fix #514

Also ensure that people can remove their own persistent modes via CS AMODE

irc/channel.go

@@ -395,7 +395,7 @@ func channelUserModeHasPrivsOver(clientMode modes.Mode, targetMode modes.Mode) b
 		return targetMode != modes.ChannelFounder && targetMode != modes.ChannelAdmin
 	case modes.Halfop:
 		// halfops cannot kick other halfops
-		return targetMode != modes.ChannelFounder && targetMode != modes.ChannelAdmin && targetMode != modes.Halfop
+		return targetMode == modes.Voice || targetMode == modes.Mode(0)
 	default:
 		// voice and unprivileged cannot kick anyone
 		return false

irc/modes.go

@@ -277,6 +277,9 @@ func (channel *Channel) ProcessAccountToUmodeChange(client *Client, change modes
 		hasPrivs = true
 	} else if channelUserModeHasPrivsOver(clientMode, targetModeNow) && channelUserModeHasPrivsOver(clientMode, targetModeAfter) {
 		hasPrivs = true
+	} else if change.Op == modes.Remove && account == change.Arg {
+		// you can always de-op yourself
+		hasPrivs = true
 	}
 	if !hasPrivs {
 		return nil, errInsufficientPrivs