hashbrown is not following strict provenance

[RalfJung]

hashbrown is using int-to-ptr casts in some places, instead of the strict provenance APIs:

hashbrown/src/raw/mod.rs

Line 306 in 09dc17e

(index + 1) as *mut T

hashbrown/src/raw/mod.rs

Line 326 in 09dc17e

mem::align_of::<T>() as *mut T

hashbrown/src/raw/mod.rs

Line 334 in 09dc17e

(self.ptr.as_ptr() as usize + offset) as *mut T

(there might be more)

The cases I have found so far are all inside if Self::IS_ZERO_SIZED_TYPE {, so I assume these are "fake" pointers that are never dereferenced, and could be using ptr::invalid_mut.

The fuzzy_provenance_casts lint can be used to statically check for such casts. Currently however the strict provenance functions are still unstable.

[zakarumych]

Should hashbrown use sptr crate for the time Strict Provenance API is unstable?

[RalfJung]

@Amanieu is there a usual cadence for syncing hashbrown changes to the standard library?

Looks like the version shipped with current nightly still has the old int2ptr casts in it.

[Amanieu]

We currently have several breaking changes on master, and I'm finishing up some new feature which will be released in hashbrown 0.14. I think the release should happen in the next week or two.

[RalfJung]

Cool, thanks for the update!