ad2238ff9984f..1111c27ef01f4 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 
--------------------------------------------------===//
@@ -278,13 +278,26 @@ 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();
   if (fireFighters < 10 && onFire) {
     if (someOtherCondition()) {
       if (onFire) {
-        // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: redundant condition 
'onFire' [bugprone-redundant-branch-condition]
+        // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: redundant condition 
'onFire' [bugprone-redundant-branch-condition]
         // CHECK-FIXES: {{^\ *$}}
         scream();
       }

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