Much of the code for parsing parameter names looks like this:

                } else if (  "slop".equals(currentFieldName) 
                             || "phrase_slop".equals(currentFieldName) 
                             || "phraseSlop".equals(currentFieldName)) {

The parseField method already handles the parsing of alternatives (including camelCase and deprecated syntax). It also provides a central point for warning when deprecated parameter names are used (see #11033).

All existing code should be migrated to use parseField.