error[E0401]: can't use generic parameters from outer function
  --> $DIR/issue-5997-struct.rs:2:14
   |
LL | fn f<T>() -> bool {
   |    - - type parameter from outer function
   |    |
   |    try adding a local generic parameter in this method instead
LL |     struct S(T);
   |              ^ use of generic parameter from outer function

error: aborting due to previous error

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