should postconditions be evaluated even if Exception is thrown?

[Brad Roberts]

Walter Bright wrote:
> Andrei Alexandrescu wrote:
>> An exception (not an Error) is an expected and documented outcome of a
>> function. After having listened to those endless Boeing stories,
>> please listen to this one :o). Contract Programming covers the
>> correctness of a program, and exceptions are correct behavior. By your
>> very Boeing stories that I stoically endured, it seems like the
>> logical conclusion is that postconditions must be evaluated upon
>> exceptional return.
> 
> Consider a constructor. It's postcondition is the class invariant is
> satisfied. If it throws, the object is not successfully constructed and
> the invariant does not hold.

If the constructor fails, the object never existed.  Nothing to validate is valid.