PolyFunction implementation restriction on Function subclasses

[Adam-Vandervorst]

Compiler version

3.2.0-RC1

Minimized code

val poly_func: [X] => Int => Seq[X] = ???
val poly_pfunc: [X] => PartialFunction[Int, Seq[X]] = ???

Output

Implementation restriction: polymorphic function types must have a value parameter

Expectation

Polymorphic function types to include subclasses of Function, in case this was a small oversight.
Else, I guess this is a feature request.