215d66b998
It turns out that this *can* happen after all, if the region is only used in projections from the input types.
35 lines
1,018 B
Rust
35 lines
1,018 B
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Regression test for #47511: anonymous lifetimes can appear
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// unconstrained in a return type, but only if they appear just once
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// in the input, as the input to a projection.
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fn f(_: X) -> X {
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//~^ ERROR return type references an anonymous lifetime
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unimplemented!()
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}
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fn g<'a>(_: X<'a>) -> X<'a> {
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//~^ ERROR return type references lifetime `'a`, which is not constrained
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unimplemented!()
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}
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type X<'a> = <&'a () as Trait>::Value;
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trait Trait {
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type Value;
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}
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impl<'a> Trait for &'a () {
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type Value = ();
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}
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fn main() {}
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