Thanks! I added a reference to that in the blog post.

Interestingly, in 2012 Rob Pike explicitly said that Go is "not purely memory safe" because "sharing is legal": https://go.dev/talks/2012/splash.slide#49. However it is not entirely clear what he means by that (I was not able to find a recording of the talk), but it seems likely he's referring to this very issue.

> "The program should not be able to derive a bad address and just use it"

My example does exactly that, so -- as you say, Go mostly achieves this, but not entirely.

> Note that stated goal from 2009 is "good support for concurrency", not "concurrent-safe".

My argument is that being concurrency-unsafe implies being memory-unsafe, for the reasons laid down in the blog post. I understand that that is a somewhat controversial opinion. :)