On 1/29/2019 3:45 AM, Andrei Alexandrescu wrote:
> I am talking about this:
>
> int[] a = cast(int[]) alloc.allocate(100 * int.sizeof);
> if (alloc.reallocate(a, 200 * int.sizeof)
> {
>      assert(a.length == 200);
> }

Even simpler:

   void func(ref void* p) {
     free(p);                     // frees (1)
     p = malloc(100);              // (2)
   }

   int* p = cast(int*)malloc(16);  // (1)
   func(p);                        // p copied to temp for conversion to void*
   free(p);                        // frees (1) again
                                   // (2) is left dangling

It's a memory corruption issue, with no way to detect it.