If you implement closures as thunks, you can just free them when done, no need for GC. closure int foo(int x) {return x + y;} int(*foo_p)(int) = malloc

If you implement closures as thunks, you can just free them when done, no need for GC. closure int foo(int x) {return x + y;} int(*foo_p)(int) = malloc(sizeof(foo)); memcpy(foo_p,&foo,sizeof(foo)); return foo_p; So, you can add working closures in one keyword (and possibly a special case for function pointer decay).