From 0b751dcc1b35afdf9ae1f7fcaa233620569fae80 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Fri, 1 Sep 2017 23:24:15 +0200
Subject: [PATCH] Opposite conditions: Better matching when outer condition
 uses &&

---
 lib/astutils.cpp       |  8 +++++++-
 lib/checkcondition.cpp |  4 ++--
 test/testcondition.cpp | 10 ++++++++++
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/lib/astutils.cpp b/lib/astutils.cpp
index 608374731..bb923df57 100644
--- a/lib/astutils.cpp
+++ b/lib/astutils.cpp
@@ -256,8 +256,14 @@ bool isOppositeCond(bool isNot, bool cpp, const Token * const cond1, const Token
     if (cond2->str() == "!")
         return isOppositeCond(isNot, cpp, cond2, cond1, library, pure);
 
-    if (!cond1->isComparisonOp() || !cond2->isComparisonOp())
+    if (!cond1->isComparisonOp() || !cond2->isComparisonOp()) {
+        if (!isNot && cond1->str() == "&&" && cond2->isComparisonOp()) {
+            return isOppositeCond(isNot, cpp, cond1->astOperand1(), cond2, library, pure) ||
+                   isOppositeCond(isNot, cpp, cond1->astOperand2(), cond2, library, pure);
+        }
+
         return false;
+    }
 
     const std::string &comp1 = cond1->str();
 
diff --git a/lib/checkcondition.cpp b/lib/checkcondition.cpp
index bbb09bb6f..e8ac2d8e5 100644
--- a/lib/checkcondition.cpp
+++ b/lib/checkcondition.cpp
@@ -540,7 +540,7 @@ void CheckCondition::oppositeInnerCondition()
         const Token *cond2 = ifToken->next()->astOperand2();
 
         if (isOppositeCond(false, _tokenizer->isCPP(), cond1, cond2, _settings->library, true))
-            oppositeInnerConditionError(scope->classDef, cond2);
+            oppositeInnerConditionError(cond1, cond2);
     }
 }
 
@@ -548,7 +548,7 @@ void CheckCondition::oppositeInnerConditionError(const Token *tok1, const Token*
 {
     ErrorPath errorPath;
     errorPath.push_back(ErrorPathItem(tok1, "outer condition"));
-    errorPath.push_back(ErrorPathItem(tok2, "opposite inner condition => always false when outer condition is true"));
+    errorPath.push_back(ErrorPathItem(tok2, "opposite inner condition"));
     reportError(errorPath, Severity::warning, "oppositeInnerCondition", "Opposite inner 'if' condition leads to a dead code block.", CWE398, false);
 }
 
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
index 5598de32c..62fac42b2 100644
--- a/test/testcondition.cpp
+++ b/test/testcondition.cpp
@@ -77,6 +77,7 @@ private:
 
         TEST_CASE(oppositeInnerCondition);
         TEST_CASE(oppositeInnerCondition2);
+        TEST_CASE(oppositeInnerConditionAnd);
 
         TEST_CASE(clarifyCondition1);     // if (a = b() < 0)
         TEST_CASE(clarifyCondition2);     // if (a & b == c)
@@ -1699,6 +1700,15 @@ private:
                       , errout.str());
     }
 
+    void oppositeInnerConditionAnd() {
+        check("void f(int x) {\n"
+              "  if (a>3 && x > 100) {\n"
+              "    if (x < 10) {}\n"
+              "  }"
+              "}");
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (warning) Opposite inner 'if' condition leads to a dead code block.\n", errout.str());
+    }
+
     // clarify conditions with = and comparison
     void clarifyCondition1() {
         check("void f() {\n"