8f1cec8d84
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 <jack@wrenn.fyi>
26 lines
980 B
Plaintext
26 lines
980 B
Plaintext
error[E0277]: `Unit` cannot be safely transmuted into `u8` in the defining scope of `assert::Context`
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--> $DIR/unit-to-u8.rs:23:52
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LL | assert::is_maybe_transmutable::<&'static Unit, &'static u8>();
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| ^^^^^^^^^^^ The size of `Unit` is smaller than the size of `u8`
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note: required by a bound in `is_maybe_transmutable`
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--> $DIR/unit-to-u8.rs:10:14
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LL | pub fn is_maybe_transmutable<Src, Dst>()
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| --------------------- required by a bound in this function
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LL | where
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LL | Dst: BikeshedIntrinsicFrom<Src, Context, {
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| ______________^
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LL | | Assume {
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LL | | alignment: true,
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LL | | lifetimes: true,
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... |
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LL | | }
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LL | | }>
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| |__________^ required by this bound in `is_maybe_transmutable`
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error: aborting due to previous error
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For more information about this error, try `rustc --explain E0277`.
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