[IronPython] Exception for setting attributes of built-in type

[Dino Viehland]

Seo wrote:
> Exception for setting attributes of built-in type differs between
> CPython and IronPython. This is not purely theoretical, as
> zope.interface tries to set Implements declaration as __implemented__
> attribute of built-in type object, and excepts TypeError.
>
> Python 2.6.1
> >>> object.flag = True
> TypeError: can't set attributes of built-in/extension type 'object'
>
> IronPython 2.6
> >>> object.flag = True
> AttributeError: 'object' object has no attribute 'flag'
>
> I was surprised that CPython raises TypeError. Library Reference seems
> to mention it here:
>
> exception AttributeError
> Raised when an attribute reference or assignment fails. (When an
> object does not support attribute references or attribute assignments
> at all, TypeError is raised.)
> http://docs.python.org/library/exceptions.html
>
> What does it mean that "an object does not support attribute
> references or attribute assignments at all"?

Even though Guido said we didn't have to match it I've updated IronPython
so that we'll throw the same exception now.  The change will be in
tomorrow's source push to CodePlex.  We've matched specific exceptions
in the past and this one is at least documented :)