Support use of 'this->' when checking operator=() return type

lib/checkclass.cpp

@@ -924,6 +924,7 @@ void CheckClass::checkReturnPtrThis(const Scope *scope, const Function *func, co
             else if (!(Token::Match(tok->tokAt(1), "(| * this ;|=") ||
                        Token::Match(tok->tokAt(1), "(| * this +=") ||
                        Token::simpleMatch(tok->tokAt(1), "operator= (") ||
+                       Token::simpleMatch(tok->tokAt(1), "this . operator= (") ||
                        (Token::Match(tok->tokAt(1), "%type% :: operator= (") &&
                         tok->next()->str() == scope->className)))
                 operatorEqRetRefThisError(func->token);

test/testclass.cpp

@@ -452,6 +452,16 @@ private:
             "A &A::operator =(int *other) { return (*this;) };\n"
             "A &A::operator =(long *other) { return operator = (*(int *)other); };");
         ASSERT_EQUALS("", errout.str());
+
+        checkOpertorEqRetRefThis(
+            "class A {\n"
+            "public:\n"
+            "  A &operator =(int *other);\n"
+            "  A &operator =(long *other);\n"
+            "};\n"
+            "A &A::operator =(int *other) { return (*this;) };\n"
+            "A &A::operator =(long *other) { return this->operator = (*(int *)other); };");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void operatorEqRetRefThis4()