cmd/compile: add support for alternative comparable semantics
Add the experimental compiler flag -altcomparable. If set, the
compiler uses alternative comparable semantics: any ordinary
(non-type parameter) interface implements the comparable
constraint.
This permits experimenting with this alternative semantics
akin to what is proposed in #52509.
For #52509.
Change-Id: I64192eee6f2a550eeb50de011079f2f0b994cf94
Reviewed-on: https://go-review.googlesource.com/c/go/+/444636
Run-TryBot: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Robert Griesemer <gri@google.com> Reviewed-by: Robert Griesemer <gri@google.com> Reviewed-by: Robert Findley <rfindley@google.com>