src/test/ui/generic-associated-types/issue-87258_a.rs

   1 #![feature(type_alias_impl_trait)]
   2 #![feature(generic_associated_types)]
   3
   4 // See https://github.com/rust-lang/rust/issues/87258#issuecomment-883293367
   5
   6 trait Trait1 {}
   7
   8 struct Struct<'b>(&'b ());
   9
  10 impl<'d> Trait1 for Struct<'d> {}
  11
  12 pub trait Trait2 {
  13     type FooFuture<'a>: Trait1;
  14     fn foo<'a>() -> Self::FooFuture<'a>;
  15 }
  16
  17 impl<'c, S: Trait2> Trait2 for &'c mut S {
  18     type FooFuture<'a> = impl Trait1;
  19     //~^ ERROR unconstrained opaque type
  20     fn foo<'a>() -> Self::FooFuture<'a> {
  21         Struct(unimplemented!())
  22     }
  23 }
  24
  25 fn main() {}