[Issue 21169] make checkedint as a drop-in replacement of native int/long

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21169

--- Comment #3 from hsteoh at quickfur.ath.cx ---
Fix for issue (1): https://github.com/dlang/phobos/pull/7599

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