30 lines
796 B
Rust
30 lines
796 B
Rust
//@ revisions: current next
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//@[next] compile-flags: -Znext-solver
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//@ ignore-compare-mode-next-solver (explicit revisions)
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//@[current] check-pass
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//@[current] known-bug: #57893
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// Should fail. Because we see an impl that uses a certain associated type, we
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// type-check assuming that impl is used. However, this conflicts with the
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// "implicit impl" that we get for trait objects, violating coherence.
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trait Object<U> {
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type Output;
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}
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impl<T: ?Sized, U> Object<U> for T {
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type Output = U;
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}
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fn foo<T: ?Sized, U>(x: <T as Object<U>>::Output) -> U {
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x
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}
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#[allow(dead_code)]
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fn transmute<T, U>(x: T) -> U {
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foo::<dyn Object<U, Output = T>, U>(x)
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//[next]~^ ERROR type annotations needed: cannot normalize `<dyn Object<U, Output = T> as Object<U>>::Output`
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}
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fn main() {}
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