--- Naked PredTys don't usually show up, but they can as a result of
--- {-# SPECIALISE instance Ord Char #-}
--- The Right Thing would be to fix the way that SPECIALISE instance pragmas
--- are handled, but the quick thing is just to permit PredTys here.
-check_type _ _ (PredTy sty)
- = do { dflags <- getDOpts
- ; check_pred_ty dflags TypeCtxt sty }
+-- Naked PredTys should, I think, have been rejected before now
+check_type _ _ ty@(PredTy {})
+ = failWithTc (text "Predicate used as a type:" <+> ppr ty)