mirror of https://github.com/rust-lang/rust
28 lines
1.1 KiB
Rust
28 lines
1.1 KiB
Rust
// The "projection gap" is particularly "fun" around higher-ranked
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// projections. This is because the current code is hard-coded to say
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// that a projection that contains escaping regions, like `<T as
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// Trait2<'y, 'z>>::Foo` where `'z` is bound, can only be found to
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// outlive a region if all components that appear free (`'y`, where)
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// outlive that region. However, we DON'T add those components to the
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// implied bounds set, but rather we treat projections with escaping
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// regions as opaque entities, just like projections without escaping
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// regions.
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trait Trait1<T> { }
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trait Trait2<'a, 'b> {
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type Foo;
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}
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// As a side-effect of the conservative process above, the type of
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// this argument `t` is not automatically considered well-formed,
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// since for it to be WF, we would need to know that `'y: 'x`, but we
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// do not infer that.
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fn callee<'x, 'y, T>(t: &'x dyn for<'z> Trait1< <T as Trait2<'y, 'z>>::Foo >)
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//~^ ERROR the trait bound `for<'z> T: Trait2<'y, 'z>` is not satisfied
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{
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//~^ ERROR the trait bound `for<'z> T: Trait2<'y, 'z>` is not satisfied
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}
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fn main() { }
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