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1 | // Copyright 2016 The Rust Project Developers. See the COPYRIGHT |
2 | // file at the top-level directory of this distribution and at | |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
11 | #![feature(conservative_impl_trait, specialization)] | |
12 | ||
13 | trait Foo: std::fmt::Debug + Eq {} | |
14 | ||
15 | impl<T: std::fmt::Debug + Eq> Foo for T {} | |
16 | ||
17 | fn hide<T: Foo>(x: T) -> impl Foo { | |
18 | x | |
19 | } | |
20 | ||
21 | trait Leak<T>: Sized { | |
22 | fn leak(self) -> T; | |
23 | } | |
24 | impl<T, U> Leak<T> for U { | |
25 | default fn leak(self) -> T { panic!("type mismatch") } | |
26 | } | |
27 | impl<T> Leak<T> for T { | |
28 | fn leak(self) -> T { self } | |
29 | } | |
30 | ||
8bb4bdeb XL |
31 | trait CheckIfSend: Sized { |
32 | type T: Default; | |
33 | fn check(self) -> Self::T { Default::default() } | |
34 | } | |
35 | impl<T> CheckIfSend for T { | |
36 | default type T = (); | |
37 | } | |
38 | impl<T: Send> CheckIfSend for T { | |
39 | type T = bool; | |
40 | } | |
41 | ||
5bcae85e SL |
42 | fn lucky_seven() -> impl Fn(usize) -> u8 { |
43 | let a = [1, 2, 3, 4, 5, 6, 7]; | |
44 | move |i| a[i] | |
45 | } | |
46 | ||
47 | fn main() { | |
48 | assert_eq!(hide(42), hide(42)); | |
49 | ||
50 | assert_eq!(std::mem::size_of_val(&hide([0_u8; 5])), 5); | |
51 | assert_eq!(std::mem::size_of_val(&lucky_seven()), 7); | |
52 | ||
53 | assert_eq!(Leak::<i32>::leak(hide(5_i32)), 5_i32); | |
8bb4bdeb XL |
54 | |
55 | assert_eq!(CheckIfSend::check(hide(0_i32)), false); | |
5bcae85e | 56 | } |