This worked in 7.3:
regression=# select '1999-jan-08'::date;
ERROR: date/time field value out of range: "1999-jan-08"
HINT: Perhaps you need a different "datestyle" setting.
Setting DateStyle to YMD doesn't help, and in any case I'd think that
this ought to be considered an unambiguous input format.
The variants
select 'jan-08-1999'::date;
select '08-jan-1999'::date;
both still work, so I think this is probably some small oversight in the
logic, but I haven't dug into it to find where.
Not sure if this qualifies as a must-fix-for-7.4 or not, but my vote
would be "yes" ...
regards, tom lane