mixintemplate WHOISFiberDelegate(alias onSuccess, alias onFailure = null, Flag!"alwaysLookup" alwaysLookup = No.alwaysLookup)
static if((paramNames.length == 0) || !is(typeof(mixin (paramNames[0])) : IRCPlugin))
=
"`WHOISFiberDelegate` should be mixed into the context of an event handler. " ~ "(First parameter of `%s` is not an `IRCPlugin` subclass)";