e4417cf020
Initial implementation of transmutability trait. *T'was the night before Christmas and all through the codebase, not a miri was stirring — no hint of `unsafe`!* This PR provides an initial, **incomplete** implementation of *[MCP 411: Lang Item for Transmutability](https://github.com/rust-lang/compiler-team/issues/411)*. The `core::mem::BikeshedIntrinsicFrom` trait provided by this PR is implemented on-the-fly by the compiler for types `Src` and `Dst` when the bits of all possible values of type `Src` are safely reinterpretable as a value of type `Dst`. What this PR provides is: - [x] [support for transmutations involving primitives](https://github.com/jswrenn/rust/tree/transmute/src/test/ui/transmutability/primitives) - [x] [support for transmutations involving arrays](https://github.com/jswrenn/rust/tree/transmute/src/test/ui/transmutability/arrays) - [x] [support for transmutations involving structs](https://github.com/jswrenn/rust/tree/transmute/src/test/ui/transmutability/structs) - [x] [support for transmutations involving enums](https://github.com/jswrenn/rust/tree/transmute/src/test/ui/transmutability/enums) - [x] [support for transmutations involving unions](https://github.com/jswrenn/rust/tree/transmute/src/test/ui/transmutability/unions) - [x] [support for weaker validity checks](https://github.com/jswrenn/rust/blob/transmute/src/test/ui/transmutability/unions/should_permit_intersecting_if_validity_is_assumed.rs) (i.e., `Assume::VALIDITY`) - [x] visibility checking What isn't yet implemented: - [ ] transmutability options passed using the `Assume` struct - [ ] [support for references](https://github.com/jswrenn/rust/blob/transmute/src/test/ui/transmutability/references.rs) - [ ] smarter error messages These features will be implemented in future PRs. |
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| README.md | ||
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