; EXPECT: unsat
; COMMAND-LINE: --lang=sygus2 --sygus-out=status
(set-logic SLIA)
(synth-fun f ((x String)) String
((ntString String) (ntStringConst String))

((ntString String (x "" (str.++ ntStringConst ntString ntString)))

(ntStringConst String ("a" "b" " "))

))

; can be solved with concat PBE strategy, although we currently are not (issue #1259)
; regardless, this is small enough to solve quickly
(constraint (= (f "def") "ab def"))

(check-synth)