[release-branch.go1.19] sync/atomic: allow linked list of atomic pointers again
For #56603, CL 448275 added a _ [0]T field to atomic.Pointer,
so that different kinds of atomic.Pointer are not convertible.
Unfortunately, that breaks code like:
type List struct {
Next atomic.Pointer[List]
}
which should be valid, just as using Next *List is valid.
Instead, we get:
./atomic_test.go:2533:6: invalid recursive type List
./atomic_test.go:2533:6: List refers to
./atomic_test.go:2534:13: "sync/atomic".Pointer refers to
./atomic_test.go:2533:6: List
Fix by using _[0]*T instead.
For #56638.
Fixes #57124.
Change-Id: Icc4c83c691d35961d20cb14b824223d6c779ac5e
Reviewed-on: https://go-review.googlesource.com/c/go/+/450655
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
(cherry picked from commit
b14cf3d93ae5c477dd35f13f6ba41044f01a7f7d)
Reviewed-on: https://go-review.googlesource.com/c/go/+/452438
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>