Tried that on Ubuntu 18.04.2. It pointed to disco, and the upgrade worked. Usually, we are supposed to first move to the nearest repo, and then to the next, and so on.
Well, for the few of us, who move their installs to the next development repos, this is not a problem, that is, there’s no need to name the repo as devel, but wait for the next repo name and update. Ubuntu becomes a rolling distro, with a slight wait.