Fixed false positive redundantAssignment when operator() is called (#5568)

lib/checkother.cpp

@@ -772,6 +772,9 @@ void CheckOther::checkRedundantAssignment()
                 }
             } else if (Token::Match(tok, "%var% (")) { // Function call. Global variables might be used. Reset their status
                 const bool memfunc = Token::Match(tok, "memcpy|memmove|memset|strcpy|strncpy|sprintf|snprintf|strcat|strncat|wcscpy|wcsncpy|swprintf|wcscat|wcsncat");
+                if (tok->varId()) // operator() or function pointer
+                    varAssignments.erase(tok->varId());
+
                 if (memfunc) {
                     const Token* param1 = tok->tokAt(2);
                     writtenArgumentsEnd = param1->next();

test/testother.cpp

@@ -6249,6 +6249,13 @@ private:
               "}", nullptr, false, false, false, false);
         ASSERT_EQUALS("", errout.str());
 
+        check("void f() {\n"
+              "    Foo bar = foo();\n"
+              "    bar();\n" // #5568. operator() called
+              "    bar = y();\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+
         // Branch tests
         check("void f(int i) {\n"
               "    i = 1;\n"