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//@ run-pass
#![feature(specialization)] //~ WARN the feature `specialization` is incomplete
trait Foo: std::fmt::Debug + Eq {}
impl<T: std::fmt::Debug + Eq> Foo for T {}
fn hide<T: Foo>(x: T) -> impl Foo {
x
}
trait Leak<T>: Sized {
fn leak(self) -> T;
}
impl<T, U> Leak<T> for U {
default fn leak(self) -> T { panic!("type mismatch") }
}
impl<T> Leak<T> for T {
fn leak(self) -> T { self }
}
trait CheckIfSend: Sized {
type T: Default;
fn check(self) -> Self::T { Default::default() }
}
impl<T> CheckIfSend for T {
default type T = ();
}
impl<T: Send> CheckIfSend for T {
type T = bool;
}
fn lucky_seven() -> impl Fn(usize) -> u8 {
let a = [1, 2, 3, 4, 5, 6, 7];
move |i| a[i]
}
fn main() {
assert_eq!(hide(42), hide(42));
assert_eq!(std::mem::size_of_val(&hide([0_u8; 5])), 5);
assert_eq!(std::mem::size_of_val(&lucky_seven()), 7);
assert_eq!(Leak::<i32>::leak(hide(5_i32)), 5_i32);
assert_eq!(CheckIfSend::check(hide(0_i32)), false);
}
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