D-Programming-Language/dmd — pull request #1673 by AndrejMitrovic (2013-02-17 21:47:49+00:00)
Title:  Issue 6552 - Invalid warning on non-existent switch case fallthrough.

http://d.puremagic.com/issues/show_bug.cgi?id=6552

This also turns the fallthrough error into a warning since the error was only emitted when warnings are on (`-w`).

We could let it be an error, but in that case the check for `-w` has to go away.