Does this sound familar? You make a change to a library to optimize its performance or clean up technical debt or fix a bug, only to get a bug report: some very large, incomprehensibly opaque test is now failing. Or you add a new compiler optimization with a similar result. Now you have a major debugging job in an unfamiliar code base

Exactly a year ago (yesterday), Russ Cox submitted a proposal to add two new range capabilities to Go: range-over-int, and range-over-func. The former was added to Go 1.22. And the latter left me immediately skeptical. I spent a fair amount of time (as measured in Internet minutes) trying to understand the proposal, and eventually coming to the conslusion that I wasn’t very smart

Go 1.23 is coming soon, so it's a good time to explore what's new. The official release notes are pretty dry, so I prepared an interactive version with lots of examples showing what has changed and what the new behavior is