go/types: rename isX predicates to allX, add simple is_X (step 1 of 2)
This is a port of CL 360955 to go/types. Note that go/types and types2
differ in handling of untyped nil within both Checker.shift and
Checker.implicitTypeAndValue.
A missing comment was added to Checker.indexExpr.
Change-Id: Ia9149ff9c0af68213c579090902ab7989828ddd2
Reviewed-on: https://go-review.googlesource.com/c/go/+/362534
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Robert Griesemer <gri@golang.org>