From 5c2a2a5c2272b0b70e3b0d6b45bf361e384fb6a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Wed, 31 Dec 2014 15:14:22 +0100
Subject: [PATCH] Fixed #6095 (False positive oppositeInnerCondition -
 neglecting statements with side-effects)

---
 lib/checkcondition.cpp |  4 ++++
 test/testcondition.cpp | 31 +++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/lib/checkcondition.cpp b/lib/checkcondition.cpp
index 3e3eb2656..2beffb61e 100644
--- a/lib/checkcondition.cpp
+++ b/lib/checkcondition.cpp
@@ -426,6 +426,10 @@ void CheckCondition::oppositeInnerCondition()
                 }
                 if (Token::Match(tok->previous(), "++|--|& %var%"))
                     break;
+                if (Token::Match(tok, "%var% . %var% (") &&
+                    !tok->variable()->isConst() &&
+                    !(tok->tokAt(2)->function() && tok->tokAt(2)->function()->isConst))
+                    break;
                 if (Token::Match(tok->previous(), "[(,] %var% [,)]")) {
                     // is variable unchanged? default is false..
                     bool unchanged = false;
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
index bee2374fd..8ac0a8c8e 100644
--- a/test/testcondition.cpp
+++ b/test/testcondition.cpp
@@ -1062,6 +1062,37 @@ private:
               "}");
         ASSERT_EQUALS("", errout.str());
 
+        {
+            // #6095 - calling member function that might change the state
+            check("void f() {\n"
+                  "  const Fred fred;\n" // <- fred is const, warn
+                  "  if (fred.isValid()) {\n"
+                  "    fred.dostuff();\n"
+                  "    if (!fred.isValid()) {}\n"
+                  "  }\n"
+                  "}");
+            ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:5]: (warning) Opposite conditions in nested 'if' blocks lead to a dead code block.\n", errout.str());
+
+            check("class Fred { public: void dostuff() const; };\n"
+                  "void f() {\n"
+                  "  Fred fred;\n"
+                  "  if (fred.isValid()) {\n"
+                  "    fred.dostuff();\n" // <- dostuff() is const, warn
+                  "    if (!fred.isValid()) {}\n"
+                  "  }\n"
+                  "}");
+            ASSERT_EQUALS("[test.cpp:4] -> [test.cpp:6]: (warning) Opposite conditions in nested 'if' blocks lead to a dead code block.\n", errout.str());
+
+            check("void f() {\n"
+                  "  Fred fred;\n"
+                  "  if (fred.isValid()) {\n"
+                  "    fred.dostuff();\n"
+                  "    if (!fred.isValid()) {}\n"
+                  "  }\n"
+                  "}");
+            ASSERT_EQUALS("", errout.str());
+        }
+
         // #5731 - fp when undeclared variable is used
         check("void f() {\n"
               "   if (x == -1){\n"