src/test/run-pass/issue-21486.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 #21486: Make sure that all structures are dropped, even when
  12 // created via FRU and control-flow breaks in the middle of
  13 // construction.
  14
  15 #![feature(const_fn)]
  16
  17 use std::sync::atomic::{Ordering, AtomicUsize};
  18
  19 #[derive(Debug)]
  20 struct Noisy(u8);
  21 impl Drop for Noisy {
  22     fn drop(&mut self) {
  23         // println!("splat #{}", self.0);
  24         event(self.0);
  25     }
  26 }
  27
  28 #[allow(dead_code)]
  29 #[derive(Debug)]
  30 struct Foo { n0: Noisy, n1: Noisy }
  31 impl Foo {
  32     fn vals(&self) -> (u8, u8) { (self.n0.0, self.n1.0) }
  33 }
  34
  35 fn leak_1_ret() -> Foo {
  36     let _old_foo = Foo { n0: Noisy(1), n1: Noisy(2) };
  37     Foo { n0: { return Foo { n0: Noisy(3), n1: Noisy(4) } },
  38           .._old_foo
  39     };
  40 }
  41
  42 fn leak_2_ret() -> Foo {
  43     let _old_foo = Foo { n0: Noisy(1), n1: Noisy(2) };
  44     Foo { n1: { return Foo { n0: Noisy(3), n1: Noisy(4) } },
  45           .._old_foo
  46     };
  47 }
  48
  49 // In this case, the control flow break happens *before* we construct
  50 // `Foo(Noisy(1),Noisy(2))`, so there should be no record of it in the
  51 // event log.
  52 fn leak_3_ret() -> Foo {
  53     let _old_foo = || Foo { n0: Noisy(1), n1: Noisy(2) };
  54     Foo { n1: { return Foo { n0: Noisy(3), n1: Noisy(4) } },
  55           .._old_foo()
  56     };
  57 }
  58
  59 pub fn main() {
  60     reset_log();
  61     assert_eq!(leak_1_ret().vals(), (3,4));
  62     assert_eq!(0x01_02_03_04, event_log());
  63
  64     reset_log();
  65     assert_eq!(leak_2_ret().vals(), (3,4));
  66     assert_eq!(0x01_02_03_04, event_log());
  67
  68     reset_log();
  69     assert_eq!(leak_3_ret().vals(), (3,4));
  70     assert_eq!(0x03_04, event_log());
  71 }
  72
  73 static LOG: AtomicUsize = AtomicUsize::new(0);
  74
  75 fn reset_log() {
  76     LOG.store(0, Ordering::SeqCst);
  77 }
  78
  79 fn event_log() -> usize {
  80     LOG.load(Ordering::SeqCst)
  81 }
  82
  83 fn event(tag: u8) {
  84     let old_log = LOG.load(Ordering::SeqCst);
  85     let new_log = (old_log << 8) + tag as usize;
  86     LOG.store(new_log, Ordering::SeqCst);
  87 }