import Bag ( Bag, emptyBag, unionBags, listToBag )
import Class ( classKey, Class )
-import ErrUtils ( ErrMsg, dumpIfSet )
+import ErrUtils ( dumpIfSet, Message )
import MkId ( mkDictFunId )
import Id ( mkVanillaId )
import DataCon ( dataConArgTys, isNullaryDataCon )
\end{code}
\begin{code}
-derivingThingErr :: FAST_STRING -> FAST_STRING -> TyCon -> ErrMsg
+derivingThingErr :: FAST_STRING -> FAST_STRING -> TyCon -> Message
derivingThingErr thing why tycon
= hang (hsep [ptext SLIT("Can't make a derived instance of"), ptext thing])