src/test/run-pass-valgrind/cast-enum-with-dtor.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 // ignore-pretty : (#23623) problems when  ending with // comments
  12
  13 // no-prefer-dynamic
  14
  15 #![allow(dead_code)]
  16 #![feature(const_fn, rustc_attrs)]
  17
  18 // check dtor calling order when casting enums.
  19
  20 use std::sync::atomic;
  21 use std::sync::atomic::Ordering;
  22 use std::mem;
  23
  24 enum E {
  25     A = 0,
  26     B = 1,
  27     C = 2
  28 }
  29
  30 static FLAG: atomic::AtomicUsize = atomic::AtomicUsize::new(0);
  31
  32 impl Drop for E {
  33     fn drop(&mut self) {
  34         // avoid dtor loop
  35         unsafe { mem::forget(mem::replace(self, E::B)) };
  36
  37         FLAG.store(FLAG.load(Ordering::SeqCst)+1, Ordering::SeqCst);
  38     }
  39 }
  40
  41 #[rustc_no_mir] // FIXME #27840 MIR miscompiles this.
  42 fn main() {
  43     assert_eq!(FLAG.load(Ordering::SeqCst), 0);
  44     {
  45         let e = E::C;
  46         assert_eq!(e as u32, 2);
  47         assert_eq!(FLAG.load(Ordering::SeqCst), 0);
  48     }
  49     assert_eq!(FLAG.load(Ordering::SeqCst), 1);
  50 }