go/types, types2: implement Alias proposal (export API)

This CL exports the previously unexported Alias type and
corresponding functions and methods per issue #63223.

Whether Alias types are used or not is controlled by
the gotypesalias setting with the GODEBUG environment
variable. Setting gotypesalias to "1" enables the Alias
types:

	GODEBUG=gotypesalias=1

By default, gotypesalias is not set.

Adjust test cases that enable/disable the use of Alias
types to use -gotypesalias=1 or -gotypesalias=0 rather
than -alias and -alias=false for consistency and to
avoid confusion.

For #63223.

Change-Id: I51308cad3320981afac97dd8c6f6a416fdb0be55
Reviewed-on: https://go-review.googlesource.com/c/go/+/541737
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@google.com>
This commit is contained in:
Robert Griesemer 2023-11-10 18:11:15 -08:00 committed by Gopher Robot
parent 42bd21be1c
commit 30de0b5ef4
46 changed files with 209 additions and 159 deletions

View file

@ -29,6 +29,7 @@ var All = []Info{
{Name: "gocachehash", Package: "cmd/go"},
{Name: "gocachetest", Package: "cmd/go"},
{Name: "gocacheverify", Package: "cmd/go"},
{Name: "gotypesalias", Package: "go/types"},
{Name: "http2client", Package: "net/http"},
{Name: "http2debug", Package: "net/http", Opaque: true},
{Name: "http2server", Package: "net/http"},