Span allows undesirable conversions

[melak47]

Describe the bug
Span<Base> can be constructed from Span<Derived> (or some container of Derived), but iterating over (or indexing) into that Span<Base> will cause undefined behavior if sizeof(Base) != sizeof(Derived).

Expected behavior
The constructors should only allow cv qualifier adjustments, like Span<int> -> Span<const int>, not everything that is permitted by static_cast<pointer>(source.data()).

[lamarrr]

Thanks for landing the fix. I'd argue that it should be allowed since we are propagating the behavior of the pointer type

[melak47]

Hm, maybe the conversion could be made explicit for such cases, rather than disallowed entirely.

[lamarrr]

Hm, maybe the conversion could be made explicit for such cases, rather than disallowed entirely.

True true. That makes sense then.
Closing this issue as resolved.