error[E0277]: the trait bound `&str: X` is not satisfied
  --> $DIR/issue-86530.rs:16:7
   |
LL |     z(" ");
   |     - ^^^ the trait `X` is not implemented for `&str`
   |     |
   |     required by a bound introduced by this call
   |
note: required by a bound in `z`
  --> $DIR/issue-86530.rs:10:8
   |
LL | fn z<T>(t: T)
   |    - required by a bound in this function
LL | where
LL |     T: X,
   |        ^ required by this bound in `z`

error: aborting due to previous error

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