// Reject mixing cyclic structure and Drop when using TypedArena. // // (Compare against dropck-vec-cycle-checked.rs) // // (Also compare against ui-fulldeps/dropck-tarena-unsound-drop.rs, // which is a reduction of this code to more directly show the reason // for the error message we see here.) #![feature(rustc_private)] extern crate rustc_arena; use rustc_arena::TypedArena; 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<'a>(arena: &'a TypedArena<C<'a>>) { let c1 = arena.alloc(C::new()); let c2 = arena.alloc(C::new()); let c3 = arena.alloc(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)); c1.v[1].v.set(Some(c3)); c2.v[0].v.set(Some(c2)); c2.v[1].v.set(Some(c3)); c3.v[0].v.set(Some(c1)); c3.v[1].v.set(Some(c2)); } fn main() { let arena = TypedArena::default(); f(&arena); } //~^ ERROR `arena` does not live long enough