did you run the tests after your fixes?
Because I tried to integrate another fixes related to date = string as proposed in Squeak by chris
but a lot of date related tests break. and we should be cautious.
I checked for senders of asUnixTime in the image and there weren't any. Just to be on the safe side I've run all the tests in KernelTests-Chronology; all green.
I've updated the issue (
#2644) to include a test and have attached a change set which includes the change to asUnixTime and an associated test.