Fixes #15654

Change-Id: I9bdaa9b76d480d75f24d95f0235efd4a79e3593e
Reviewed-on: https://go-review.googlesource.com/23320Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>