[CI] miri test fails due to `rkyv`lib

[mablr]

Abstract

Therkyv's lib ArchivedVec::as_slice()method triggers a Stacked Borrows violation when running tests under miri.

Reproduction

Test location:

core/crates/primitives/src/bytes/rkyv.rs

Lines 49 to 59 in 52a263d

	#[test]
	fn rkyv_roundtrip() {
	let bytes = Bytes::from_static(&[1, 35, 69, 103, 137, 171, 205, 239]);
	let ser = rkyv::to_bytes::<rancor::BoxedError>(&bytes).unwrap();
	let archived = rkyv::access::<Archived<Bytes>, rancor::BoxedError>(&ser).unwrap();
	assert_eq!(bytes.as_ref(), archived.as_slice());
	let des = rkyv::deserialize::<Bytes, rancor::BoxedError>(archived).unwrap();
	assert_eq!(bytes, des);
	}

Command:

cargo +nightly miri test --all-features

Error:

  error: Undefined Behavior: trying to retag from <...> for SharedReadOnly permission,
  but that tag does not exist in the borrow stack for this location

Environment:

• rkyv 0.8.12
• nightly Rust with miri

Fix ?

Is it acceptable to mark rkyv_roundtrip test as #[cfg(not(miri))] ?

[dipanshuhappy]

Happy to work on this

[mablr]

Thx, btw it's just a matter of one line ;)

Let’s first get the feedback from a core team member.

[mablr]

I'm wondering if the CI failure here #1041 is related 🧐 (not able to reproduce locally)