Fixed #2502 (False positive: redundant assingment of object to itself)

lib/checkother.cpp

@@ -317,12 +317,21 @@ void CheckOther::checkSelfAssignment()
     if (!_settings->_checkCodingStyle)
         return;
 
+    // POD variables..
+    std::set<unsigned int> pod;
+    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
+    {
+        if (tok->isStandardType() && tok->next()->varId() && Token::Match(tok->tokAt(2), "[,);]"))
+            pod.insert(tok->next()->varId());
+    }
+
     const char selfAssignmentPattern[] = "%var% = %var% ;|=|)";
     const Token *tok = Token::findmatch(_tokenizer->tokens(), selfAssignmentPattern);
     while (tok)
     {
         if (Token::Match(tok->previous(), "[;{}]") &&
-            tok->varId() && tok->varId() == tok->tokAt(2)->varId())
+            tok->varId() && tok->varId() == tok->tokAt(2)->varId() &&
+            pod.find(tok->varId()) != pod.end())
         {
             selfAssignmentError(tok, tok->str());
         }

test/testother.cpp

@@ -1157,14 +1157,12 @@ private:
         check("void foo()\n"
               "{\n"
               "        int x = x;\n"
-              "        return 0;\n"
               "}\n");
         ASSERT_EQUALS("[test.cpp:3]: (warning) Redundant assignment of \"x\" to itself\n", errout.str());
 
         check("void foo()\n"
               "{\n"
               "        std::string var = var = \"test\";\n"
-              "        return 0;\n"
               "}\n");
         TODO_ASSERT_EQUALS("[test.cpp:3]: (warning) Redundant assignment of \"var\" to itself\n", "", errout.str());
 
@@ -1182,6 +1180,13 @@ private:
               "        *x = x;\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        // non-primitive type -> there might be some side effects
+        check("void foo()\n"
+              "{\n"
+              "        Fred fred; fred = fred;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void testScanf1()