Parse successful. sign: set1 body: Rec {} sign: set1 body: Sum {} sign: Rec {} body: {||} sign: set1 body: Sum {False: Rec {}, True: Rec {}} sign: Sum {False: Rec {}, True: Rec {}} body: (@True {||}) sign: Sum {False: Rec {}, True: Rec {}} body: (@False {||}) sign: ((Sum {False: Rec {}} -> Sum {False: Rec {}, True: Rec {}}) -> (Sum {False: Rec {}, True: Rec {}} -> Sum {False: Rec {}, True: Rec {}})) body: (\ (cases {{ True: \ (\ (@False {||})); } or [0])) sign: ((Sum {} -> Sum {False: Rec {}, True: Rec {}}) -> (Sum {False: Rec {}} -> Sum {False: Rec {}, True: Rec {}})) body: (\ (cases {{ False: \ (\ (@True {||})); } or [0])) sign: (Sum {False: Rec {}, True: Rec {}} -> Sum {False: Rec {}, True: Rec {}}) body: (\ False => (\ (@True {||})); True => (\ (@False {||})); ) Checkmate, dram!