// Issue #26656: Verify that trait objects cannot bypass dropck. // Using this instead of Fn etc. to take HRTB out of the equation. trait Trigger { fn fire(&self, b: &mut B); } impl Trigger for () { fn fire(&self, b: &mut B) { b.push(); } } // Still unsound Zook trait Button { fn push(&self); } struct Zook { button: B, trigger: Box+'static> } impl Drop for Zook { 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