rust/compiler/rustc_transmute/src/maybe_transmutable/mod.rs, branch 1.76.0

Remove the `MaybeTransmutableQuery<&'l Dfa<...>, C>` impl.

2023-10-06T00:25:32+00:00

Because there is also a `MaybeTransmutableQuery, C>` impl, and we don't need both.

Fix a comment.

2023-10-06T00:22:06+00:00

It was duplicated from the method above.

Remove `map_layouts`.

2023-10-06T00:21:08+00:00

As per the `FIXME` comment, it's an abstraction that makes the code harder to read.

Fix error report for size overflow from transmute

2023-09-05T22:48:34+00:00

Safe Transmute: Refactor error handling and Answer type

2023-06-12T23:56:21+00:00

- Create `Answer` type that is not just a type alias of `Result` - Remove a usage of `map_layouts` to make the code easier to read - Don't hide errors related to Unknown Layout when computing transmutability

Safe Transmute: Update definition of Condition type

2023-05-25T00:49:56+00:00

- Change `Condition` to not contain `Answer`s but instead just contain other `Condition`s directly. - Also improve error reporting for `DstHasStricterAlignment`

Safe Transmute: Check mutability before creating dst -> src obligation

2023-05-24T22:00:06+00:00

- Only create dst -> src obligation if Dst is mutable - Add some long comments to explain parts of the transmutability code that were unclear to me when reading - Update/add tests

Safe Transmute: Fix propagation of errors

2023-05-24T21:52:19+00:00

- Make sure that the most specific Reason is the one that bubbles up when we are folding over the `Answer` tree. `Reason::DstIsBitIncompatible` is the least specific, so that should be used only when there isn't anything else available. - Small fixes where we used the wrong Reason variant. - Tiny cleanups

Safe Transmute: Change Answer type to Result

2023-05-24T21:52:19+00:00

This patch updates the `Answer` type from `rustc_transmute` so that it just a type alias to `Result`. This makes it so that the standard methods for `Result` can be used to process the `Answer` tree, including being able to make use of the `?` operator on `Answer`s. Also, remove some unused functions

Safe Transmute: Enable handling references, including recursive types

2023-05-24T21:52:18+00:00

This patch enables support for references in Safe Transmute, by generating nested obligations during trait selection. Specifically, when we call `confirm_transmutability_candidate(...)`, we now recursively traverse the `rustc_transmute::Answer` tree and create obligations for all the `Answer` variants, some of which include multiple nested `Answer`s. Also, to handle recursive types, enable support for coinduction for the Safe Transmute trait (`BikeshedIntrinsicFrom`) by adding the `#[rustc_coinduction]` annotation. Also fix some small logic issues when reducing the `or` and `and` combinations in `rustc_transmute`, so that we don't end up with additional redundant `Answer`s in the tree. Co-authored-by: Jack Wrenn