[534] % z3 model_validate=true small.smt2
sat
(error "line 4 column 10: an invalid model was generated")
(model 
 (define-fun b () String
  "")
 (define-fun a () String
  "")
)
[535] % 
[535] % cat small.smt2
(declare-fun a () String)
(declare-fun b () String)
(assert (distinct a b))
(check-sat)
(get-model)
[536] %