[tracking issue] const fn std::mem::needs_drop

[Havvy]

The issue title says it all really. std::mem::needs_drop is a function that doesn't change from call to call once monomorphized, so it should be a const function.

EDIT:

This has been implemented and it is waiting for stabilization now.

[oli-obk]

blocked on #51570

[JoshBrudnak]

@oli-obk is this still blocked? If not I would like to help out with it. 👍

[oli-obk]

Should be fine to add behind a feature gate.

The steps are basically the same as #51171 and #51299 (but you can do them in a single PR)

[mjbshaw]

It might be nice to keeps this issue open until const_needs_drop is stabilized.