rust/tests/ui/span/dropck_arr_cycle_checked.rs
2023-01-11 09:32:08 +00:00

107 lines
2.1 KiB
Rust

// Reject mixing cyclic structure and Drop when using fixed length
// arrays.
//
// (Compare against ui/span/dropck_vec_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 B<'a> {
id: Id,
a: [CheckId<Cell<Option<&'a B<'a>>>>; 2]
}
impl<'a> HasId for Cell<Option<&'a B<'a>>> {
fn count(&self) -> usize {
match self.get() {
None => 1,
Some(b) => b.id.count(),
}
}
}
impl<'a> B<'a> {
fn new() -> B<'a> {
B { id: Id::new(), a: [CheckId(Cell::new(None)), CheckId(Cell::new(None))] }
}
}
fn f() {
let (b1, b2, b3);
b1 = B::new();
b2 = B::new();
b3 = B::new();
b1.a[0].v.set(Some(&b2));
//~^ ERROR `b2` does not live long enough
b1.a[1].v.set(Some(&b3));
//~^ ERROR `b3` does not live long enough
b2.a[0].v.set(Some(&b2));
b2.a[1].v.set(Some(&b3));
b3.a[0].v.set(Some(&b1));
//~^ ERROR `b1` does not live long enough
b3.a[1].v.set(Some(&b2));
}
fn main() {
f();
}