I.12 not_null has converting constructors?

[akrzemi1]

It might be more about GSL than this project. It seems to me that offering a conversion from T to not_null looses the potential to detect certain bugs at compile-time.

if I have a function that returns a raw (potentially null) pointer, and I carelessly pass it to a function taking not_null it will compile fine, and will try report a bug at run-time when it is likely too late.

Instead, if the constructor from T were explicit, an inadvertent assignment:

use_ptr(make_ptr());

would be impossible, and I would be forced to explicitly require a potentially unsafe conversion:

use_ptr(not_null<T>{make_ptr()});

This would be a kind of the signature: by writing this cast, I am taking the responsibility for guaranteeing that the raw pointer will not be null. If it is not the case, you will know that I did it consciously.

[akrzemi1]

I really consider this converting constructor a safety issue.

[AndrewPardoe]

Thank you for moving this issue to the GSL repo. Closing this as a stale issue.