35 lines
845 B
Rust
35 lines
845 B
Rust
// compile-flags: -Ztrait-solver=next
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// check-pass
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trait Trait {
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type Assoc: Sized;
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}
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impl Trait for &'static str {
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type Assoc = &'static str;
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}
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// Wrapper is just here to get around stupid `Sized` obligations in mir typeck
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struct Wrapper<T: ?Sized>(std::marker::PhantomData<T>);
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fn mk<T: Trait>(x: T) -> Wrapper<<T as Trait>::Assoc> { todo!() }
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trait IsStaticStr {}
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impl IsStaticStr for (&'static str,) {}
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fn define<T: IsStaticStr>(_: T) {}
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fn foo<'a, T: Trait>() {
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let y = Default::default();
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// `<?0 as Trait>::Assoc <: &'a str`
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// In the old solver, this would *equate* the LHS and RHS.
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let _: Wrapper<&'a str> = mk(y);
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// ... then later on, we constrain `?0 = &'static str`
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// but that should not mean that `'a = 'static`, because
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// we should use *sub* above.
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define((y,));
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}
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fn main() {}
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