Just experimenting with smtlib. I'm not seeing whats wrong with the following...
(set-logic BV)
(declare-fun var1 () (_ BitVec 32)) ; a is a constant
(declare-fun var2 () (_ BitVec 32)) ; a is a constant
(declare-fun var3 () (_ BitVec 32)) ; a is a constant
(assert(
(= var1 var2)
and
(= var3 bvsub(var1 var2) )
))
(check-sat)
(get-model)
Running it with z3 and the error is: (error "line 7 column 2: invalid qualified/indexed identifier, '_' or 'as' expected")