Old code appended, did not play well with a closure
with a ... param.

Fixes #11075.

Change-Id: Ib7c8590c5c4e576e798837e7499e00f3494efb4a
Reviewed-on: https://go-review.googlesource.com/12580Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: David Chase <drchase@google.com>