error[E0277]: the trait bound `T: Clone` is not satisfied
  --> $DIR/bounds-are-checked-2.rs:10:5
   |
LL |     t
   |     ^ the trait `Clone` is not implemented for `T`
   |
note: required by a bound in an opaque type
  --> $DIR/bounds-are-checked-2.rs:6:22
   |
LL | pub type X<T> = impl Clone;
   |                      ^^^^^
note: this definition site has more where clauses than the opaque type
  --> $DIR/bounds-are-checked-2.rs:9:1
   |
LL | fn f<T: Clone>(t: T) -> X<T> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: consider restricting type parameter `T` with trait `Clone`
   |
LL | pub type X<T: std::clone::Clone> = impl Clone;
   |             +++++++++++++++++++

error: aborting due to 1 previous error

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