[BUG] JSQLParser 5.3 : MySQL : Cannot parse DROP COLUMN where "type" is the column name

[minleejae]

Failing SQL Feature:

• Cannot parse ALTER TABLE ... DROP COLUMN command where type is the column name
• TYPE is a non-reserved keyword in MySQL 8.0 (see MySQL keyword list), so ALTER TABLE nullable_tbl DROP COLUMN type; is valid MySQL syntax without any quoting

SQL Example:

ALTER TABLE nullable_tbl DROP COLUMN type;

fails with:

net.sf.jsqlparser.parser.ParseException: Encountered unexpected token: "type" "TYPE"
    at line 1, column 38.

Was expecting one of:

    "IF"
    "NAME"
    <S_IDENTIFIER>
    <S_QUOTED_IDENTIFIER>

while the same identifier parses fine in other contexts:

SELECT type FROM nullable_tbl;                  -- OK
ALTER TABLE nullable_tbl DROP COLUMN `type`;    -- OK (quoted)

Software Information:

• JSQLParser 5.3 (also reproducible with current master: KeywordOrIdentifier() accepts K_NAME | K_NEXT | K_VALUE | K_PUBLIC | K_STRING | K_DATA but not K_TYPE)
• MySQL

Tips:

• Same class of bug as [BUG] JSQLParser 5.3 : PostgreSQL : Cannot parse DROP COLUMN command where data is the column name #2339 (column named data), which was fixed by [fix] Add 'K_DATA' to KeywordOrIdentifier to allow usages of 'data' as an identifier #2340 adding K_DATA to KeywordOrIdentifier(). Adding K_TYPE the same way fixes this case — I will raise a PR shortly.
• For reference, other MySQL non-reserved words that currently fail in the same DROP COLUMN position on master: comment, action, position, format, domain (and the datatype-token family text, date, year, timestamp, which probably needs a different approach).