rust/tests/run-pass-valgrind/cleanup-auto-borrow-obj.rs

// This would previously leak the Box<Trait> because we wouldn't
// schedule cleanups when auto borrowing trait objects.
// This program should be valgrind clean.

static mut DROP_RAN: bool = false;

struct Foo;
impl Drop for Foo {
    fn drop(&mut self) {
        unsafe {
            DROP_RAN = true;
        }
    }
}

trait Trait {
    fn dummy(&self) {}
}
impl Trait for Foo {}

pub fn main() {
    {
        let _x: &Trait = &*(Box::new(Foo) as Box<Trait>);
    }
    unsafe {
        assert!(DROP_RAN);
    }
}