error[E0091]: type parameter `T` is unused --> $DIR/E0091.rs:1:10 | LL | type Foo = u32; | ^ unused type parameter error[E0091]: type parameter `B` is unused --> $DIR/E0091.rs:2:14 | LL | type Foo2 = Box; | ^ unused type parameter error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0091`.