types2: flip the default value of GODEBUG=gotypesalias=1
This CL changes the interpretation of the unset value
of gotypesalias to not equal "0".
This is a port of CL 577715 from go/types to types2,
with adjustments to go/types to keep the source code
in sync. Specifically:
- Re-introduce testing of both modes (gotypesalias=0,
gotypesalias=1) in go/types.
- Re-introduce setting of gotypesalias in some of the
tests for explicit documentation in go/types.
The compiler still uses the (now) non-default setting
due to a panic with the default setting that needs to
be debugged.
Also, the type checkers still don't call IncNonDefault
when the non-default setting of gotypesalias is used.
Change-Id: I1feed3eb334c202950ac5aadf49a74adcce0d8c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/579076
TryBot-Bypass: Robert Griesemer <gri@google.com> Reviewed-by: Robert Griesemer <gri@google.com> Reviewed-by: Alan Donovan <adonovan@google.com> Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>