// Regression test for #31567: cached results of projections were // causing region relations not to be enforced at all the places where // they have to be enforced. struct VecWrapper<'a>(&'a mut S); struct S(Box); fn get_dangling<'a>(v: VecWrapper<'a>) -> &'a u32 { let s_inner: &'a S = &*v.0; //~ ERROR borrow may still be in use when destructor runs [E0713] &s_inner.0 } impl<'a> Drop for VecWrapper<'a> { fn drop(&mut self) { *self.0 = S(Box::new(0)); } } fn main() { let mut s = S(Box::new(11)); let vw = VecWrapper(&mut s); let dangling = get_dangling(vw); println!("{}", dangling); }