Make stable_mir::with_tables sound by oli-obk · Pull Request #120128 · rust-lang/rust (original) (raw)

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See the first commit for the actual soundness fix. The rest is just fallout from that and is entirely safe code. Includes most of #120120

The major difference to #120120 is that we don't need an unsafe trait, as we can now rely on the type system (the only unsafe part, and the actual source of the unsoundness was in with_tables)

r? @celinval

We were able to uplift any value from Tables to 'static, which is unsound.

The internal function was unsound, it could cause UB in rare cases where the user inadvertly stored the returned object in a location that could outlive the TyCtxt.

In order to make it safe, we now take a type context as an argument to the internal fn, and we ensure that interned items are lifted using the provided context.

Thus, this change ensures that the compiler can properly enforce that the object does not outlive the type context it was lifted to.

rustbot added S-waiting-on-review

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Jan 19, 2024

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📌 Commit 6cd6539 has been approved by celinval

It is now in the queue for this repository.

bors added S-waiting-on-bors

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and removed S-waiting-on-review

Status: Awaiting review from the assignee but also interested parties.

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Jan 21, 2024

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request

Jan 21, 2024

…nval

Make stable_mir::with_tables sound

See the first commit for the actual soundness fix. The rest is just fallout from that and is entirely safe code. Includes most of rust-lang#120120

The major difference to rust-lang#120120 is that we don't need an unsafe trait, as we can now rely on the type system (the only unsafe part, and the actual source of the unsoundness was in with_tables)

r? @celinval

This was referenced

Jan 21, 2024