| // Copyright 2015 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. |
| |
| // Issue #26656: Verify that trait objects cannot bypass dropck. |
| |
| // Using this instead of Fn etc. to take HRTB out of the equation. |
| trait Trigger<B> { fn fire(&self, b: &mut B); } |
| impl<B: Button> Trigger<B> for () { |
| fn fire(&self, b: &mut B) { |
| b.push(); |
| } |
| } |
| |
| // Still unsound Zook |
| trait Button { fn push(&self); } |
| struct Zook<B> { button: B, trigger: Box<Trigger<B>+'static> } |
| |
| impl<B> Drop for Zook<B> { |
| fn drop(&mut self) { |
| self.trigger.fire(&mut self.button); |
| } |
| } |
| |
| // AND |
| struct Bomb { usable: bool } |
| impl Drop for Bomb { fn drop(&mut self) { self.usable = false; } } |
| impl Bomb { fn activate(&self) { assert!(self.usable) } } |
| |
| enum B<'a> { HarmlessButton, BigRedButton(&'a Bomb) } |
| impl<'a> Button for B<'a> { |
| fn push(&self) { |
| if let B::BigRedButton(borrowed) = *self { |
| borrowed.activate(); |
| } |
| } |
| } |
| |
| fn main() { |
| let (mut zook, ticking); |
| zook = Zook { button: B::HarmlessButton, |
| trigger: Box::new(()) }; |
| ticking = Bomb { usable: true }; |
| zook.button = B::BigRedButton(&ticking); |
| //~^ ERROR `ticking` does not live long enough |
| } |