all: delete aliastypeparams GOEXPERIMENT

Always enable aliastypeparams and remove the GOEXPERIMENT.

Change-Id: Ic38fe25b0bba312a7f83f7bb94b57ab75ce0f0c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/691956
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Mark Freeman <markfreeman@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

src/cmd/compile/internal/noder/unified.go

@@ -7,7 +7,6 @@ package noder
 import (
 	"cmp"
 	"fmt"
-	"internal/buildcfg"
 	"internal/pkgbits"
 	"internal/types/errors"
 	"io"
@@ -464,11 +463,8 @@ func readPackage(pr *pkgReader, importpkg *types.Pkg, localStub bool) {
 // writeUnifiedExport writes to `out` the finalized, self-contained
 // Unified IR export data file for the current compilation unit.
 func writeUnifiedExport(out io.Writer) {
-	// Use V2 as the encoded version aliastypeparams GOEXPERIMENT is enabled.
-	version := pkgbits.V1
-	if buildcfg.Experiment.AliasTypeParams {
-		version = pkgbits.V2
-	}
+	// Use V2 as the encoded version for aliastypeparams.
+	version := pkgbits.V2
 	l := linker{
 		pw: pkgbits.NewPkgEncoder(version, base.Debug.SyncFrames),
 

src/cmd/compile/internal/noder/writer.go

@@ -96,11 +96,8 @@ type pkgWriter struct {
 // newPkgWriter returns an initialized pkgWriter for the specified
 // package.
 func newPkgWriter(m posMap, pkg *types2.Package, info *types2.Info, otherInfo map[*syntax.FuncLit]bool) *pkgWriter {
-	// Use V2 as the encoded version aliastypeparams GOEXPERIMENT is enabled.
-	version := pkgbits.V1
-	if buildcfg.Experiment.AliasTypeParams {
-		version = pkgbits.V2
-	}
+	// Use V2 as the encoded version for aliastypeparams.
+	version := pkgbits.V2
 	return &pkgWriter{
 		PkgEncoder: pkgbits.NewPkgEncoder(version, base.Debug.SyncFrames),
 

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

@@ -8,7 +8,6 @@ import (
 	"cmd/compile/internal/syntax"
 	"fmt"
 	"go/constant"
-	"internal/buildcfg"
 	. "internal/types/errors"
 	"slices"
 )
@@ -525,10 +524,6 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *syntax.TypeDecl, def *TypeN
 
 			// handle type parameters even if not allowed (Alias type is supported)
 			if tparam0 != nil {
-				if !versionErr && !buildcfg.Experiment.AliasTypeParams {
-					check.error(tdecl, UnsupportedFeature, "generic type alias requires GOEXPERIMENT=aliastypeparams")
-					versionErr = true
-				}
 				check.openScope(tdecl, "type parameters")
 				defer check.closeScope()
 				check.collectTypeParams(&alias.tparams, tdecl.TParamList)

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

@@ -11,7 +11,6 @@ import (
 	"cmd/compile/internal/syntax"
 	"errors"
 	"fmt"
-	"internal/buildcfg"
 	. "internal/types/errors"
 )
 
@@ -130,10 +129,6 @@ func (check *Checker) instance(pos syntax.Pos, orig genericType, targs []Type, e
 		res = check.newNamedInstance(pos, orig, targs, expanding) // substituted lazily
 
 	case *Alias:
-		if !buildcfg.Experiment.AliasTypeParams {
-			assert(expanding == nil) // Alias instances cannot be reached from Named types
-		}
-
 		// verify type parameter count (see go.dev/issue/71198 for a test case)
 		tparams := orig.TypeParams()
 		if !check.validateTArgLen(pos, orig.obj.Name(), tparams.Len(), len(targs)) {

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

@@ -99,8 +99,7 @@ var testObjects = []struct {
 	{"type t = struct{f int}", "t", "type p.t = struct{f int}", false},
 	{"type t = func(int)", "t", "type p.t = func(int)", false},
 	{"type A = B; type B = int", "A", "type p.A = p.B", true},
-	{"type A[P ~int] = struct{}", "A", "type p.A[P ~int] = struct{}", true}, // requires GOEXPERIMENT=aliastypeparams
-
+	{"type A[P ~int] = struct{}", "A", "type p.A[P ~int] = struct{}", true},
 	{"var v int", "v", "var p.v int", false},
 
 	{"func f(int) string", "f", "func p.f(int) string", false},
@@ -114,10 +113,6 @@ func TestObjectString(t *testing.T) {
 
 	for i, test := range testObjects {
 		t.Run(fmt.Sprint(i), func(t *testing.T) {
-			if test.alias {
-				revert := setGOEXPERIMENT("aliastypeparams")
-				defer revert()
-			}
 			src := "package p; " + test.src
 			conf := Config{Error: func(error) {}, Importer: defaultImporter(), EnableAlias: test.alias}
 			pkg, err := typecheck(src, &conf, nil)

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

@@ -332,6 +332,8 @@ func TestStdFixed(t *testing.T) {
 		"issue49814.go",  // go/types does not have constraints on array size
 		"issue56103.go",  // anonymous interface cycles; will be a type checker error in 1.22
 		"issue52697.go",  // types2 does not have constraints on stack size
+		"issue68054.go",  // this test requires GODEBUG=gotypesalias=1
+		"issue68580.go",  // this test requires GODEBUG=gotypesalias=1
 		"issue73309.go",  // this test requires GODEBUG=gotypesalias=1
 		"issue73309b.go", // this test requires GODEBUG=gotypesalias=1
 

src/go/types/decl.go

@@ -9,7 +9,6 @@ import (
 	"go/ast"
 	"go/constant"
 	"go/token"
-	"internal/buildcfg"
 	. "internal/types/errors"
 	"slices"
 )
@@ -600,10 +599,6 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *ast.TypeSpec, def *TypeName
 
 			// handle type parameters even if not allowed (Alias type is supported)
 			if tparam0 != nil {
-				if !versionErr && !buildcfg.Experiment.AliasTypeParams {
-					check.error(tdecl, UnsupportedFeature, "generic type alias requires GOEXPERIMENT=aliastypeparams")
-					versionErr = true
-				}
 				check.openScope(tdecl, "type parameters")
 				defer check.closeScope()
 				check.collectTypeParams(&alias.tparams, tdecl.TypeParams)

src/go/types/instantiate.go

@@ -14,7 +14,6 @@ import (
 	"errors"
 	"fmt"
 	"go/token"
-	"internal/buildcfg"
 	. "internal/types/errors"
 )
 
@@ -133,10 +132,6 @@ func (check *Checker) instance(pos token.Pos, orig genericType, targs []Type, ex
 		res = check.newNamedInstance(pos, orig, targs, expanding) // substituted lazily
 
 	case *Alias:
-		if !buildcfg.Experiment.AliasTypeParams {
-			assert(expanding == nil) // Alias instances cannot be reached from Named types
-		}
-
 		// verify type parameter count (see go.dev/issue/71198 for a test case)
 		tparams := orig.TypeParams()
 		if !check.validateTArgLen(pos, orig.obj.Name(), tparams.Len(), len(targs)) {

src/go/types/object_test.go

@@ -99,8 +99,7 @@ var testObjects = []struct {
 	{"type t = struct{f int}", "t", "type p.t = struct{f int}", false},
 	{"type t = func(int)", "t", "type p.t = func(int)", false},
 	{"type A = B; type B = int", "A", "type p.A = p.B", true},
-	{"type A[P ~int] = struct{}", "A", "type p.A[P ~int] = struct{}", true}, // requires GOEXPERIMENT=aliastypeparams
-
+	{"type A[P ~int] = struct{}", "A", "type p.A[P ~int] = struct{}", true},
 	{"var v int", "v", "var p.v int", false},
 
 	{"func f(int) string", "f", "func p.f(int) string", false},
@@ -115,8 +114,6 @@ func TestObjectString(t *testing.T) {
 	for i, test := range testObjects {
 		t.Run(fmt.Sprint(i), func(t *testing.T) {
 			if test.alias {
-				revert := setGOEXPERIMENT("aliastypeparams")
-				defer revert()
 				t.Setenv("GODEBUG", "gotypesalias=1")
 			}
 

src/go/types/stdlib_test.go

@@ -334,6 +334,8 @@ func TestStdFixed(t *testing.T) {
 		"issue49814.go",  // go/types does not have constraints on array size
 		"issue56103.go",  // anonymous interface cycles; will be a type checker error in 1.22
 		"issue52697.go",  // go/types does not have constraints on stack size
+		"issue68054.go",  // this test requires GODEBUG=gotypesalias=1
+		"issue68580.go",  // this test requires GODEBUG=gotypesalias=1
 		"issue73309.go",  // this test requires GODEBUG=gotypesalias=1
 		"issue73309b.go", // this test requires GODEBUG=gotypesalias=1
 

src/internal/buildcfg/exp.go

@@ -79,10 +79,9 @@ func ParseGOEXPERIMENT(goos, goarch, goexp string) (*ExperimentFlags, error) {
 	dwarf5Supported := (goos != "darwin" && goos != "ios" && goos != "aix")
 
 	baseline := goexperiment.Flags{
-		RegabiWrappers:  regabiSupported,
-		RegabiArgs:      regabiSupported,
-		AliasTypeParams: true,
-		Dwarf5:          dwarf5Supported,
+		RegabiWrappers: regabiSupported,
+		RegabiArgs:     regabiSupported,
+		Dwarf5:         dwarf5Supported,
 	}
 
 	// Start with the statically enabled set of experiments.

src/internal/goexperiment/exp_aliastypeparams_off.go

@@ -1,8 +0,0 @@
-// Code generated by mkconsts.go. DO NOT EDIT.
-
-//go:build !goexperiment.aliastypeparams
-
-package goexperiment
-
-const AliasTypeParams = false
-const AliasTypeParamsInt = 0

src/internal/goexperiment/exp_aliastypeparams_on.go

@@ -1,8 +0,0 @@
-// Code generated by mkconsts.go. DO NOT EDIT.
-
-//go:build goexperiment.aliastypeparams
-
-package goexperiment
-
-const AliasTypeParams = true
-const AliasTypeParamsInt = 1

src/internal/goexperiment/flags.go

@@ -100,11 +100,6 @@ type Flags struct {
 	// inlining phase within the Go compiler.
 	NewInliner bool
 
-	// AliasTypeParams enables type parameters for alias types.
-	// Requires that gotypesalias=1 is set with GODEBUG.
-	// This flag will be removed with Go 1.25.
-	AliasTypeParams bool
-
 	// Synctest enables the testing/synctest package.
 	Synctest bool
 

src/internal/types/testdata/fixedbugs/issue67683.go

@@ -1,4 +1,4 @@
-// -goexperiment=aliastypeparams -gotypesalias=1
+// -gotypesalias=1
 
 // Copyright 2024 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style

src/internal/types/testdata/fixedbugs/issue69576.go

@@ -1,4 +1,4 @@
-// -goexperiment=aliastypeparams -gotypesalias=1
+// -gotypesalias=1
 
 // Copyright 2024 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style

src/internal/types/testdata/spec/typeAliases1.23b.go

@@ -1,4 +1,4 @@
-// -lang=go1.23 -gotypesalias=1 -goexperiment=aliastypeparams
+// -lang=go1.23 -gotypesalias=1
 
 // Copyright 2024 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style

test/fixedbugs/issue68054.go

@@ -1,4 +1,4 @@
-// compile -goexperiment aliastypeparams
+// compile
 
 // Copyright 2024 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style

test/fixedbugs/issue68526.dir/a/a.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build goexperiment.aliastypeparams
-
 package a
 
 type A[T any] = struct{ F T }

test/fixedbugs/issue68526.dir/main.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build goexperiment.aliastypeparams
-
 package main
 
 import (

test/fixedbugs/issue68526.go

@@ -1,4 +1,4 @@
-// runindir -goexperiment aliastypeparams -gomodversion "1.23"
+// runindir -gomodversion "1.23"
 
 // Copyright 2024 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style

test/fixedbugs/issue68580.go

@@ -1,4 +1,4 @@
-// compile -goexperiment aliastypeparams
+// compile
 
 // Copyright 2024 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style