The book says "Comments begin with //." and "// +build" is a special comment. It was only replaced with "//go:build" 1.17 (2021) . So your statement incorrectly implied that this strict syntax distinction between directives and comments has always existed, what happened was people started doing this slowly over time and eventually noticed the disconnect and changed "// +build" which they could because all that stuff was implementation-defined behavior. Right now gofmt handles "// +build" "//+build" and "//go:build" by moving them to the top, adding //go:build if it doesn't exist and adding a space to "//+build", which already breaks setups that add a build comment.

Why would millions of programs becoming out of date with the spec make me happy. There is value in the language maintainers and go programmers talking about the same object. I don't disagree that '// ' is standard Go style (and more readable), but it would break all the code that uses //comments /// ////.

I DO agree that it wouldn't change much if by 'it' you mean the go language and it's tooling, a proper spec does prevent arbitrary change. But it should have been added at least 5 years ago.