go/types: generate initorder.go from types2 source

This CL reduces the amount of code that needs to be maintained
manually by about 320 LOC.

Change-Id: Ib797e86dd4abd3a9fe614787103f0e5cebd5e4ae
Reviewed-on: https://go-review.googlesource.com/c/go/+/565838
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Robert Griesemer <gri@google.com>

src/cmd/compile/internal/types2/initorder.go

@@ -314,11 +314,11 @@ func (a nodeQueue) Less(i, j int) bool {
 	return x.ndeps < y.ndeps || x.ndeps == y.ndeps && x.obj.order() < y.obj.order()
 }
 
-func (a *nodeQueue) Push(x interface{}) {
+func (a *nodeQueue) Push(x any) {
 	panic("unreachable")
 }
 
-func (a *nodeQueue) Pop() interface{} {
+func (a *nodeQueue) Pop() any {
 	n := len(*a)
 	x := (*a)[n-1]
 	x.index = -1 // for safety

src/go/types/generate_test.go

@@ -127,6 +127,7 @@ var filemap = map[string]action{
 	"gcsizes.go":      func(f *ast.File) { renameIdents(f, "IsSyncAtomicAlign64->_IsSyncAtomicAlign64") },
 	"hilbert_test.go": func(f *ast.File) { renameImportPath(f, `"cmd/compile/internal/types2"->"go/types"`) },
 	"infer.go":        func(f *ast.File) { fixTokenPos(f); fixInferSig(f) },
+	"initorder.go":    nil,
 	// "initorder.go": fixErrErrorfCall, // disabled for now due to unresolved error_ use implications for gopls
 	"instantiate.go":      func(f *ast.File) { fixTokenPos(f); fixCheckErrorfCall(f) },
 	"instantiate_test.go": func(f *ast.File) { renameImportPath(f, `"cmd/compile/internal/types2"->"go/types"`) },

src/go/types/initorder.go

@@ -1,3 +1,5 @@
+// Code generated by "go test -run=Generate -write=all"; DO NOT EDIT.
+
 // Copyright 2014 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.