Working as intended. As the docs say,

No checking is done that the day of the month is within the month's valid
dates; any one- or two-digit value is accepted. For example February 31 and
even February 99 are valid dates, specifying dates in March and May. This
behavior is consistent with time.Date.

Thanks for very swift reply, appreciated.

Mentioned "31" and "99" for February does return "day out of range" error (as expected) . "00" instead overflows in the previous month with 'nil' error (unexpected)

(https://play.golang.org/p/o9lQ_TBTZH)

parse(...) DOES evaluate the validity of the day of the month.
...
// Validate the day of the month.
if day > daysIn(Month(month), year) {
return Time{}, &ParseError{alayout, avalue, "", value, ": day out of range"}
}

time.Parse("02.01.2006", "29.02.1970") -> returns "day out of range" error
time.Parse("02.01.2006", "00.01.1970") -> "1969-12-31 00:00:00 +0000 UTC"

This "00" overflowing from "00.01.1970" into "31.12.1969" with 'nil' error appears - to me - inconsistent.

Can I work on it?

@lucasalcantara Feel free to send a CL

@lucasalcantara, status?

Alternatively, anybody else (including @robpike) is welcome to send a CL.

@bradfitz sorry brad, my pc broke and will take a while to fix. So anyone can get this. I forgot to comment in here.

I can take this on, I've got the bandwidth and I've just prepared a CL for it, about to mail it.

Oops, the Gobot hadn't tagged this issue so I mailed a dupe CL https://go-review.googlesource.com/c/33434, @bradfitz's is ready to go, so I'll abandon mine :)