tests/ui/box/thin_drop.rs

   1 #![feature(thin_box)]
   2 // run-pass
   3 use std::boxed::ThinBox;
   4 use std::error::Error;
   5 use std::ops::Deref;
   6 use std::fmt;
   7
   8 fn main() {
   9     let expected = "Foo error!";
  10     let mut dropped = false;
  11     {
  12         let foo = Foo(expected, &mut dropped);
  13         let a: ThinBox<dyn Error> = ThinBox::new_unsize(foo);
  14         let a = a.deref();
  15         let msg = a.to_string();
  16         assert_eq!(expected, msg);
  17     }
  18     assert!(dropped);
  19 }
  20
  21 #[derive(Debug)]
  22 #[repr(align(1024))]
  23 struct Foo<'a>(&'static str, &'a mut bool);
  24
  25 impl Drop for Foo<'_> {
  26     fn drop(&mut self) {
  27         *self.1 = true;
  28     }
  29 }
  30
  31 impl fmt::Display for Foo<'_> {
  32     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  33         write!(f, "{}", self.0)
  34     }
  35 }
  36
  37 impl Error for Foo<'_> {}