src/test/ui/span/issue-26656.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // Issue #26656: Verify that trait objects cannot bypass dropck.
  12
  13 // Using this instead of Fn etc. to take HRTB out of the equation.
  14 trait Trigger<B> { fn fire(&self, b: &mut B); }
  15 impl<B: Button> Trigger<B> for () {
  16     fn fire(&self, b: &mut B) {
  17         b.push();
  18     }
  19 }
  20
  21 // Still unsound Zook
  22 trait Button { fn push(&self); }
  23 struct Zook<B> { button: B, trigger: Box<Trigger<B>+'static> }
  24
  25 impl<B> Drop for Zook<B> {
  26     fn drop(&mut self) {
  27         self.trigger.fire(&mut self.button);
  28     }
  29 }
  30
  31 // AND
  32 struct Bomb { usable: bool }
  33 impl Drop for Bomb { fn drop(&mut self) { self.usable = false; } }
  34 impl Bomb { fn activate(&self) { assert!(self.usable) } }
  35
  36 enum B<'a> { HarmlessButton, BigRedButton(&'a Bomb) }
  37 impl<'a> Button for B<'a> {
  38     fn push(&self) {
  39         if let B::BigRedButton(borrowed) = *self {
  40             borrowed.activate();
  41         }
  42     }
  43 }
  44
  45 fn main() {
  46     let (mut zook, ticking);
  47     zook = Zook { button: B::HarmlessButton,
  48                   trigger: Box::new(()) };
  49     ticking = Bomb { usable: true };
  50     zook.button = B::BigRedButton(&ticking);
  51 }
  52 //~^^ ERROR `ticking` does not live long enough