rust/tests/ui/regions/regions-trait-object-1.rs
2024-02-16 20:02:50 +00:00

36 lines
667 B
Rust

//@ run-pass
// This is a regression test for something that only came up while
// attempting to bootstrap librustc_ast; it is adapted from
// `rustc_ast::ext::tt::generic_extension`.
pub struct E<'a> {
pub f: &'a u8,
}
impl<'b> E<'b> {
pub fn m(&self) -> &'b u8 { self.f }
}
pub struct P<'c> {
pub g: &'c u8,
}
pub trait M {
fn n(&self) -> u8;
}
impl<'d> M for P<'d> {
fn n(&self) -> u8 { *self.g }
}
fn extension<'e>(x: &'e E<'e>) -> Box<dyn M+'e> {
loop {
let p = P { g: x.m() };
return Box::new(p) as Box<dyn M+'e>;
}
}
fn main() {
let w = E { f: &10 };
let o = extension(&w);
assert_eq!(o.n(), 10);
}