invalid model on a QF_NIA instance

[zhendongsu]

Commit: 97b66d1
OS: Ubuntu 18.04

[671] % z3release model_validate=true small.smt2
sat
(error "line 13 column 10: an invalid model was generated")
(
  (define-fun e () Int
    0)
  (define-fun g () Int
    17)
  (define-fun d () Int
    28)
  (define-fun f () Int
    0)
  (define-fun a () Int
    1)
  (define-fun b () Int
    27)
  (define-fun c () Bool
    false)
)
[672] % cat small.smt2
(declare-fun a () Int)
(declare-fun b () Int)
(declare-fun c () Bool)
(declare-fun d () Int)
(declare-fun e () Int)
(declare-fun f () Int)
(declare-fun g () Int)
(assert (<= 0 a 18))
(assert (<= 0 e 1))
(assert (<= 0 f 1 b 32 (* d g)))
(assert (= (- d a b) 0 (- a 1 (* 3 f))))
(assert (or c (< a (+ e (* 3 f)))))
(check-sat)
(get-model)