Hello, I have a class class HasIniConfig where getConfig ... a kind using DataKind data ProjectionType = TypeA | TypeB ... I would like to create instance for each 'TypeX But when I try to write an instance I get this error src/Hkl/Binoculars/Projections/QCustom.hs:195:23: error: • Expected a type, but ‘'QCustomProjection’ has kind ‘ProjectionType’ • In the first argument of ‘HasIniConfig’, namely ‘'QCustomProjection’ In the instance declaration for ‘HasIniConfig 'QCustomProjection’ | 195 | instance HasIniConfig 'QCustomProjection where | ^^^^^^^^^^^^^^^^^^ I should add class HasIniConfig (a :: ProjectionType) where But in that cas I can not create instance for other type, and I need to :) I would be glade if someone could explain how to all this. Thanks Frederic