Fixes #15923

Change-Id: I3e56564365086ceb0bfc15db61db6fb446ab7448
Reviewed-on: https://go-review.googlesource.com/23760Reviewed-by: Sebastien Binet <seb.binet@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>