mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-24 07:44:10 +00:00
28 lines
695 B
Rust
28 lines
695 B
Rust
//@ run-pass
|
|
|
|
// Example taken from RFC 1238 text
|
|
|
|
// https://github.com/rust-lang/rfcs/blob/master/text/1238-nonparametric-dropck.md
|
|
// #example-of-the-unguarded-escape-hatch
|
|
|
|
#![feature(dropck_eyepatch)]
|
|
use std::cell::Cell;
|
|
|
|
struct Concrete<'a>(#[allow(dead_code)] u32, Cell<Option<&'a Concrete<'a>>>);
|
|
|
|
struct Foo<T> { data: Vec<T> }
|
|
|
|
// Below is the UGEH attribute
|
|
unsafe impl<#[may_dangle] T> Drop for Foo<T> {
|
|
fn drop(&mut self) { }
|
|
}
|
|
|
|
fn main() {
|
|
let mut foo = Foo { data: Vec::new() };
|
|
foo.data.push(Concrete(0, Cell::new(None)));
|
|
foo.data.push(Concrete(0, Cell::new(None)));
|
|
|
|
foo.data[0].1.set(Some(&foo.data[1]));
|
|
foo.data[1].1.set(Some(&foo.data[0]));
|
|
}
|