Fixes #18438

Change-Id: I9599c1536d5e8bad7662b8ffa19e9b0746e27e60
Reviewed-on: https://go-review.googlesource.com/44000Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>