+pprPred (EqPred ty1 ty2) = pprEqPred (ty1,ty2)
+
+pprEqPred :: (Type,Type) -> SDoc
+pprEqPred (ty1,ty2) = sep [ ppr_type FunPrec ty1
+ , nest 2 (ptext (sLit "~"))
+ , ppr_type FunPrec ty2]
+ -- Precedence looks like (->) so that we get
+ -- Maybe a ~ Bool
+ -- (a->a) ~ Bool
+ -- Note parens on the latter!
+