mkInstTyTcOcc :: Int -- ^ DFun Index
-> OccName -- ^ Family name, e.g. @Map@
-> OccName -- ^ Nice unique version, e.g. @:R23Map@
mkInstTyTcOcc :: Int -- ^ DFun Index
-> OccName -- ^ Family name, e.g. @Map@
-> OccName -- ^ Nice unique version, e.g. @:R23Map@