Question: Are we just removing the implicit evaluation to bool, or also the implicit cast to pointer? It would seem strange to deprecate one but not the other, in the sense that implicit cast to pointer implies implicit cast to bool.

Long story short: Shouldn't this also be changed to `delete _matrix.ptr`.

Also, while I realize that delete is deprecated, 2D allocation implies jagged allocation, so I think the code should actually read:
```D
foreach( arr; _matrix)
    delete arr.ptr;
delete _matrix.ptr;
```
Unless delete "knows" how to handle 2D deletion?

Well, I suppose at this point, it's outside the boundaries of your pull anyways...