+-- This nasty little function tests for whether a RdrName was
+-- constructed by the above process. It's used only for filtering
+-- out duff error messages. Maybe there's a tidier way of doing this
+-- but I can't work up the energy to find it.
+
+isClassDataConRdrName rdr_name
+ = case rdrNameOcc rdr_name of
+ TCOcc s -> case _UNPK_ s of
+ ':' : c : _ -> isUpper c
+ other -> False
+ other -> False