I see. This isn't always true, many places in the standard library do not document what error they will return. Changing these wouldn't violate the Go1 guarante

I see. This isn't always true, many places in the standard library do not document what error they will return. Changing these wouldn't violate the Go1 guarantee either. I see that other people have made the argument in support of Dave Cheney's approach already so I won't repeat it.