internal/aliases: remove Alias and Unalias

These two declarations can now safely be accessed directly
from go/types.

Also, remove all mention of internal/aliases from gopls/...
We can enable two suppressed tests now that go1.23 is assured.

Updates golang/go#46477

Change-Id: I9ae8536b0d022e3300b285547c18202bed302cf2
Reviewed-on: https://go-review.googlesource.com/c/tools/+/614638
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Commit-Queue: Tim King <taking@google.com>
Reviewed-by: Tim King <taking@google.com>

cmd/godex/print.go

@@ -12,8 +12,6 @@ import (
 	"go/types"
 	"io"
 	"math/big"
-
-	"golang.org/x/tools/internal/aliases"
 )
 
 // TODO(gri) use tabwriter for alignment?
@@ -58,7 +56,7 @@ func (p *printer) printf(format string, args ...interface{}) {
 // denoted by obj is not an interface and has methods. Otherwise it returns
 // the zero value.
 func methodsFor(obj *types.TypeName) (*types.Named, []*types.Selection) {
-	named, _ := aliases.Unalias(obj.Type()).(*types.Named)
+	named, _ := types.Unalias(obj.Type()).(*types.Named)
 	if named == nil {
 		// A type name's type can also be the
 		// exported basic type unsafe.Pointer.

cmd/godex/writetype.go

@@ -14,8 +14,6 @@ package main
 
 import (
 	"go/types"
-
-	"golang.org/x/tools/internal/aliases"
 )
 
 func (p *printer) writeType(this *types.Package, typ types.Type) {
@@ -177,9 +175,9 @@ func (p *printer) writeTypeInternal(this *types.Package, typ types.Type, visited
 			p.print(")")
 		}
 
-	case *aliases.Alias:
+	case *types.Alias:
 		// TODO(adonovan): display something aliasy.
-		p.writeTypeInternal(this, aliases.Unalias(t), visited)
+		p.writeTypeInternal(this, types.Unalias(t), visited)
 
 	case *types.Named:
 		s := "<Named w/o object>"

go/analysis/passes/composite/composite.go

@@ -15,7 +15,6 @@ import (
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/typeparams"
 )
 
@@ -72,7 +71,7 @@ func run(pass *analysis.Pass) (interface{}, error) {
 			return
 		}
 		var structuralTypes []types.Type
-		switch typ := aliases.Unalias(typ).(type) {
+		switch typ := types.Unalias(typ).(type) {
 		case *types.TypeParam:
 			terms, err := typeparams.StructuralTerms(typ)
 			if err != nil {
@@ -146,7 +145,7 @@ func run(pass *analysis.Pass) (interface{}, error) {
 // isLocalType reports whether typ belongs to the same package as pass.
 // TODO(adonovan): local means "internal to a function"; rename to isSamePackageType.
 func isLocalType(pass *analysis.Pass, typ types.Type) bool {
-	switch x := aliases.Unalias(typ).(type) {
+	switch x := types.Unalias(typ).(type) {
 	case *types.Struct:
 		// struct literals are local types
 		return true

go/analysis/passes/copylock/copylock.go

@@ -17,7 +17,6 @@ import (
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/typeparams"
 	"golang.org/x/tools/internal/versions"
 )
@@ -286,7 +285,7 @@ func lockPath(tpkg *types.Package, typ types.Type, seen map[types.Type]bool) typ
 	}
 	seen[typ] = true
 
-	if tpar, ok := aliases.Unalias(typ).(*types.TypeParam); ok {
+	if tpar, ok := types.Unalias(typ).(*types.TypeParam); ok {
 		terms, err := typeparams.StructuralTerms(tpar)
 		if err != nil {
 			return nil // invalid type

go/analysis/passes/deepequalerrors/deepequalerrors.go

@@ -15,7 +15,6 @@ import (
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
-	"golang.org/x/tools/internal/aliases"
 )
 
 const Doc = `check for calls of reflect.DeepEqual on error values
@@ -102,7 +101,7 @@ func containsError(typ types.Type) bool {
 					return true
 				}
 			}
-		case *types.Named, *aliases.Alias:
+		case *types.Named, *types.Alias:
 			return check(t.Underlying())
 
 		// We list the remaining valid type kinds for completeness.

go/analysis/passes/httpresponse/httpresponse.go

@@ -14,7 +14,6 @@ import (
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/typesinternal"
 )
 
@@ -137,7 +136,7 @@ func isHTTPFuncOrMethodOnClient(info *types.Info, expr *ast.CallExpr) bool {
 	if analysisutil.IsNamedType(typ, "net/http", "Client") {
 		return true // method on http.Client.
 	}
-	ptr, ok := aliases.Unalias(typ).(*types.Pointer)
+	ptr, ok := types.Unalias(typ).(*types.Pointer)
 	return ok && analysisutil.IsNamedType(ptr.Elem(), "net/http", "Client") // method on *http.Client.
 }
 

go/analysis/passes/internal/analysisutil/util.go

@@ -15,7 +15,6 @@ import (
 	"os"
 
 	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/analysisinternal"
 )
 
@@ -121,7 +120,7 @@ func Imports(pkg *types.Package, path string) bool {
 // This function avoids allocating the concatenation of "pkg.Name",
 // which is important for the performance of syntax matching.
 func IsNamedType(t types.Type, pkgPath string, names ...string) bool {
-	n, ok := aliases.Unalias(t).(*types.Named)
+	n, ok := types.Unalias(t).(*types.Named)
 	if !ok {
 		return false
 	}

go/analysis/passes/nilness/nilness.go

@@ -14,7 +14,6 @@ import (
 	"golang.org/x/tools/go/analysis/passes/buildssa"
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ssa"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/typeparams"
 )
 
@@ -300,7 +299,7 @@ func nilnessOf(stack []fact, v ssa.Value) nilness {
 		}
 	case *ssa.MakeInterface:
 		// A MakeInterface is non-nil unless its operand is a type parameter.
-		tparam, ok := aliases.Unalias(v.X.Type()).(*types.TypeParam)
+		tparam, ok := types.Unalias(v.X.Type()).(*types.TypeParam)
 		if !ok {
 			return isnonnil
 		}

go/analysis/passes/printf/printf.go

@@ -24,7 +24,6 @@ import (
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/typeparams"
 )
 
@@ -161,7 +160,7 @@ func maybePrintfWrapper(info *types.Info, decl ast.Decl) *printfWrapper {
 
 	// Check final parameter is "args ...interface{}".
 	args := params.At(nparams - 1)
-	iface, ok := aliases.Unalias(args.Type().(*types.Slice).Elem()).(*types.Interface)
+	iface, ok := types.Unalias(args.Type().(*types.Slice).Elem()).(*types.Interface)
 	if !ok || !iface.Empty() {
 		return nil
 	}
@@ -1013,7 +1012,7 @@ func checkPrint(pass *analysis.Pass, call *ast.CallExpr, fn *types.Func) {
 
 		typ := params.At(firstArg).Type()
 		typ = typ.(*types.Slice).Elem()
-		it, ok := aliases.Unalias(typ).(*types.Interface)
+		it, ok := types.Unalias(typ).(*types.Interface)
 		if !ok || !it.Empty() {
 			// Skip variadic functions accepting non-interface{} args.
 			return

go/analysis/passes/printf/types.go

@@ -10,7 +10,6 @@ import (
 	"go/types"
 
 	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/typeparams"
 )
 
@@ -73,7 +72,7 @@ func (m *argMatcher) match(typ types.Type, topLevel bool) bool {
 		return true
 	}
 
-	if typ, _ := aliases.Unalias(typ).(*types.TypeParam); typ != nil {
+	if typ, _ := types.Unalias(typ).(*types.TypeParam); typ != nil {
 		// Avoid infinite recursion through type parameters.
 		if m.seen[typ] {
 			return true
@@ -276,7 +275,7 @@ func (m *argMatcher) match(typ types.Type, topLevel bool) bool {
 }
 
 func isConvertibleToString(typ types.Type) bool {
-	if bt, ok := aliases.Unalias(typ).(*types.Basic); ok && bt.Kind() == types.UntypedNil {
+	if bt, ok := types.Unalias(typ).(*types.Basic); ok && bt.Kind() == types.UntypedNil {
 		// We explicitly don't want untyped nil, which is
 		// convertible to both of the interfaces below, as it
 		// would just panic anyway.

go/analysis/passes/shift/shift.go

@@ -21,7 +21,6 @@ import (
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/typeparams"
 )
 
@@ -100,7 +99,7 @@ func checkLongShift(pass *analysis.Pass, node ast.Node, x, y ast.Expr) {
 		return
 	}
 	var structuralTypes []types.Type
-	switch t := aliases.Unalias(t).(type) {
+	switch t := types.Unalias(t).(type) {
 	case *types.TypeParam:
 		terms, err := typeparams.StructuralTerms(t)
 		if err != nil {

go/analysis/passes/stringintconv/string.go

@@ -15,7 +15,6 @@ import (
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/analysisinternal"
 	"golang.org/x/tools/internal/typeparams"
 )
@@ -248,7 +247,7 @@ func run(pass *analysis.Pass) (interface{}, error) {
 
 func structuralTypes(t types.Type) ([]types.Type, error) {
 	var structuralTypes []types.Type
-	if tp, ok := aliases.Unalias(t).(*types.TypeParam); ok {
+	if tp, ok := types.Unalias(t).(*types.TypeParam); ok {
 		terms, err := typeparams.StructuralTerms(tp)
 		if err != nil {
 			return nil, err

go/analysis/passes/testinggoroutine/testinggoroutine.go

@@ -16,7 +16,6 @@ import (
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
-	"golang.org/x/tools/internal/aliases"
 )
 
 //go:embed doc.go
@@ -270,7 +269,7 @@ func forbiddenMethod(info *types.Info, call *ast.CallExpr) (*types.Var, *types.S
 func formatMethod(sel *types.Selection, fn *types.Func) string {
 	var ptr string
 	rtype := sel.Recv()
-	if p, ok := aliases.Unalias(rtype).(*types.Pointer); ok {
+	if p, ok := types.Unalias(rtype).(*types.Pointer); ok {
 		ptr = "*"
 		rtype = p.Elem()
 	}

go/analysis/passes/unsafeptr/unsafeptr.go

@@ -16,7 +16,6 @@ import (
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/aliases"
 )
 
 //go:embed doc.go
@@ -88,7 +87,7 @@ func isSafeUintptr(info *types.Info, x ast.Expr) bool {
 		// by the time we get to the conversion at the end.
 		// For now approximate by saying that *Header is okay
 		// but Header is not.
-		pt, ok := aliases.Unalias(info.Types[x.X].Type).(*types.Pointer)
+		pt, ok := types.Unalias(info.Types[x.X].Type).(*types.Pointer)
 		if ok && isReflectHeader(pt.Elem()) {
 			return true
 		}

go/analysis/passes/unusedwrite/unusedwrite.go

@@ -12,7 +12,6 @@ import (
 	"golang.org/x/tools/go/analysis/passes/buildssa"
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ssa"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/typeparams"
 )
 
@@ -142,7 +141,7 @@ func hasStructOrArrayType(v ssa.Value) bool {
 			//   func (t T) f() { ...}
 			// the receiver object is of type *T:
 			//   t0 = local T (t)   *T
-			if tp, ok := aliases.Unalias(alloc.Type()).(*types.Pointer); ok {
+			if tp, ok := types.Unalias(alloc.Type()).(*types.Pointer); ok {
 				return isStructOrArray(tp.Elem())
 			}
 			return false

go/callgraph/rta/rta.go

@@ -45,7 +45,6 @@ import (
 	"golang.org/x/tools/go/callgraph"
 	"golang.org/x/tools/go/ssa"
 	"golang.org/x/tools/go/types/typeutil"
-	"golang.org/x/tools/internal/aliases"
 )
 
 // A Result holds the results of Rapid Type Analysis, which includes the
@@ -374,7 +373,7 @@ func (r *rta) interfaces(C types.Type) []*types.Interface {
 		// and update the 'implements' relation.
 		r.interfaceTypes.Iterate(func(I types.Type, v interface{}) {
 			iinfo := v.(*interfaceTypeInfo)
-			if I := aliases.Unalias(I).(*types.Interface); implements(cinfo, iinfo) {
+			if I := types.Unalias(I).(*types.Interface); implements(cinfo, iinfo) {
 				iinfo.implementations = append(iinfo.implementations, C)
 				cinfo.implements = append(cinfo.implements, I)
 			}
@@ -417,7 +416,7 @@ func (r *rta) implementations(I *types.Interface) []types.Type {
 // Adapted from needMethods in go/ssa/builder.go
 func (r *rta) addRuntimeType(T types.Type, skip bool) {
 	// Never record aliases.
-	T = aliases.Unalias(T)
+	T = types.Unalias(T)
 
 	if prev, ok := r.result.RuntimeTypes.At(T).(bool); ok {
 		if skip && !prev {
@@ -456,11 +455,11 @@ func (r *rta) addRuntimeType(T types.Type, skip bool) {
 	// Each package maintains its own set of types it has visited.
 
 	var n *types.Named
-	switch T := aliases.Unalias(T).(type) {
+	switch T := types.Unalias(T).(type) {
 	case *types.Named:
 		n = T
 	case *types.Pointer:
-		n, _ = aliases.Unalias(T.Elem()).(*types.Named)
+		n, _ = types.Unalias(T.Elem()).(*types.Named)
 	}
 	if n != nil {
 		owner := n.Obj().Pkg()
@@ -479,7 +478,7 @@ func (r *rta) addRuntimeType(T types.Type, skip bool) {
 	}
 
 	switch t := T.(type) {
-	case *aliases.Alias:
+	case *types.Alias:
 		panic("unreachable")
 
 	case *types.Basic:

go/callgraph/rta/rta_test.go

@@ -22,7 +22,6 @@ import (
 	"golang.org/x/tools/go/packages"
 	"golang.org/x/tools/go/ssa"
 	"golang.org/x/tools/go/ssa/ssautil"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/testenv"
 	"golang.org/x/tools/internal/testfiles"
 	"golang.org/x/tools/txtar"
@@ -257,7 +256,7 @@ func check(t *testing.T, f *ast.File, pkg *ssa.Package, res *rta.Result) {
 		got := make(stringset)
 		res.RuntimeTypes.Iterate(func(key types.Type, value interface{}) {
 			if !value.(bool) { // accessible to reflection
-				typ := types.TypeString(aliases.Unalias(key), types.RelativeTo(pkg.Pkg))
+				typ := types.TypeString(types.Unalias(key), types.RelativeTo(pkg.Pkg))
 				got[typ] = true
 			}
 		})

go/callgraph/vta/graph.go

@@ -11,7 +11,6 @@ import (
 
 	"golang.org/x/tools/go/ssa"
 	"golang.org/x/tools/go/types/typeutil"
-	"golang.org/x/tools/internal/aliases"
 	"golang.org/x/tools/internal/typeparams"
 )
 
@@ -676,7 +675,7 @@ func (b *builder) multiconvert(c *ssa.MultiConvert) {
 		// This is a adaptation of x/exp/typeparams.NormalTerms which x/tools cannot depend on.
 		var terms []*types.Term
 		var err error
-		switch typ := aliases.Unalias(typ).(type) {
+		switch typ := types.Unalias(typ).(type) {
 		case *types.TypeParam:
 			terms, err = typeparams.StructuralTerms(typ)
 		case *types.Union:
@@ -745,7 +744,7 @@ func (b *builder) addInFlowEdge(s, d node) {
 
 // Creates const, pointer, global, func, and local nodes based on register instructions.
 func (b *builder) nodeFromVal(val ssa.Value) node {
-	if p, ok := aliases.Unalias(val.Type()).(*types.Pointer); ok && !types.IsInterface(p.Elem()) && !isFunction(p.Elem()) {
+	if p, ok := types.Unalias(val.Type()).(*types.Pointer); ok && !types.IsInterface(p.Elem()) && !isFunction(p.Elem()) {
 		// Nested pointer to interfaces are modeled as a special
 		// nestedPtrInterface node.
 		if i := interfaceUnderPtr(p.Elem()); i != nil {

go/callgraph/vta/graph_test.go

@@ -15,7 +15,6 @@ import (
 	"golang.org/x/tools/go/callgraph/cha"
 	"golang.org/x/tools/go/ssa"
 	"golang.org/x/tools/go/ssa/ssautil"
-	"golang.org/x/tools/internal/aliases"
 )
 
 func TestNodeInterface(t *testing.T) {
@@ -38,7 +37,7 @@ func TestNodeInterface(t *testing.T) {
 	reg := firstRegInstr(main) // t0 := *gl
 	X := pkg.Type("X").Type()
 	gl := pkg.Var("gl")
-	glPtrType, ok := aliases.Unalias(gl.Type()).(*types.Pointer)
+	glPtrType, ok := types.Unalias(gl.Type()).(*types.Pointer)
 	if !ok {
 		t.Fatalf("could not cast gl variable to pointer type")
 	}