error[E0038]: the trait `Foo` is not dyn compatible
  --> $DIR/gat-in-trait-path.rs:22:17
   |
LL | fn f(_arg : Box<dyn for<'a> Foo<A<'a> = &'a ()>>) {}
   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `Foo` is not dyn compatible
   |
note: for a trait to be dyn compatible it needs to allow building a vtable
      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
  --> $DIR/gat-in-trait-path.rs:6:10
   |
LL | trait Foo {
   |       --- this trait is not dyn compatible...
LL |     type A<'a> where Self: 'a;
   |          ^ ...because it contains the generic associated type `A`
   = help: consider moving `A` to another trait

error[E0038]: the trait `Foo` is not dyn compatible
  --> $DIR/gat-in-trait-path.rs:27:5
   |
LL |   f(Box::new(foo));
   |     ^^^^^^^^^^^^^ `Foo` is not dyn compatible
   |
note: for a trait to be dyn compatible it needs to allow building a vtable
      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
  --> $DIR/gat-in-trait-path.rs:6:10
   |
LL | trait Foo {
   |       --- this trait is not dyn compatible...
LL |     type A<'a> where Self: 'a;
   |          ^ ...because it contains the generic associated type `A`
   = help: consider moving `A` to another trait

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0038`.