src/test/compile-fail/dropck_vec_cycle_checked.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 // Reject mixing cyclic structure and Drop when using Vec.
  12 //
  13 // (Compare against compile-fail/dropck_arr_cycle_checked.rs)
  14
  15 #![feature(const_fn)]
  16
  17 use std::cell::Cell;
  18 use id::Id;
  19
  20 mod s {
  21     #![allow(unstable)]
  22     use std::sync::atomic::{AtomicUsize, Ordering};
  23
  24     static S_COUNT: AtomicUsize = AtomicUsize::new(0);
  25
  26     pub fn next_count() -> usize {
  27         S_COUNT.fetch_add(1, Ordering::SeqCst) + 1
  28     }
  29 }
  30
  31 mod id {
  32     use s;
  33     #[derive(Debug)]
  34     pub struct Id {
  35         orig_count: usize,
  36         count: usize,
  37     }
  38
  39     impl Id {
  40         pub fn new() -> Id {
  41             let c = s::next_count();
  42             println!("building Id {}", c);
  43             Id { orig_count: c, count: c }
  44         }
  45         pub fn count(&self) -> usize {
  46             println!("Id::count on {} returns {}", self.orig_count, self.count);
  47             self.count
  48         }
  49     }
  50
  51     impl Drop for Id {
  52         fn drop(&mut self) {
  53             println!("dropping Id {}", self.count);
  54             self.count = 0;
  55         }
  56     }
  57 }
  58
  59 trait HasId {
  60     fn count(&self) -> usize;
  61 }
  62
  63 #[derive(Debug)]
  64 struct CheckId<T:HasId> {
  65     v: T
  66 }
  67
  68 #[allow(non_snake_case)]
  69 fn CheckId<T:HasId>(t: T) -> CheckId<T> { CheckId{ v: t } }
  70
  71 impl<T:HasId> Drop for CheckId<T> {
  72     fn drop(&mut self) {
  73         assert!(self.v.count() > 0);
  74     }
  75 }
  76
  77 #[derive(Debug)]
  78 struct C<'a> {
  79     id: Id,
  80     v: Vec<CheckId<Cell<Option<&'a C<'a>>>>>,
  81 }
  82
  83 impl<'a> HasId for Cell<Option<&'a C<'a>>> {
  84     fn count(&self) -> usize {
  85         match self.get() {
  86             None => 1,
  87             Some(c) => c.id.count(),
  88         }
  89     }
  90 }
  91
  92 impl<'a> C<'a> {
  93     fn new() -> C<'a> {
  94         C { id: Id::new(), v: Vec::new() }
  95     }
  96 }
  97
  98 fn f() {
  99     let (mut c1, mut c2, mut c3);
 100     c1 = C::new();
 101     c2 = C::new();
 102     c3 = C::new();
 103
 104     c1.v.push(CheckId(Cell::new(None)));
 105     c1.v.push(CheckId(Cell::new(None)));
 106     c2.v.push(CheckId(Cell::new(None)));
 107     c2.v.push(CheckId(Cell::new(None)));
 108     c3.v.push(CheckId(Cell::new(None)));
 109     c3.v.push(CheckId(Cell::new(None)));
 110
 111     c1.v[0].v.set(Some(&c2)); //~ ERROR `c2` does not live long enough
 112     c1.v[1].v.set(Some(&c3)); //~ ERROR `c3` does not live long enough
 113     c2.v[0].v.set(Some(&c2)); //~ ERROR `c2` does not live long enough
 114     c2.v[1].v.set(Some(&c3)); //~ ERROR `c3` does not live long enough
 115     c3.v[0].v.set(Some(&c1)); //~ ERROR `c1` does not live long enough
 116     c3.v[1].v.set(Some(&c2)); //~ ERROR `c2` does not live long enough
 117 }
 118
 119 fn main() {
 120     f();
 121 }