src/test/ui/generic-associated-types/issue-91139.rs

   1 trait Foo<T> {
   2     type Type<'a>
   3     where
   4         T: 'a;
   5 }
   6
   7 impl<T> Foo<T> for () {
   8     type Type<'a> = ()
   9     where
  10         T: 'a;
  11 }
  12
  13 fn foo<T>() {
  14     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
  15     //~^ ERROR `T` does not live long enough
  16     //~| ERROR `T` does not live long enough
  17     //~| ERROR `T` does not live long enough
  18     //~| ERROR `T` does not live long enough
  19     //~| ERROR `T` does not live long enough
  20     //~| ERROR `T` does not live long enough
  21     //~| ERROR `T` does not live long enough
  22     //~| ERROR `T` does not live long enough
  23     //~| ERROR `T` may not live long enough
  24     //
  25     // FIXME: This error is bogus, but it arises because we try to validate
  26     // that `<() as Foo<T>>::Type<'a>` is valid, which requires proving
  27     // that `T: 'a`. Since `'a` is higher-ranked, this becomes
  28     // `for<'a> T: 'a`, which is not true. Of course, the error is bogus
  29     // because there *ought* to be an implied bound stating that `'a` is
  30     // not any lifetime but specifically
  31     // "some `'a` such that `<() as Foo<T>>::Type<'a>" is valid".
  32 }
  33
  34 pub fn main() {}