Perl 6 will natively think of dates as number of floating point TAI
seconds from the year 2000. You can build any kind of date interface
on top of that, but we're going for simplicity and predictability.
If UTC goes ahead with with additional leap seconds, we will NOT use
Posix stretchy seconds to represent them. I'm personally rooting
for everyone to abandon leap seconds for civil time. Civil leap
adjustments really ought to be scheduled more than six months in
advance. Once a century would be about right.
But POSIX stretchy seconds must die.