43 lines
1.1 KiB
Rust
43 lines
1.1 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 the Fn trait hierarchy rules permit
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// FnMut or FnOnce to be used where FnMut is implemented.
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#![feature(unboxed_closures, fn_traits)]
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struct S;
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impl FnMut<(i32,)> for S {
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extern "rust-call" fn call_mut(&mut self, (x,): (i32,)) -> i32 {
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x * x
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}
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}
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impl FnOnce<(i32,)> for S {
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type Output = i32;
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extern "rust-call" fn call_once(mut self, args: (i32,)) -> i32 { self.call_mut(args) }
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}
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fn call_it_mut<F:FnMut(i32)->i32>(f: &mut F, x: i32) -> i32 {
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f(x)
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}
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fn call_it_once<F:FnOnce(i32)->i32>(f: F, x: i32) -> i32 {
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f(x)
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}
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fn main() {
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let y = call_it_mut(&mut S, 22);
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let z = call_it_once(S, 22);
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assert_eq!(y, z);
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}
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