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#![feature(thin_box)]
// run-pass
use std::boxed::ThinBox;
use std::error::Error;
use std::ops::Deref;
use std::fmt;
fn main() {
let expected = "Foo error!";
let mut dropped = false;
{
let foo = Foo(expected, &mut dropped);
let a: ThinBox<dyn Error> = ThinBox::new_unsize(foo);
let a = a.deref();
let msg = a.to_string();
assert_eq!(expected, msg);
}
assert!(dropped);
}
#[derive(Debug)]
#[repr(align(1024))]
struct Foo<'a>(&'static str, &'a mut bool);
impl Drop for Foo<'_> {
fn drop(&mut self) {
*self.1 = true;
}
}
impl fmt::Display for Foo<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.0)
}
}
impl Error for Foo<'_> {}
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