src/test/ui/nll/issue-57642-higher-ranked-subtype.rs

   1 // Regression test for issue #57642
   2 // Tests that we reject a bad higher-ranked subtype
   3
   4 trait X {
   5     type G;
   6     fn make_g() -> Self::G;
   7 }
   8
   9 impl<'a> X for fn(&'a ()) {
  10     type G = &'a ();
  11
  12     fn make_g() -> Self::G {
  13         &()
  14     }
  15 }
  16
  17 trait Y {
  18     type F;
  19     fn make_f() -> Self::F;
  20 }
  21
  22 impl<T> Y for fn(T) {
  23     type F = fn(T);
  24
  25     fn make_f() -> Self::F {
  26         |_| {}
  27     }
  28 }
  29
  30 fn higher_ranked_region_has_lost_its_binder() {
  31     let x = <fn (&())>::make_g(); //~ ERROR the function
  32 }
  33
  34 fn magical() {
  35     let x = <fn (&())>::make_f(); //~ ERROR no function
  36 }
  37
  38 fn main() {}