From 6875514e594dcfb009119da4fa7e661430f9f63e Mon Sep 17 00:00:00 2001
From: chrchr-github <78114321+chrchr-github@users.noreply.github.com>
Date: Mon, 13 May 2024 18:06:47 +0200
Subject: [PATCH] Fix #12725 oppositeInnerCondition with negated bool (#6401)

---
 lib/checkcondition.cpp | 2 +-
 test/testcondition.cpp | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/checkcondition.cpp b/lib/checkcondition.cpp
index 70fa4d9ae33..bc1df36aacc 100644
--- a/lib/checkcondition.cpp
+++ b/lib/checkcondition.cpp
@@ -716,7 +716,7 @@ void CheckCondition::multiCondition2()
 
                     // Condition..
                     const Token *cond2 = tok->str() == "if" ? condStartToken->astOperand2() : condStartToken->astOperand1();
-                    const bool isReturnVar = (tok->str() == "return" && !Token::Match(cond2, "%cop%"));
+                    const bool isReturnVar = (tok->str() == "return" && (!Token::Match(cond2, "%cop%") || (cond2 && cond2->isUnaryOp("!"))));
 
                     ErrorPath errorPath;
 
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
index db044308c71..1a535ff0bf0 100644
--- a/test/testcondition.cpp
+++ b/test/testcondition.cpp
@@ -2129,6 +2129,15 @@ class TestCondition : public TestFixture {
               "    bool m_value = false;\n"
               "};");
         ASSERT_EQUALS("", errout_str());
+
+        // #12725
+        check("bool f(bool b) {\n"
+              "    if (b)\n"
+              "        return !b;\n"
+              "    b = g();\n"
+              "    return b;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Return value '!b' is always false\n", errout_str());
     }
 
     void oppositeInnerConditionPointers() {