; EXPECT: unsat
; COMMAND-LINE: --lang=sygus2 --sygus-si=all --sygus-out=status
(set-logic ALL)

(declare-datatypes ((List 0)) (((cons (head Int) (tail List)) (nil))))

(synth-fun f ((x Int)) List)

(declare-var x Int)

(constraint ((_ is cons) (f x)))
(constraint (= (head (f x)) (+ x 7)))
(check-synth)