presto-hive/src/main/java/io/prestosql/plugin/hive/security/SqlStandardAccessControlMetadata.java/SqlStandardAccessControlMetadata/dropRole
class SqlStandardAccessControlMetadata:    @Override
    public void dropRole(ConnectorSession session, String role)
    {
        checkRoleIsNotReserved(role);
        metastore.dropRole(role);
    }