Fixes #30199

Change-Id: Ib4586e3facb8c0985c8882482d94843b648b9d2f
Reviewed-on: https://go-review.googlesource.com/c/162257
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>