cmd/compile/internal/noder: enable type aliases in type checker

This CL fixes an initialization loop during IR construction, that
stems from IR lacking first-class support for aliases. As a
workaround, we avoid publishing alias declarations until the RHS type
expression has been constructed.

Thanks to gri@ for investigating while I was out.

Fixes #66873.

Change-Id: I11e0d96ea6c357c295da47f44b6ec408edef89b7
Reviewed-on: https://go-review.googlesource.com/c/go/+/585399
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/test/fixedbugs/issue66873.go b/test/fixedbugs/issue66873.go
new file mode 100644
index 0000000000..2f49cc933d
--- /dev/null
+++ b/test/fixedbugs/issue66873.go
@@ -0,0 +1,15 @@
+// compile
+
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package p
+
+func f(A) {}
+
+type T int
+
+type A = T
+
+func (A) m() {}