| //@ 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); |
| } |
