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// Reject mixing cyclic structure and Drop when using Vec.
//
// (Compare against ui/span/dropck_arr_cycle_checked.rs)
use std::cell::Cell;
use id::Id;
mod s {
use std::sync::atomic::{AtomicUsize, Ordering};
static S_COUNT: AtomicUsize = AtomicUsize::new(0);
pub fn next_count() -> usize {
S_COUNT.fetch_add(1, Ordering::SeqCst) + 1
}
}
mod id {
use s;
#[derive(Debug)]
pub struct Id {
orig_count: usize,
count: usize,
}
impl Id {
pub fn new() -> Id {
let c = s::next_count();
println!("building Id {}", c);
Id { orig_count: c, count: c }
}
pub fn count(&self) -> usize {
println!("Id::count on {} returns {}", self.orig_count, self.count);
self.count
}
}
impl Drop for Id {
fn drop(&mut self) {
println!("dropping Id {}", self.count);
self.count = 0;
}
}
}
trait HasId {
fn count(&self) -> usize;
}
#[derive(Debug)]
struct CheckId<T:HasId> {
v: T
}
#[allow(non_snake_case)]
fn CheckId<T:HasId>(t: T) -> CheckId<T> { CheckId{ v: t } }
impl<T:HasId> Drop for CheckId<T> {
fn drop(&mut self) {
assert!(self.v.count() > 0);
}
}
#[derive(Debug)]
struct C<'a> {
id: Id,
v: Vec<CheckId<Cell<Option<&'a C<'a>>>>>,
}
impl<'a> HasId for Cell<Option<&'a C<'a>>> {
fn count(&self) -> usize {
match self.get() {
None => 1,
Some(c) => c.id.count(),
}
}
}
impl<'a> C<'a> {
fn new() -> C<'a> {
C { id: Id::new(), v: Vec::new() }
}
}
fn f() {
let (mut c1, mut c2, mut c3);
c1 = C::new();
c2 = C::new();
c3 = C::new();
c1.v.push(CheckId(Cell::new(None)));
c1.v.push(CheckId(Cell::new(None)));
c2.v.push(CheckId(Cell::new(None)));
c2.v.push(CheckId(Cell::new(None)));
c3.v.push(CheckId(Cell::new(None)));
c3.v.push(CheckId(Cell::new(None)));
c1.v[0].v.set(Some(&c2));
//~^ ERROR `c2` does not live long enough
c1.v[1].v.set(Some(&c3));
//~^ ERROR `c3` does not live long enough
c2.v[0].v.set(Some(&c2));
c2.v[1].v.set(Some(&c3));
c3.v[0].v.set(Some(&c1));
//~^ ERROR `c1` does not live long enough
c3.v[1].v.set(Some(&c2));
}
fn main() {
f();
}
|
