error[E0046]: not all trait items implemented, missing: `Output`
  --> $DIR/issue-23827.rs:36:1
   |
LL | impl<C: Component> FnOnce<(C,)> for Prototype {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `Output` in implementation
   |
   = note: `Output` from trait: `type Output;`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0046`.