Fixed #8412 (ignoredReturnValue not issued when return value is changed but not really used (by logical not for example))

lib/checkfunctions.cpp

@@ -204,7 +204,10 @@ void CheckFunctions::checkIgnoredReturnValue()
             if (tok->varId() || !Token::Match(tok, "%name% (") || tok->isKeyword())
                 continue;
 
-            if (tok->next()->astParent())
+            const Token *parent = tok->next()->astParent();
+            while (Token::Match(parent, "%cop%"))
+                parent = parent->astParent();
+            if (parent)
                 continue;
 
             if (!tok->scope()->isExecutable()) {

test/testfunctions.cpp

@@ -1231,6 +1231,13 @@ private:
               "}\n"
               "A g() { return f(1); }");
         ASSERT_EQUALS("", errout.str());
+
+        // #8412 - unused operator result
+        check("void foo() {\n"
+              "  !mystrcmp(a, b);\n"
+              "}", "test.cpp", &settings2);
+        ASSERT_EQUALS("[test.cpp:2]: (warning) Return value of function mystrcmp() is not used.\n", errout.str());
+
     }
 
     void checkIgnoredErrorCode() {