Delaboration of notation with AddMonoidHom

Stream: general

[Daniel Weber]

I've defined

import Mathlib.Algebra.Group.Hom.Defs

class Differential (R : Type*) [AddZeroClass R] where
  deriv : R →+ R

postfix:75 "′" => Differential.deriv

def f (R : Type*) [AddZeroClass R] [Differential R] (a : R) := a′

#print f

If deriv is defined as R → R then it delaborates correctly to a′, but when it's R →+ R f is printed as Differential.deriv a. How can I fix this?