Question on cast string to date

[正华吕]

Hi,

    I test the following SQL in pg15dev (seems same behavior as the
previous version).

    select '2020701'::date;
    date
   ------------
    0202-07-01
   (1 row)

   At the first glance, the result seems quite strange.

   Go through the code, postgres use date_in to do the cast, and firstly
use last 2 chars to
   get the day, and the 2 chars to get the month, and all remaining chars
as year.

   The question here is: should we throw error for such input? Or what
standard postgres is
   using to cast such kind of string?

Thanks.