Fixes #27930

Change-Id: I31ad3fdb74d74152268c59ae4c651cc4c8c1716d
Reviewed-on: https://go-review.googlesource.com/c/142217Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>