A program that called a subroutine which did nothing except return. Perhaps in the mists of time past the sub did in fact serve a purpose but there was no code there and no comments.

Still, I am more in favor of simply rendering unused code inert via "if 0=1 then" and leave a comment regarding why it is no longer being used. I do this because I've seen too many cases of code yanked that had to then be replaced. Worse (?) is code that is commented out by commenting out each line rather that testing a "never will be true" condition.

Of course, this all is assuming disk space is not a problem and that noone will ever care you are testing a condition which will never be true.