Replacing use common::sense; with use strict; use warnings;

I've thought about that. Personally, I don't use common::sense, because I happen to disagree with its warnings policy. However, during the development of this module I've tried to get away with as few changes to JSON::XS as possible, so I haven't touched this part yet. But perhaps you're right, it's not really needed, and dropping the non-core dependency would be an advantage. In fact, given that the actual Perl code in the module consists of exactly 10 assignments and a few uses, perhaps even the strict and warnings could be omitted.

There are still some test issues.

Yes, I saw those among the test reports. The problem is that simdjson returns floating point numbers as doubles, which is fine if Perl's NV happens to be a double, but not when -Duselongdouble or -Dusequadmath is in effect. It appears to me, based on the test results, that the -Duselongdouble case is mostly fine, because the failing tests merely betray a slight loss of precision. The intermittent garbage in the -Dusequadmath case is more worrying. I do recall a(n unanswered) bug report to JSON::XS with the exact same symptoms, so there might be deeper problems with this mode.

In any case more care is warranted with number parsing, I'll try to do something about these failures.

Thanks for the reports!