mirror of https://github.com/rust-lang/rust
45 lines
907 B
Rust
45 lines
907 B
Rust
// Regression test for #84533.
|
|
|
|
use std::marker::PhantomData;
|
|
|
|
fn foo<'b, 'a>() -> PhantomData<&'b &'a ()> {
|
|
PhantomData
|
|
}
|
|
|
|
fn extend_lifetime<'a, 'b, T: ?Sized>(x: &'a T) -> &'b T {
|
|
let f = foo::<'b, 'a>;
|
|
f.baz(x)
|
|
//~^ ERROR lifetime may not live long enough
|
|
}
|
|
|
|
trait Foo<'a, 'b, T: ?Sized> {
|
|
fn baz(self, s: &'a T) -> &'b T;
|
|
}
|
|
impl<'a, 'b, R, F, T: ?Sized> Foo<'a, 'b, T> for F
|
|
where
|
|
F: Fn() -> R,
|
|
R: ProofForConversion<'a, 'b, T>,
|
|
{
|
|
fn baz(self, s: &'a T) -> &'b T {
|
|
self().convert(s)
|
|
}
|
|
}
|
|
|
|
trait ProofForConversion<'a, 'b, T: ?Sized> {
|
|
fn convert(self, s: &'a T) -> &'b T;
|
|
}
|
|
impl<'a, 'b, T: ?Sized> ProofForConversion<'a, 'b, T> for PhantomData<&'b &'a ()> {
|
|
fn convert(self, s: &'a T) -> &'b T {
|
|
s
|
|
}
|
|
}
|
|
|
|
fn main() {
|
|
let d;
|
|
{
|
|
let x = "Hello World".to_string();
|
|
d = extend_lifetime(&x);
|
|
}
|
|
println!("{}", d);
|
|
}
|