go/types, types2: don't report assignment mismatch errors if there are other errors
Change the Checker.use/useLHS functions to report if all "used"
expressions evaluated without error. Use that information to
control whether to report an assignment mismatch error or not.
This will reduce the number of errors reported per assignment,
where the assignment mismatch is only one of the errors.
Change-Id: Ia0fc3203253b002e4e1d5759d8d5644999af6884
Reviewed-on: https://go-review.googlesource.com/c/go/+/478756 Reviewed-by: Robert Findley <rfindley@google.com> Reviewed-by: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>