src/test/run-pass/cleanup-rvalue-temp-during-incomplete-alloc.rs

   1 // Copyright 2014 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 // Test cleanup of rvalue temporary that occurs while `box` construction
  12 // is in progress. This scenario revealed a rather terrible bug.  The
  13 // ingredients are:
  14 //
  15 // 1. Partial cleanup of `box` is in scope,
  16 // 2. cleanup of return value from `get_bar()` is in scope,
  17 // 3. do_it() panics.
  18 //
  19 // This led to a bug because `the top-most frame that was to be
  20 // cleaned (which happens to be the partial cleanup of `box`) required
  21 // multiple basic blocks, which led to us dropping part of the cleanup
  22 // from the top-most frame.
  23 //
  24 // It's unclear how likely such a bug is to recur, but it seems like a
  25 // scenario worth testing.
  26
  27 // ignore-emscripten no threads support
  28
  29 #![allow(unknown_features)]
  30 #![feature(box_syntax)]
  31
  32 use std::thread;
  33
  34 enum Conzabble {
  35     Bickwick(Foo)
  36 }
  37
  38 struct Foo { field: Box<usize> }
  39
  40 fn do_it(x: &[usize]) -> Foo {
  41     panic!()
  42 }
  43
  44 fn get_bar(x: usize) -> Vec<usize> { vec![x * 2] }
  45
  46 pub fn fails() {
  47     let x = 2;
  48     let mut y: Vec<Box<_>> = Vec::new();
  49     y.push(box Conzabble::Bickwick(do_it(&get_bar(x))));
  50 }
  51
  52 pub fn main() {
  53     thread::spawn(fails).join();
  54 }