43 lines
1.2 KiB
Rust
43 lines
1.2 KiB
Rust
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// Copyright 2017 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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use std::cell::RefCell;
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pub struct DropLogger<'a> {
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id: usize,
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log: &'a RefCell<Vec<usize>>
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}
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impl<'a> Drop for DropLogger<'a> {
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fn drop(&mut self) {
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self.log.borrow_mut().push(self.id);
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}
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}
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fn main() {
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let log = RefCell::new(vec![]);
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let d = |id| DropLogger { id: id, log: &log };
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let get = || -> Vec<_> {
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let mut m = log.borrow_mut();
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let n = m.drain(..);
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n.collect()
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};
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{
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let _x = (d(0), &d(1), d(2), &d(3));
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// all borrows are extended - nothing has been dropped yet
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assert_eq!(get(), vec![]);
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}
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// in a let-statement, extended lvalues are dropped
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// *after* the let result (tho they have the same scope
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// as far as scope-based borrowck goes).
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assert_eq!(get(), vec![0, 2, 3, 1]);
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}
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