9330bae4bd
impls. This is a [breaking-change] (for gated code) in that when you implement `Fn` (`FnMut`) you must also implement `FnOnce`. This commit demonstrates how to fix it.
42 lines
1.2 KiB
Rust
42 lines
1.2 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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// Tests that unsafe extern fn pointers do not implement any Fn traits.
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#![feature(unboxed_closures)]
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use std::ops::{Fn,FnMut,FnOnce};
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extern "C" fn square(x: &isize) -> isize { (*x) * (*x) }
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fn call_it<F:Fn(&isize)->isize>(_: &F, _: isize) -> isize { 0 }
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fn call_it_mut<F:FnMut(&isize)->isize>(_: &mut F, _: isize) -> isize { 0 }
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fn call_it_once<F:FnOnce(&isize)->isize>(_: F, _: isize) -> isize { 0 }
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fn a() {
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let x = call_it(&square, 22);
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//~^ ERROR not implemented
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//~| ERROR not implemented
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}
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fn b() {
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let y = call_it_mut(&mut square, 22);
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//~^ ERROR not implemented
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//~| ERROR not implemented
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}
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fn c() {
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let z = call_it_once(square, 22);
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//~^ ERROR not implemented
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//~| ERROR not implemented
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}
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fn main() { }
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