31 lines
1.1 KiB
Rust
31 lines
1.1 KiB
Rust
// Copyright 2012 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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#[derive(PartialEq, Debug)]
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pub struct Partial<T> { x: T, y: T }
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#[derive(PartialEq, Debug)]
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struct S { val: isize }
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impl S { fn new(v: isize) -> S { S { val: v } } }
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impl Drop for S { fn drop(&mut self) { } }
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pub fn f<T, F>((b1, b2): (T, T), mut f: F) -> Partial<T> where F: FnMut(T) -> T {
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let p = Partial { x: b1, y: b2 };
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// Move of `p` is legal even though we are also moving `p.y`; the
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// `..p` moves all fields *except* `p.y` in this context.
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Partial { y: f(p.y), ..p }
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}
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pub fn main() {
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let p = f((S::new(3), S::new(4)), |S { val: z }| S::new(z+1));
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assert_eq!(p, Partial { x: S::new(3), y: S::new(5) });
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}
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