37 lines
1.0 KiB
Rust
37 lines
1.0 KiB
Rust
// Copyright 2014 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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// Checks that extern fn pointers implement the full range of Fn traits.
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use std::ops::{Fn,FnMut,FnOnce};
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fn square(x: isize) -> isize { x * x }
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fn call_it<F:Fn(isize)->isize>(f: &F, x: isize) -> isize {
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f(x)
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}
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fn call_it_mut<F:FnMut(isize)->isize>(f: &mut F, x: isize) -> isize {
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f(x)
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}
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fn call_it_once<F:FnOnce(isize)->isize>(f: F, x: isize) -> isize {
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f(x)
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}
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fn main() {
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let x = call_it(&square, 22);
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let y = call_it_mut(&mut square, 22);
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let z = call_it_once(square, 22);
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assert_eq!(x, square(22));
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assert_eq!(y, square(22));
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assert_eq!(z, square(22));
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}
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