import Bag ( Bag, isEmptyBag, unionBags, listToBag )
import Class ( classKey, GenClass, SYN_IE(Class) )
-import ErrUtils ( pprBagOfErrors, addErrLoc, SYN_IE(Error) )
+import ErrUtils ( addErrLoc, SYN_IE(Error) )
import Id ( dataConArgTys, isNullaryDataCon, mkDictFunId )
import PrelInfo ( needsDataDeclCtxtClassKeys )
import Maybes ( maybeToBool )