+ $f... Dict-fun identifiers (from inst decls)
+ $dmop Default method for 'op'
+ $pnC n'th superclass selector for class C
+ $wf Worker for functtoin 'f'
+ $sf.. Specialised version of f
+ T:C Tycon for dictionary for class C
+ D:C Data constructor for dictionary for class C
+ NTCo:T Coercion connecting newtype T with its representation type
+ TFCo:R Coercion connecting a data family to its respresentation type R
+
+In encoded form these appear as Zdfxxx etc