28 lines
817 B
Rust
28 lines
817 B
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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// pretty-expanded FIXME #23616
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#![allow(unknown_features)]
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#![feature(box_syntax)]
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trait double {
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fn double(self: Box<Self>) -> usize;
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}
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impl double for Box<usize> {
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fn double(self: Box<Box<usize>>) -> usize { **self * 2 }
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}
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pub fn main() {
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let x: Box<Box<Box<Box<Box<_>>>>> = box box box box box 3;
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assert_eq!(x.double(), 6);
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}
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