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32 lines
812 B
Rust
32 lines
812 B
Rust
// edition:2018
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// Test that a feature gate is needed to use `impl Trait` as the
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// return type of an async.
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trait Trait<'a> { }
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impl<T> Trait<'_> for T { }
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// Fails to recognize that both 'a and 'b are mentioned and should thus be accepted
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async fn async_ret_impl_trait3<'a, 'b>(a: &'a u8, b: &'b u8) -> impl Trait<'a> + 'b {
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//~^ ERROR lifetime may not live long enough
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(a, b)
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}
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// Only `'a` permitted in return type, not `'b`.
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async fn async_ret_impl_trait1<'a, 'b>(a: &'a u8, b: &'b u8) -> impl Trait<'a> {
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//~^ ERROR captures lifetime that does not appear in bounds
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(a, b)
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}
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// As above, but `'b: 'a`, so return type can be inferred to `(&'a u8,
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// &'a u8)`.
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async fn async_ret_impl_trait2<'a, 'b>(a: &'a u8, b: &'b u8) -> impl Trait<'a>
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where
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'b: 'a,
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{
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(a, b)
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}
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fn main() {
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}
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