15 lines
491 B
Rust
15 lines
491 B
Rust
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trait Super {}
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trait Sub: Super {}
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struct Wrapper<T: ?Sized>(T);
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// This cast should not compile.
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// Upcasting can't work here, because we are also changing the type (`Wrapper`),
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// and reinterpreting would be confusing/surprising.
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// See <https://github.com/rust-lang/rust/pull/120248#discussion_r1487739518>
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fn cast(ptr: *const dyn Sub) -> *const Wrapper<dyn Super> {
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ptr as _ //~ error: casting `*const (dyn Sub + 'static)` as `*const Wrapper<dyn Super>` is invalid
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}
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fn main() {}
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