If you try to add a member to a project he's already a member of (for example https://wikitech.wikimedia.org/w/index.php?title=Special:NovaProject&action=addmember&projectname=tools&member=Tim+Landscheidt), the error message is very general: "Failed to add Tim Landscheidt to tools."

It would be nice if this could be more verbose in this (common) case, because otherwise, to confirm that this is the true cause of the error, you have to go to the project's page and search through all the members to see if he's already there.

Version: unspecified
Severity: enhancement