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