src/test/ui/nll/relate_tys/universe-violation.rs

   1 // Test that the NLL `relate_tys` code correctly deduces that a
   2 // function returning either argument CANNOT be upcast to one
   3 // that returns always its first argument.
   4 //
   5 // compile-flags:-Zno-leak-check
   6
   7 #![feature(nll)]
   8
   9 fn make_it() -> fn(&'static u32) -> &'static u32 {
  10     panic!()
  11 }
  12
  13 fn main() {
  14     let a: fn(_) -> _ = make_it();
  15     let b: fn(&u32) -> &u32 = a;
  16     drop(a);
  17 }