error: any use of this value will cause an error
  --> $DIR/issue-50814-2.rs:14:24
   |
LL |     const BAR: usize = [5, 6, 7][T::BOO];
   |     ----------------   ^^^^^^^^^^^^^^^^^ index out of bounds: the length is 3 but the index is 42
   |
   = note: `#[deny(const_err)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>

error[E0080]: evaluation of `foo::<()>` failed
  --> $DIR/issue-50814-2.rs:19:6
   |
LL |     &<A<T> as Foo<T>>::BAR
   |      ^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors

note: the above error was encountered while instantiating `fn foo::<()>`
  --> $DIR/issue-50814-2.rs:31:22
   |
LL |     println!("{:x}", foo::<()>() as *const usize as usize);
   |                      ^^^^^^^^^^^

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0080`.
Future incompatibility report: Future breakage diagnostic:
error: any use of this value will cause an error
  --> $DIR/issue-50814-2.rs:14:24
   |
LL |     const BAR: usize = [5, 6, 7][T::BOO];
   |     ----------------   ^^^^^^^^^^^^^^^^^ index out of bounds: the length is 3 but the index is 42
   |
   = note: `#[deny(const_err)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>