src/test/ui/impl-trait/multiple-lifetimes/error-handling.rs

   1 // compile-flags:-Zborrowck=mir
   2
   3 #![feature(member_constraints)]
   4 #![feature(type_alias_impl_trait)]
   5
   6 #[derive(Clone)]
   7 struct CopyIfEq<T, U>(T, U);
   8
   9 impl<T: Copy> Copy for CopyIfEq<T, T> {}
  10
  11 type E<'a, 'b> = impl Sized;
  12
  13 fn foo<'a, 'b, 'c>(x: &'static i32, mut y: &'a i32) -> E<'b, 'c> {
  14     let v = CopyIfEq::<*mut _, *mut _>(&mut { x }, &mut y);
  15
  16     // This assignment requires that `x` and `y` have the same type due to the
  17     // `Copy` impl. The reason why we are using a copy to create a constraint
  18     // is that only borrow checking (not regionck in type checking) enforces
  19     // this bound.
  20     let u = v;
  21     let _: *mut &'a i32 = u.1;
  22     unsafe {
  23         let _: &'b i32 = *u.0;
  24         //~^ ERROR lifetime may not live long enough
  25     }
  26     u.0
  27 }
  28
  29 fn main() {}