Fixes #29437

Change-Id: Ice0a03a543e564d66651bfdfce5cd32ebaa35926
Reviewed-on: https://go-review.googlesource.com/c/155746
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>