rnBindGroups :: [HsBindGroup RdrName] -> RnM ([HsBindGroup Name], DefUses)
-- This version assumes that the binders are already in scope
-- It's used only in 'mdo'
-rnBindGropus []
+rnBindGroups []
= returnM ([], emptyDUs)
rnBindGroups [HsBindGroup bind sigs _]
= rnBinds NotTopLevel bind sigs