error[E0401]: can't use type parameters from outer function
  --> $DIR/issue-5997-enum.rs:12:16
   |
LL | fn f<Z>() -> bool {
   |    - - type variable from outer function
   |    |
   |    try adding a local type parameter in this method instead
LL |     enum E { V(Z) }
   |                ^ use of type variable from outer function

error: aborting due to previous error

For more information about this error, try `rustc --explain E0401`.