go/types: avoid race condition with dot-imported objects
It would be nice to have a test, but it requires running
this under the race detector which is a bit complicated
to set up; yet the fix is trivial. Verified manually that
it doesn't trip the race detector.
Fixes #32154.
Change-Id: I20bd746a07945c802f0476a1d8b1dfd83c87dae8
Reviewed-on: https://go-review.googlesource.com/c/go/+/183849
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>