Fixes #29983

Change-Id: I24077bde991e621c23d00973b2a77bb3a18e4ae7
Reviewed-on: https://go-review.googlesource.com/c/160180
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>