Returns true if the pointer is null.

Note that unsized types have many possible null pointers, as only the raw data pointer is considered, not their length, vtable, etc. Therefore, two pointers that are null may still not compare equal to each other.

Panics during const evaluation

If this method is used during const evaluation, and self is a pointer that is offset beyond the bounds of the memory it initially pointed to, then there might not be enough information to determine whether the pointer is null. This is because the absolute address in memory is not known at compile time. If the nullness of the pointer cannot be determined, this method will panic.

In-bounds pointers are never null, so the method will never panic for such pointers.