Package: emacs
Severity: minor
Tags: patch
X-Debbugs-Cc: rudalics@gmx.at

In some circumstances, next-buffer and previous-buffer do not have any
buffer to switch to, and in that case they silently do nothing.  (Strictly
speaking, they call switch-to-(next|prev)-buffer, which do nothing and
return nil).

I think they should throw a user-error, to inform the user about the
situation.