I want to think more carefully about this.

We put this in because Marshal encoded named []byte but Unmarshal rejected them.
And we noticed that Marshal's behavior was undocumented so we documented it.
But I am starting to think the docs and Unmarshal were correct and Marshal's
behavior was the problem.

Rolling back to give us more time to think.

««« original CL description
json: unmarshal types that are byte slices.

The json package cheerfully would marshal

        type S struct {
                IP net.IP
        }

but would give an error when unmarshalling.  This change allows any
type whose concrete type is a byte slice to be unmarshalled from a
string.

Fixes #5086.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/11161044

»»»

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/11042046