Fixes #16120

Change-Id: Ia352558231e00baab5c698e93d7267564c07ec0c
Reviewed-on: https://go-review.googlesource.com/24242Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>