While John's suggestion will help, I've got a specific code change pattern of structured comments that I have applied retroactively to any of our changes outside a dedicated VoltDB module or a large end-of-the-class VoltDB appendage). It'll save me some hassle later if you could use it. It begins with a structured comment ending in a brief description of the intent of the change and uses structured commenting to disable "replaced" lines. Here's how it might look for this case:

                    // A VoltDB extension to allow toSQL on expressions in DDL
                    if (rangeVariable == null || rangeVariable.tableAlias == null) {
                    /* disable 1 line ...
-                    if (rangeVariable.tableAlias == null) {
                    ... disabled 1 line */
                    // End of VoltDB extension