error[E0277]: the trait bound `A: Foo` is not satisfied
  --> $DIR/associated-const-type-parameter-arrays-2.rs:27:22
   |
LL |     let _array = [4; <A as Foo>::Y];
   |                      ^^^^^^^^^^^^^ the trait `Foo` is not implemented for `A`
   |
   = help: consider adding a `where A: Foo` bound
note: required by `Foo::Y`
  --> $DIR/associated-const-type-parameter-arrays-2.rs:13:5
   |
LL |     const Y: usize;
   |     ^^^^^^^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.