Convert editable calendar parts to a worldTime value, or null when the
parts do not resolve to a real date on calendar.
Validity is checked by round-trip: the computed time is decomposed again and
must yield the same month, day-of-month, era year, and before-era flag. This
catches an out-of-range day (which would spill into the next month or into
intercalary days) and any era mismatch, without assuming uniform months.
Convert editable calendar parts to a worldTime value, or
nullwhen the parts do not resolve to a real date oncalendar.Validity is checked by round-trip: the computed time is decomposed again and must yield the same month, day-of-month, era year, and before-era flag. This catches an out-of-range day (which would spill into the next month or into intercalary days) and any era mismatch, without assuming uniform months.