How to use joern to analysis memory leak？

Question

How to query cpg of this code to find the location of un-free memory ?

int bad(void) {  
    OutsideType my;
    my.p = MyAlloc();
    my.p = MyAlloc(); 
    MyFree(my.p);  
    return 0; 
}

Try using joern to find the place where the free function is called.