31 lines
791 B
Rust
31 lines
791 B
Rust
#![feature(thin_box)]
|
|
//@ run-pass
|
|
use std::boxed::ThinBox;
|
|
use std::error::Error;
|
|
use std::{fmt, mem};
|
|
|
|
fn main() {
|
|
let thin_error: ThinBox<dyn Error> = ThinBox::new_unsize(Foo);
|
|
assert_eq!(mem::size_of::<*const i32>(), mem::size_of_val(&thin_error));
|
|
println!("{:?}", thin_error);
|
|
|
|
let thin = ThinBox::new(42i32);
|
|
assert_eq!(mem::size_of::<*const i32>(), mem::size_of_val(&thin));
|
|
println!("{:?}", thin);
|
|
|
|
let thin_slice = ThinBox::<[i32]>::new_unsize([1, 2, 3, 4]);
|
|
assert_eq!(mem::size_of::<*const i32>(), mem::size_of_val(&thin_slice));
|
|
println!("{:?}", thin_slice);
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
struct Foo;
|
|
|
|
impl fmt::Display for Foo {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
write!(f, "boooo!")
|
|
}
|
|
}
|
|
|
|
impl Error for Foo {}
|