You must have a Studio support contract to actually file a bug against Studio. But you can post comments, questions, and bug reports in this forum, or in the forum for Studio compilers.
We are always open to informal bug reports, and many bugs reported in the forum have been fixed due to the forum posting. We might also be able to suggest a workaround. Bug fixes appear in the next release, and bugs can also be fixed in patches to existing releases. You must have a service contract to request a patch.