Fixes #8833

Change-Id: I4523a1de112ed02371504e27882659bce8028a45
Reviewed-on: https://go-review.googlesource.com/24745Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>