Leary zoil: Let me quote myself: "There is a kind-of workaround for "Read"-like cases by taking a singleton as a constraint and matching on it, but then you have to supply that singleton constraint everywhere instead." Expand trickard and one other left, @irc_libera.chat_trickard_:kf8nh.com joined Leary However, if you have multiple such cases, the same singleton constraint will cover all of them. Further, these constraints often useful in and of themselves. are often*