| // Copyright 2017 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // run-pass |
| // Test when destructors run in a for loop. The intention is |
| // that the value for each iteration is dropped *after* the loop |
| // body has executed. This is true even when the value is assigned |
| // to a `_` pattern (and hence ignored). |
| |
| use std::cell::Cell; |
| |
| struct Flag<'a>(&'a Cell<bool>); |
| |
| impl<'a> Drop for Flag<'a> { |
| fn drop(&mut self) { |
| self.0.set(false) |
| } |
| } |
| |
| fn main() { |
| let alive2 = Cell::new(true); |
| for _i in std::iter::once(Flag(&alive2)) { |
| // The Flag value should be alive in the for loop body |
| assert_eq!(alive2.get(), true); |
| } |
| // The Flag value should be dead outside of the loop |
| assert_eq!(alive2.get(), false); |
| |
| let alive = Cell::new(true); |
| for _ in std::iter::once(Flag(&alive)) { |
| // The Flag value should be alive in the for loop body even if it wasn't |
| // bound by the for loop |
| assert_eq!(alive.get(), true); |
| } |
| // The Flag value should be dead outside of the loop |
| assert_eq!(alive.get(), false); |
| } |