mirror of https://github.com/rust-lang/rust
27 lines
663 B
Rust
27 lines
663 B
Rust
trait Dummy { fn dummy(&self); }
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fn foo1<'a:'b,'b>(x: &'a mut (dyn Dummy+'a)) -> &'b mut (dyn Dummy+'b) {
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// Here, we are able to coerce
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x
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}
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fn foo2<'a:'b,'b>(x: &'b mut (dyn Dummy+'a)) -> &'b mut (dyn Dummy+'b) {
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// Here, we are able to coerce
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x
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}
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fn foo3<'a,'b>(x: &'a mut dyn Dummy) -> &'b mut dyn Dummy {
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// Without knowing 'a:'b, we can't coerce
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x
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//~^ ERROR lifetime may not live long enough
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}
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struct Wrapper<T>(T);
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fn foo4<'a:'b,'b>(x: Wrapper<&'a mut dyn Dummy>) -> Wrapper<&'b mut dyn Dummy> {
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// We can't coerce because it is packed in `Wrapper`
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x
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//~^ ERROR lifetime may not live long enough
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}
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fn main() {}
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