Non-cooperatively terminating a shared-memory thread is an inherently unsafe thing to do, and basically every runtime that has an API for it regards it as a design mistake. See, e.g., https://docs.oracle.com/javase/8/docs/technotes/guides/concu... and https://learn.microsoft.com/en-us/windows/win32/api/processt.... (POSIX's pthread_cancel is somewhat different, and avoids some of the worst failure modes, but at the cost of not actually consistently killing the thread when you call it—and it still has a lot of problems besides that.) So I don't think Go is ever going to add this, nor should it.

(Having the go statement return a handle that you can block on would of course be completely fine, but at this point they're probably not going to do that either.)