PyRFLX simplification of Div expressions incomplete

[rssen]

Parsing a message for the below specification results the following error.

AssertionError: unresolved field conditions in Test.Fld_B: 23 / 8 /= 15 / 8, 23 / 8 = 15 / 8

package Test is

   type A is mod 2 ** 8;
   type B is mod 2 ** 8;
   type C is mod 2 ** 8;

   type Test is
      message
         Fld_A : A;
         Fld_B : B
            then Fld_C
               if Message'Last / 8 = Fld_B'Last / 8
            then null
               if Message'Last / 8 /= Fld_B'Last / 8;
         Fld_C : C;
      end message;

end Test;

The error occurs because the simplified() method of expression.Div calling the __floordiv__() method of the Number class does not return the result of the division operation, but instead a new Div object that is similar to the one that the operation was performed on, if the result of the division would not be an integer.

This error can also be observed when parsing a TLS handshake client hello message, where the following portion of the specification results in the assertion error:

Legacy_Compression_Methods : Opaque
    with Size => Legacy_Compression_Methods_Length * 8
    then null
       if Message'Last / 8 = Legacy_Compression_Methods'Last / 8
    then Extensions_Length
       if Message'Last / 8 /= Legacy_Compression_Methods'Last / 8;

[treiher]

This bug has been fixed. The fix will be part of 0.20.0.