To your second point: Ian Lance Taylor explicitly says that Go has undefined behavior, which as you say is not just "don't know what it is". He (as he shows in

To your second point: Ian Lance Taylor explicitly says that Go has undefined behavior, which as you say is not just "don't know what it is". He (as he shows in this thread too) is, like me, very much aware of what UB is. He's even correcting people who are using the term "undefined" incorrectly. As for "memory safety", maybe you're right on the terminology. But this does mean that in Go a data race, being UB, can do anything. There are no guarantees of no use after free, or read/write out of bounds, anymore. If you create a data race in Go, you are in UB land. And that's one of the many many missed opportunities of Go.