D-Programming-Language/dmd — pull request #3287 by schuetzm (2014-02-19 12:01:14+00:00)
Title: Give users some guidance on how to handle missing default cases.

In light of this discussion [1], I think it would be a good idea to explicitly tell the user to put `assert(0)` in their default case, if they don't want to handle it.

Feel free to suggest a better phrasing or a nicer formatting.

[1] http://forum.dlang.org/thread/mailman.122.1392565409.6445.digitalmars-d@puremagic.com?page=6#post-ldvv6r:2431ha:241:40digitalmars.com