//go:xyz is dedicated syntax that is compatible with both the language spec and other toolchains that don't know about it.

It's an overloaded comment. I am personally quite fine with it, I don't think it's bad. but it is an overloaded comment.

I'm no longer sure what you're saying. You asked why they didn't go with dedicated syntax, I listed two advantageous aspects of the chosen syntax. We know it's an overloaded comment: that's literally one of the advantages.

Well, I've been unable to follow you as well, then. Obviously if they'd used a different type of syntax (e.g. using # for annotations), those would also be compatible with the language spec, and other implementations would still be just as capable of ignoring all unknown annotations.

(Though for the record, talking about alternative implementations when discussing Go is kind of a funny joke.)

Is gccgo a joke to you?

Maybe? It's stuck at 1.18 without generics and no one has replaced its maintainer, Ian Lance Taylor, who seems to have moved on after leaving Google.

But to be fair to alternative toolchains, TinyGo and TamaGo are also a thing.

Ian Lance Taylor is in the recent commit history for the main Go implementation. He's not working at Google any more but he's still active.

I meant gccgo specifically, I don't doubt he's still active with Go in general.

Good luck compiling on a toolchain that doesn't know about //go:embed or /* */import "C" comments.