error[E0277]: the trait bound `X: std::cmp::Ord` is not satisfied
  --> $DIR/issue-20162.rs:5:7
   |
LL |     b.sort();
   |       ^^^^ the trait `std::cmp::Ord` is not implemented for `X`

error: aborting due to previous error

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