Correct. I don't understand why you are saying that, though. The argument I'm making is that x and y's *types* (not underlying) types are identical (actually, the argument I *was* making was different, but still had little to do with underlying types).
The spec <https://golang.org/ref/spec#Type_identity> says > A defined type is always different from any other type. Otherwise, two types are identical if their underlying type literals are structurally equivalent; that is, they have the same literal structure and corresponding components have identical types. In detail: Now, as neither x's nor y's types are defined, the first sentence doesn't apply. So we have to compare the structure of their underlying types. The relevant part of that list is > Two channel types are identical if they have identical element types and the same direction. So we have to check whether `error` and `interface{ Error() string }` are identical. And that's where the question of whether error is a defined type comes in (as I said, I'd argue that with the spec as-is it *probably* isn't. It's at least not clearly stated). If `error` is defined, then the two types are different; a defined type is different from any other type. If `error` is *not* defined, then we fall back to comparing the structure of their underlying types. The structural comparison says they *are* different. So, really, using channels was maybe a bit of a red-herring. As I said, the argument I was making still applies. But the argument that `error` and `interface{ Error() string }` *should* be identical if error is not defined is easier to make. On Fri, May 8, 2020 at 6:08 PM Jan Mercl <0xj...@gmail.com> wrote: > On Fri, May 8, 2020 at 5:57 PM Axel Wagner > <axel.wagner...@googlemail.com> wrote: > > > > I'm happy to report, that I *think* I found an inconsistency with error > not being a defined type: > > https://play.golang.org/p/gpy6S17wzIM > > I don't follow. Type of x is not a defined type and neither is type of > y. The underlying type of x is not the same as the underlying type of > y. > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAEkBMfH6L_Q5nj3A%2BNrp%2Bb7mBBK6BwdjLpX9KAzxPWaz-ac3kQ%40mail.gmail.com.
