+
+-- Both type classes as well as data/newtype family instances imply implicit
+-- type constructors. These implicit type constructors refer to their parent
+-- structure (ie, the class or family from which they derive) using a type of
+-- the following form.
+--
+data AlgTyConParent = -- An ordinary type constructor has no parent.
+ NoParentTyCon
+
+ -- Type constructors representing a class dictionary.
+ | ClassTyCon Class
+
+ -- Type constructors representing an instances of a type
+ -- family.
+ | FamilyTyCon TyCon -- the type family
+ [Type] -- instance types
+ TyCon -- a *coercion* identifying
+ -- the representation type
+ -- with the type instance
+
+data SynTyConRhs
+ = OpenSynTyCon Kind -- Type family: *result* kind given
+ | SynonymTyCon Type -- Mentioning head type vars. Acts as a template for
+ -- the expansion when the tycon is applied to some
+ -- types.