35 lines
1.0 KiB
Rust
35 lines
1.0 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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enum Either<T, U> { Left(T), Right(U) }
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struct X(Either<(usize,usize), fn()>);
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impl X {
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pub fn with<F>(&self, blk: F) where F: FnOnce(&Either<(usize, usize), fn()>) {
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let X(ref e) = *self;
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blk(e)
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}
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}
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fn main() {
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let mut x = X(Either::Right(main as fn()));
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(&mut x).with(
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|opt| { //~ ERROR cannot borrow `x` as mutable more than once at a time
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match opt {
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&Either::Right(ref f) => {
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x = X(Either::Left((0, 0)));
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(*f)()
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},
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_ => panic!()
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}
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})
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}
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