为什么GoDoc不显示接口变量？ [关闭]

Considering the following snippet:

package example

type Foo interface {
}

var Alpha = "alpha"
var Beta string = "beta"
var Gamma Foo = "gamma"

Both godoc (-http=:6060) and go doc ignore Gamma entirely, whilst Alpha and Beta are - of course - shown in the output. This behavior seems to be reproducible with any exported variable that is declared to be an interface type.

Why?

Unconfirmed at my system. I see all, including Gamma.

Var Gamma is placed after type Foo definition.

But at my system a devel version of golang is installed:

go version devel +1140207a3395 Wed Nov 20 13:47:37 2013 -0800 linux/amd64