isExoticPropTy :: ObjType -> Bool
isExoticPropTy (PropTy (Open propHyps PropConst)) =
               any (not . isClosedTermTy . bindTy) propHyps
isExoticPropTy :: ObjType -> Bool
isExoticPropTy (PropTy (Open propHyps PropConst)) =
               any (not . isClosedTermTy . bindTy) propHyps
isExoticPropTy (PropTy (Open propHyps PropConst)) =
               any (not . isClosedTermTy . bindTy) propHyps