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// run-pass
// Uncovered during work on new scoping rules for safe destructors
// as an important use case to support properly.
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);
}
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