RESERV. RESERV is meant for tokens like "now" and having them in that
category throws errors like these when used as an input date:

stark=# SELECT 'doy'::timestamptz;
ERROR:  unexpected dtype 33 while parsing timestamptz "doy"
LINE 1: SELECT 'doy'::timestamptz;
               ^
stark=# SELECT 'dow'::timestamptz;
ERROR:  unexpected dtype 32 while parsing timestamptz "dow"
LINE 1: SELECT 'dow'::timestamptz;
               ^

Found by LLVM's Libfuzzer