Re: type casting tagged types in the wrong direction

[dewar@cs.nyu.edu (Robert Dewar)]

So the one at ftp://cs.nyu.edu/pub/gnat/ is validated?  The ones you
mention above are commercially available from SGI.

  The validation of GNAT was carried out by Ada Core Technologies, and
  the validation certificates are jointly held by SGI and ACT. I believe
  the validated version is not yet actually available from SGI (it is
  in beta test now), but it is available from us. Not by FTP from some
  public site we have no control over (who knows what bits you are getting
  there, we cannot take formal responsibility for versions of GNAT you get
  from some public FTP directory). However, we can definitely supply you
  with an officially validated version today for the SGI if you want one.

  A bug like this is undoubtedly host/target independent, so it is
  undoubtedly present in the validated version.


Perhaps I am a virgin, but I don't see how a compiler passes validation
without properly giving an error message.  Tucker Taft mentioned
something about needing a new ACVC test.  Sounds to me like the
validation suite ain't quite up to snuff yet.  Of course, that's true
anyway since there is no such thing yet as full validation anyway.
There won't be until a year from now (ACVC 2.1 is what is needed for
full validation).

  If you think that ANY testing guarantees 100% freedom from all bugs,
  you are indeed a virgin! No test suite can possibly make this guarantee.
  Even if the number of tests were multiplied by 100, there could still
  be errors, and indeed compilers are pretty complex programs, and
  ensuring that a compiler for a language like C++ or Ada is 100%
  error free is beyond the state of the art.

  What Tuck suggested is that this particular error seems like something
  that should be checked by the ACVC suite. This is true, and in fact
  2.1 contains such a test, but note again that if you think that "full
  validation" means that all possible tests are present, you are much
  mistaken.


What do you mean by "now"?  It is not fixed in 3.03 (which is what I am
running), and according to the above mentioned ftp site this is still
the latest version, so it is most certainly not fixed "now".

  I mean that it is fixed in version 3.04, which is already being run by
  some of our customers. Version 3.04 will be publically released some
  time in the future. I don't know when this bug was fixed -- a while
  ago it seems, but it is certainly possible that one or more versions
  of 3.03 may exhibit this bug.