44 lines
1.1 KiB
Rust
44 lines
1.1 KiB
Rust
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// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![feature(conservative_impl_trait, specialization)]
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trait Foo: std::fmt::Debug + Eq {}
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impl<T: std::fmt::Debug + Eq> Foo for T {}
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fn hide<T: Foo>(x: T) -> impl Foo {
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x
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}
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trait Leak<T>: Sized {
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fn leak(self) -> T;
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}
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impl<T, U> Leak<T> for U {
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default fn leak(self) -> T { panic!("type mismatch") }
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}
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impl<T> Leak<T> for T {
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fn leak(self) -> T { self }
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}
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fn lucky_seven() -> impl Fn(usize) -> u8 {
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let a = [1, 2, 3, 4, 5, 6, 7];
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move |i| a[i]
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}
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fn main() {
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assert_eq!(hide(42), hide(42));
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assert_eq!(std::mem::size_of_val(&hide([0_u8; 5])), 5);
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assert_eq!(std::mem::size_of_val(&lucky_seven()), 7);
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assert_eq!(Leak::<i32>::leak(hide(5_i32)), 5_i32);
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}
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