I have to agree with Lindley on this one [yes, it does happen. ].

For the "standard" attributes which have a direct (or very close) mapping to the existing Visual C++ attributes, it would be a BIG help if the standard syntax was supported [this should primarilty impact the lexical analysis and not the internals of the compiler].

For those which do not match, having them parsed and either generating a "non-supported" error, or an "ignored" warning (ideally configurable between the two) would be a great help in keeping source code "clean".