error[E0091]: type parameter `T` is unused
  --> $DIR/E0091.rs:1:10
   |
LL | type Foo<T> = u32;
   |          ^ unused type parameter

error[E0091]: type parameter `B` is unused
  --> $DIR/E0091.rs:2:14
   |
LL | type Foo2<A, B> = Box<A>;
   |              ^ unused type parameter

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0091`.