Fixes #30959

Change-Id: I9d30d79e2dbb3f8c8d6555f8c64862b133638d5d
Reviewed-on: https://go-review.googlesource.com/c/go/+/169357Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rob Pike <r@golang.org>