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