Assertion violation error at mpz.cpp

[aqjune]

I see ASSERTION VIOLATION error when running with TRACE=true.

$ cat a.smt2
(declare-fun ty_%a () (_ BitVec 2))                                                                                                                                                                             
(declare-fun undef!1 () (_ FloatingPoint 8 24))                                                                                                                                                                 
(assert (and (forall ((undef!0 (_ FloatingPoint 8 24)))                                                                                                                                                         
       (let ((a!1 (fp.isNaN (fp.add roundNearestTiesToEven                                      
                                    ((_ to_fp 8 24) (fp.to_ieee_bv undef!0))                                                                                                                                    
                                    (_ +zero 8 24))))                                                                                                                                                           
             (a!2 (= (fp.add roundNearestTiesToEven                                                     
                             ((_ to_fp 8 24) (fp.to_ieee_bv undef!0))                                
                             (_ +zero 8 24))                                                                                                                                                                    
                     (fp.add roundNearestTiesToEven                                                     
                             ((_ to_fp 8 24) (fp.to_ieee_bv undef!1))
                             (_ +zero 8 24)))))
         (not (or a!1 a!2))))
     (= ty_%a #b01)))   
(check-sat)
$ z3 a.smt2 TRACE=true
ASSERTION VIOLATION
File: ../src/util/mpz.cpp
Line: 1791
numBits <= sizeof(unsigned)*8
(C)ontinue, (A)bort, (S)top, (T)hrow exception, Invoke (G)DB
^C