$u = User::newFromName( $this->mUsername );

		// Give extensions a way to indicate the username has been updated,
		// rather than telling the user the account doesn't exist.
		if ( !Hooks::run( 'LoginUserMigrated', array( $u, &$msg ) ) ) {
			$this->mAbortLoginErrorMsg = $msg;
			return self::USER_MIGRATED;
		}

		if ( !( $u instanceof User ) || !User::isUsableName( $u->getName() ) ) {
			return self::ILLEGAL;
		}