diff --git a/compiler/internal/aliases/aliases.go b/compiler/internal/aliases/aliases.go
deleted file mode 100644
index c24c2eee..00000000
--- a/compiler/internal/aliases/aliases.go
+++ /dev/null
@@ -1,32 +0,0 @@
-// 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 aliases
-
-import (
-	"go/token"
-	"go/types"
-)
-
-// Package aliases defines backward compatible shims
-// for the types.Alias type representation added in 1.22.
-// This defines placeholders for x/tools until 1.26.
-
-// NewAlias creates a new TypeName in Package pkg that
-// is an alias for the type rhs.
-//
-// The enabled parameter determines whether the resulting [TypeName]'s
-// type is an [types.Alias]. Its value must be the result of a call to
-// [Enabled], which computes the effective value of
-// GODEBUG=gotypesalias=... by invoking the type checker. The Enabled
-// function is expensive and should be called once per task (e.g.
-// package import), not once per call to NewAlias.
-func NewAlias(enabled bool, pos token.Pos, pkg *types.Package, name string, rhs types.Type) *types.TypeName {
-	if enabled {
-		tname := types.NewTypeName(pos, pkg, name, nil)
-		newAlias(tname, rhs)
-		return tname
-	}
-	return types.NewTypeName(pos, pkg, name, rhs)
-}
diff --git a/compiler/internal/aliases/aliases_go121.go b/compiler/internal/aliases/aliases_go121.go
deleted file mode 100644
index c027b9f3..00000000
--- a/compiler/internal/aliases/aliases_go121.go
+++ /dev/null
@@ -1,31 +0,0 @@
-// 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.
-
-//go:build !go1.22
-// +build !go1.22
-
-package aliases
-
-import (
-	"go/types"
-)
-
-// Alias is a placeholder for a go/types.Alias for <=1.21.
-// It will never be created by go/types.
-type Alias struct{}
-
-func (*Alias) String() string         { panic("unreachable") }
-func (*Alias) Underlying() types.Type { panic("unreachable") }
-func (*Alias) Obj() *types.TypeName   { panic("unreachable") }
-func Rhs(alias *Alias) types.Type     { panic("unreachable") }
-
-// Unalias returns the type t for go <=1.21.
-func Unalias(t types.Type) types.Type { return t }
-
-func newAlias(name *types.TypeName, rhs types.Type) *Alias { panic("unreachable") }
-
-// Enabled reports whether [NewAlias] should create [types.Alias] types.
-//
-// Before go1.22, this function always returns false.
-func Enabled() bool { return false }
diff --git a/compiler/internal/aliases/aliases_go122.go b/compiler/internal/aliases/aliases_go122.go
deleted file mode 100644
index b3299548..00000000
--- a/compiler/internal/aliases/aliases_go122.go
+++ /dev/null
@@ -1,63 +0,0 @@
-// 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.
-
-//go:build go1.22
-// +build go1.22
-
-package aliases
-
-import (
-	"go/ast"
-	"go/parser"
-	"go/token"
-	"go/types"
-)
-
-// Alias is an alias of types.Alias.
-type Alias = types.Alias
-
-// Rhs returns the type on the right-hand side of the alias declaration.
-func Rhs(alias *Alias) types.Type {
-	if alias, ok := any(alias).(interface{ Rhs() types.Type }); ok {
-		return alias.Rhs() // go1.23+
-	}
-
-	// go1.22's Alias didn't have the Rhs method,
-	// so Unalias is the best we can do.
-	return Unalias(alias)
-}
-
-// Unalias is a wrapper of types.Unalias.
-func Unalias(t types.Type) types.Type { return types.Unalias(t) }
-
-// newAlias is an internal alias around types.NewAlias.
-// Direct usage is discouraged as the moment.
-// Try to use NewAlias instead.
-func newAlias(tname *types.TypeName, rhs types.Type) *Alias {
-	a := types.NewAlias(tname, rhs)
-	// TODO(go.dev/issue/65455): Remove kludgy workaround to set a.actual as a side-effect.
-	Unalias(a)
-	return a
-}
-
-// Enabled reports whether [NewAlias] should create [types.Alias] types.
-//
-// This function is expensive! Call it sparingly.
-func Enabled() bool {
-	// The only reliable way to compute the answer is to invoke go/types.
-	// We don't parse the GODEBUG environment variable, because
-	// (a) it's tricky to do so in a manner that is consistent
-	//     with the godebug package; in particular, a simple
-	//     substring check is not good enough. The value is a
-	//     rightmost-wins list of options. But more importantly:
-	// (b) it is impossible to detect changes to the effective
-	//     setting caused by os.Setenv("GODEBUG"), as happens in
-	//     many tests. Therefore any attempt to cache the result
-	//     is just incorrect.
-	fset := token.NewFileSet()
-	f, _ := parser.ParseFile(fset, "a.go", "package p; type A = int", 0)
-	pkg, _ := new(types.Config).Check("p", fset, []*ast.File{f}, nil)
-	_, enabled := pkg.Scope().Lookup("A").Type().(*types.Alias)
-	return enabled
-}
diff --git a/compiler/internal/mod/mod.go b/compiler/internal/mod/mod.go
deleted file mode 100644
index ccb51114..00000000
--- a/compiler/internal/mod/mod.go
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
- * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package mod
-
-import (
-	"path"
-	"path/filepath"
-
-	"github.com/goplus/mod"
-	"github.com/goplus/mod/gopmod"
-)
-
-// Module represents a Go module.
-type Module = gopmod.Module
-
-// Load loads a Go module from a directory.
-func Load(dir string) (ret *Module, pkgPath string, err error) {
-	if dir, err = filepath.Abs(dir); err != nil {
-		return
-	}
-	_, gomod, err := mod.FindGoMod(dir)
-	if err != nil {
-		return
-	}
-	if ret, err = gopmod.LoadFrom(gomod, ""); err != nil {
-		return
-	}
-	relPath, err := filepath.Rel(ret.Root(), dir)
-	if err != nil {
-		return
-	}
-	pkgPath = path.Join(ret.Path(), filepath.ToSlash(relPath))
-	return
-}
diff --git a/compiler/internal/projs/proj.go b/compiler/internal/projs/proj.go
deleted file mode 100644
index f79c3b3e..00000000
--- a/compiler/internal/projs/proj.go
+++ /dev/null
@@ -1,110 +0,0 @@
-/*
- * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package projs
-
-import (
-	"errors"
-	"path/filepath"
-	"syscall"
-)
-
-// -----------------------------------------------------------------------------
-
-type Proj = interface {
-	projObj()
-}
-
-type FilesProj struct {
-	Files []string
-}
-
-type PkgPathProj struct {
-	Path string
-}
-
-type DirProj struct {
-	Dir string
-}
-
-func (p *FilesProj) projObj()   {}
-func (p *PkgPathProj) projObj() {}
-func (p *DirProj) projObj()     {}
-
-// -----------------------------------------------------------------------------
-
-func ParseOne(args ...string) (proj Proj, next []string, err error) {
-	if len(args) == 0 {
-		return nil, nil, syscall.ENOENT
-	}
-	arg := args[0]
-	if isFile(arg) {
-		n := 1
-		for n < len(args) && isFile(args[n]) {
-			n++
-		}
-		return &FilesProj{Files: args[:n]}, args[n:], nil
-	}
-	if isLocal(arg) {
-		return &DirProj{Dir: arg}, args[1:], nil
-	}
-	return &PkgPathProj{Path: arg}, args[1:], nil
-}
-
-func isFile(fname string) bool {
-	n := len(filepath.Ext(fname))
-	return n > 1
-}
-
-func isLocal(ns string) bool {
-	if len(ns) > 0 {
-		switch c := ns[0]; c {
-		case '/', '\\', '.':
-			return true
-		default:
-			return len(ns) >= 2 && ns[1] == ':' && ('A' <= c && c <= 'Z' || 'a' <= c && c <= 'z')
-		}
-	}
-	return false
-}
-
-// -----------------------------------------------------------------------------
-
-func ParseAll(args ...string) (projs []Proj, err error) {
-	var hasFiles, hasNotFiles bool
-	for {
-		proj, next, e := ParseOne(args...)
-		if e != nil {
-			if hasFiles && hasNotFiles {
-				return nil, ErrMixedFilesProj
-			}
-			return
-		}
-		if _, ok := proj.(*FilesProj); ok {
-			hasFiles = true
-		} else {
-			hasNotFiles = true
-		}
-		projs = append(projs, proj)
-		args = next
-	}
-}
-
-var (
-	ErrMixedFilesProj = errors.New("mixed files project")
-)
-
-// -----------------------------------------------------------------------------
diff --git a/compiler/internal/typeparams/normalize.go b/compiler/internal/typeparams/normalize.go
deleted file mode 100644
index 93c80fdc..00000000
--- a/compiler/internal/typeparams/normalize.go
+++ /dev/null
@@ -1,218 +0,0 @@
-// Copyright 2021 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 typeparams
-
-import (
-	"errors"
-	"fmt"
-	"go/types"
-	"os"
-	"strings"
-)
-
-//go:generate go run copytermlist.go
-
-const debug = false
-
-var ErrEmptyTypeSet = errors.New("empty type set")
-
-// StructuralTerms returns a slice of terms representing the normalized
-// structural type restrictions of a type parameter, if any.
-//
-// Structural type restrictions of a type parameter are created via
-// non-interface types embedded in its constraint interface (directly, or via a
-// chain of interface embeddings). For example, in the declaration
-//
-//	type T[P interface{~int; m()}] int
-//
-// the structural restriction of the type parameter P is ~int.
-//
-// With interface embedding and unions, the specification of structural type
-// restrictions may be arbitrarily complex. For example, consider the
-// following:
-//
-//	type A interface{ ~string|~[]byte }
-//
-//	type B interface{ int|string }
-//
-//	type C interface { ~string|~int }
-//
-//	type T[P interface{ A|B; C }] int
-//
-// In this example, the structural type restriction of P is ~string|int: A|B
-// expands to ~string|~[]byte|int|string, which reduces to ~string|~[]byte|int,
-// which when intersected with C (~string|~int) yields ~string|int.
-//
-// StructuralTerms computes these expansions and reductions, producing a
-// "normalized" form of the embeddings. A structural restriction is normalized
-// if it is a single union containing no interface terms, and is minimal in the
-// sense that removing any term changes the set of types satisfying the
-// constraint. It is left as a proof for the reader that, modulo sorting, there
-// is exactly one such normalized form.
-//
-// Because the minimal representation always takes this form, StructuralTerms
-// returns a slice of tilde terms corresponding to the terms of the union in
-// the normalized structural restriction. An error is returned if the
-// constraint interface is invalid, exceeds complexity bounds, or has an empty
-// type set. In the latter case, StructuralTerms returns ErrEmptyTypeSet.
-//
-// StructuralTerms makes no guarantees about the order of terms, except that it
-// is deterministic.
-func StructuralTerms(tparam *types.TypeParam) ([]*types.Term, error) {
-	constraint := tparam.Constraint()
-	if constraint == nil {
-		return nil, fmt.Errorf("%s has nil constraint", tparam)
-	}
-	iface, _ := constraint.Underlying().(*types.Interface)
-	if iface == nil {
-		return nil, fmt.Errorf("constraint is %T, not *types.Interface", constraint.Underlying())
-	}
-	return InterfaceTermSet(iface)
-}
-
-// InterfaceTermSet computes the normalized terms for a constraint interface,
-// returning an error if the term set cannot be computed or is empty. In the
-// latter case, the error will be ErrEmptyTypeSet.
-//
-// See the documentation of StructuralTerms for more information on
-// normalization.
-func InterfaceTermSet(iface *types.Interface) ([]*types.Term, error) {
-	return computeTermSet(iface)
-}
-
-// UnionTermSet computes the normalized terms for a union, returning an error
-// if the term set cannot be computed or is empty. In the latter case, the
-// error will be ErrEmptyTypeSet.
-//
-// See the documentation of StructuralTerms for more information on
-// normalization.
-func UnionTermSet(union *types.Union) ([]*types.Term, error) {
-	return computeTermSet(union)
-}
-
-func computeTermSet(typ types.Type) ([]*types.Term, error) {
-	tset, err := computeTermSetInternal(typ, make(map[types.Type]*termSet), 0)
-	if err != nil {
-		return nil, err
-	}
-	if tset.terms.isEmpty() {
-		return nil, ErrEmptyTypeSet
-	}
-	if tset.terms.isAll() {
-		return nil, nil
-	}
-	var terms []*types.Term
-	for _, term := range tset.terms {
-		terms = append(terms, types.NewTerm(term.tilde, term.typ))
-	}
-	return terms, nil
-}
-
-// A termSet holds the normalized set of terms for a given type.
-//
-// The name termSet is intentionally distinct from 'type set': a type set is
-// all types that implement a type (and includes method restrictions), whereas
-// a term set just represents the structural restrictions on a type.
-type termSet struct {
-	complete bool
-	terms    termlist
-}
-
-func indentf(depth int, format string, args ...interface{}) {
-	fmt.Fprintf(os.Stderr, strings.Repeat(".", depth)+format+"\n", args...)
-}
-
-func computeTermSetInternal(t types.Type, seen map[types.Type]*termSet, depth int) (res *termSet, err error) {
-	if t == nil {
-		panic("nil type")
-	}
-
-	if debug {
-		indentf(depth, "%s", t.String())
-		defer func() {
-			if err != nil {
-				indentf(depth, "=> %s", err)
-			} else {
-				indentf(depth, "=> %s", res.terms.String())
-			}
-		}()
-	}
-
-	const maxTermCount = 100
-	if tset, ok := seen[t]; ok {
-		if !tset.complete {
-			return nil, fmt.Errorf("cycle detected in the declaration of %s", t)
-		}
-		return tset, nil
-	}
-
-	// Mark the current type as seen to avoid infinite recursion.
-	tset := new(termSet)
-	defer func() {
-		tset.complete = true
-	}()
-	seen[t] = tset
-
-	switch u := t.Underlying().(type) {
-	case *types.Interface:
-		// The term set of an interface is the intersection of the term sets of its
-		// embedded types.
-		tset.terms = allTermlist
-		for i := 0; i < u.NumEmbeddeds(); i++ {
-			embedded := u.EmbeddedType(i)
-			if _, ok := embedded.Underlying().(*types.TypeParam); ok {
-				return nil, fmt.Errorf("invalid embedded type %T", embedded)
-			}
-			tset2, err := computeTermSetInternal(embedded, seen, depth+1)
-			if err != nil {
-				return nil, err
-			}
-			tset.terms = tset.terms.intersect(tset2.terms)
-		}
-	case *types.Union:
-		// The term set of a union is the union of term sets of its terms.
-		tset.terms = nil
-		for i := 0; i < u.Len(); i++ {
-			t := u.Term(i)
-			var terms termlist
-			switch t.Type().Underlying().(type) {
-			case *types.Interface:
-				tset2, err := computeTermSetInternal(t.Type(), seen, depth+1)
-				if err != nil {
-					return nil, err
-				}
-				terms = tset2.terms
-			case *types.TypeParam, *types.Union:
-				// A stand-alone type parameter or union is not permitted as union
-				// term.
-				return nil, fmt.Errorf("invalid union term %T", t)
-			default:
-				if t.Type() == types.Typ[types.Invalid] {
-					continue
-				}
-				terms = termlist{{t.Tilde(), t.Type()}}
-			}
-			tset.terms = tset.terms.union(terms)
-			if len(tset.terms) > maxTermCount {
-				return nil, fmt.Errorf("exceeded max term count %d", maxTermCount)
-			}
-		}
-	case *types.TypeParam:
-		panic("unreachable")
-	default:
-		// For all other types, the term set is just a single non-tilde term
-		// holding the type itself.
-		if u != types.Typ[types.Invalid] {
-			tset.terms = termlist{{false, t}}
-		}
-	}
-	return tset, nil
-}
-
-// under is a facade for the go/types internal function of the same name. It is
-// used by typeterm.go.
-func under(t types.Type) types.Type {
-	return t.Underlying()
-}
diff --git a/compiler/internal/typeparams/termlist.go b/compiler/internal/typeparams/termlist.go
deleted file mode 100644
index cbd12f80..00000000
--- a/compiler/internal/typeparams/termlist.go
+++ /dev/null
@@ -1,163 +0,0 @@
-// Copyright 2021 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.
-
-// Code generated by copytermlist.go DO NOT EDIT.
-
-package typeparams
-
-import (
-	"bytes"
-	"go/types"
-)
-
-// A termlist represents the type set represented by the union
-// t1 ∪ y2 ∪ ... tn of the type sets of the terms t1 to tn.
-// A termlist is in normal form if all terms are disjoint.
-// termlist operations don't require the operands to be in
-// normal form.
-type termlist []*term
-
-// allTermlist represents the set of all types.
-// It is in normal form.
-var allTermlist = termlist{new(term)}
-
-// String prints the termlist exactly (without normalization).
-func (xl termlist) String() string {
-	if len(xl) == 0 {
-		return "∅"
-	}
-	var buf bytes.Buffer
-	for i, x := range xl {
-		if i > 0 {
-			buf.WriteString(" | ")
-		}
-		buf.WriteString(x.String())
-	}
-	return buf.String()
-}
-
-// isEmpty reports whether the termlist xl represents the empty set of types.
-func (xl termlist) isEmpty() bool {
-	// If there's a non-nil term, the entire list is not empty.
-	// If the termlist is in normal form, this requires at most
-	// one iteration.
-	for _, x := range xl {
-		if x != nil {
-			return false
-		}
-	}
-	return true
-}
-
-// isAll reports whether the termlist xl represents the set of all types.
-func (xl termlist) isAll() bool {
-	// If there's a 𝓤 term, the entire list is 𝓤.
-	// If the termlist is in normal form, this requires at most
-	// one iteration.
-	for _, x := range xl {
-		if x != nil && x.typ == nil {
-			return true
-		}
-	}
-	return false
-}
-
-// norm returns the normal form of xl.
-func (xl termlist) norm() termlist {
-	// Quadratic algorithm, but good enough for now.
-	// TODO(gri) fix asymptotic performance
-	used := make([]bool, len(xl))
-	var rl termlist
-	for i, xi := range xl {
-		if xi == nil || used[i] {
-			continue
-		}
-		for j := i + 1; j < len(xl); j++ {
-			xj := xl[j]
-			if xj == nil || used[j] {
-				continue
-			}
-			if u1, u2 := xi.union(xj); u2 == nil {
-				// If we encounter a 𝓤 term, the entire list is 𝓤.
-				// Exit early.
-				// (Note that this is not just an optimization;
-				// if we continue, we may end up with a 𝓤 term
-				// and other terms and the result would not be
-				// in normal form.)
-				if u1.typ == nil {
-					return allTermlist
-				}
-				xi = u1
-				used[j] = true // xj is now unioned into xi - ignore it in future iterations
-			}
-		}
-		rl = append(rl, xi)
-	}
-	return rl
-}
-
-// union returns the union xl ∪ yl.
-func (xl termlist) union(yl termlist) termlist {
-	return append(xl, yl...).norm()
-}
-
-// intersect returns the intersection xl ∩ yl.
-func (xl termlist) intersect(yl termlist) termlist {
-	if xl.isEmpty() || yl.isEmpty() {
-		return nil
-	}
-
-	// Quadratic algorithm, but good enough for now.
-	// TODO(gri) fix asymptotic performance
-	var rl termlist
-	for _, x := range xl {
-		for _, y := range yl {
-			if r := x.intersect(y); r != nil {
-				rl = append(rl, r)
-			}
-		}
-	}
-	return rl.norm()
-}
-
-// equal reports whether xl and yl represent the same type set.
-func (xl termlist) equal(yl termlist) bool {
-	// TODO(gri) this should be more efficient
-	return xl.subsetOf(yl) && yl.subsetOf(xl)
-}
-
-// includes reports whether t ∈ xl.
-func (xl termlist) includes(t types.Type) bool {
-	for _, x := range xl {
-		if x.includes(t) {
-			return true
-		}
-	}
-	return false
-}
-
-// supersetOf reports whether y ⊆ xl.
-func (xl termlist) supersetOf(y *term) bool {
-	for _, x := range xl {
-		if y.subsetOf(x) {
-			return true
-		}
-	}
-	return false
-}
-
-// subsetOf reports whether xl ⊆ yl.
-func (xl termlist) subsetOf(yl termlist) bool {
-	if yl.isEmpty() {
-		return xl.isEmpty()
-	}
-
-	// each term x of xl must be a subset of yl
-	for _, x := range xl {
-		if !yl.supersetOf(x) {
-			return false // x is not a subset yl
-		}
-	}
-	return true
-}
diff --git a/compiler/internal/typeparams/typeterm.go b/compiler/internal/typeparams/typeterm.go
deleted file mode 100644
index 7350bb70..00000000
--- a/compiler/internal/typeparams/typeterm.go
+++ /dev/null
@@ -1,169 +0,0 @@
-// Copyright 2021 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.
-
-// Code generated by copytermlist.go DO NOT EDIT.
-
-package typeparams
-
-import "go/types"
-
-// A term describes elementary type sets:
-//
-//	 ∅:  (*term)(nil)     == ∅                      // set of no types (empty set)
-//	 𝓤:  &term{}          == 𝓤                      // set of all types (𝓤niverse)
-//	 T:  &term{false, T}  == {T}                    // set of type T
-//	~t:  &term{true, t}   == {t' | under(t') == t}  // set of types with underlying type t
-type term struct {
-	tilde bool // valid if typ != nil
-	typ   types.Type
-}
-
-func (x *term) String() string {
-	switch {
-	case x == nil:
-		return "∅"
-	case x.typ == nil:
-		return "𝓤"
-	case x.tilde:
-		return "~" + x.typ.String()
-	default:
-		return x.typ.String()
-	}
-}
-
-// equal reports whether x and y represent the same type set.
-func (x *term) equal(y *term) bool {
-	// easy cases
-	switch {
-	case x == nil || y == nil:
-		return x == y
-	case x.typ == nil || y.typ == nil:
-		return x.typ == y.typ
-	}
-	// ∅ ⊂ x, y ⊂ 𝓤
-
-	return x.tilde == y.tilde && types.Identical(x.typ, y.typ)
-}
-
-// union returns the union x ∪ y: zero, one, or two non-nil terms.
-func (x *term) union(y *term) (_, _ *term) {
-	// easy cases
-	switch {
-	case x == nil && y == nil:
-		return nil, nil // ∅ ∪ ∅ == ∅
-	case x == nil:
-		return y, nil // ∅ ∪ y == y
-	case y == nil:
-		return x, nil // x ∪ ∅ == x
-	case x.typ == nil:
-		return x, nil // 𝓤 ∪ y == 𝓤
-	case y.typ == nil:
-		return y, nil // x ∪ 𝓤 == 𝓤
-	}
-	// ∅ ⊂ x, y ⊂ 𝓤
-
-	if x.disjoint(y) {
-		return x, y // x ∪ y == (x, y) if x ∩ y == ∅
-	}
-	// x.typ == y.typ
-
-	// ~t ∪ ~t == ~t
-	// ~t ∪  T == ~t
-	//  T ∪ ~t == ~t
-	//  T ∪  T ==  T
-	if x.tilde || !y.tilde {
-		return x, nil
-	}
-	return y, nil
-}
-
-// intersect returns the intersection x ∩ y.
-func (x *term) intersect(y *term) *term {
-	// easy cases
-	switch {
-	case x == nil || y == nil:
-		return nil // ∅ ∩ y == ∅ and ∩ ∅ == ∅
-	case x.typ == nil:
-		return y // 𝓤 ∩ y == y
-	case y.typ == nil:
-		return x // x ∩ 𝓤 == x
-	}
-	// ∅ ⊂ x, y ⊂ 𝓤
-
-	if x.disjoint(y) {
-		return nil // x ∩ y == ∅ if x ∩ y == ∅
-	}
-	// x.typ == y.typ
-
-	// ~t ∩ ~t == ~t
-	// ~t ∩  T ==  T
-	//  T ∩ ~t ==  T
-	//  T ∩  T ==  T
-	if !x.tilde || y.tilde {
-		return x
-	}
-	return y
-}
-
-// includes reports whether t ∈ x.
-func (x *term) includes(t types.Type) bool {
-	// easy cases
-	switch {
-	case x == nil:
-		return false // t ∈ ∅ == false
-	case x.typ == nil:
-		return true // t ∈ 𝓤 == true
-	}
-	// ∅ ⊂ x ⊂ 𝓤
-
-	u := t
-	if x.tilde {
-		u = under(u)
-	}
-	return types.Identical(x.typ, u)
-}
-
-// subsetOf reports whether x ⊆ y.
-func (x *term) subsetOf(y *term) bool {
-	// easy cases
-	switch {
-	case x == nil:
-		return true // ∅ ⊆ y == true
-	case y == nil:
-		return false // x ⊆ ∅ == false since x != ∅
-	case y.typ == nil:
-		return true // x ⊆ 𝓤 == true
-	case x.typ == nil:
-		return false // 𝓤 ⊆ y == false since y != 𝓤
-	}
-	// ∅ ⊂ x, y ⊂ 𝓤
-
-	if x.disjoint(y) {
-		return false // x ⊆ y == false if x ∩ y == ∅
-	}
-	// x.typ == y.typ
-
-	// ~t ⊆ ~t == true
-	// ~t ⊆ T == false
-	//  T ⊆ ~t == true
-	//  T ⊆  T == true
-	return !x.tilde || y.tilde
-}
-
-// disjoint reports whether x ∩ y == ∅.
-// x.typ and y.typ must not be nil.
-func (x *term) disjoint(y *term) bool {
-	if debug && (x.typ == nil || y.typ == nil) {
-		panic("invalid argument(s)")
-	}
-	ux := x.typ
-	if y.tilde {
-		ux = under(ux)
-	}
-	uy := y.typ
-	if x.tilde {
-		uy = under(uy)
-	}
-	return !types.Identical(ux, uy)
-}
diff --git a/compiler/internal/typeutil/map.go b/compiler/internal/typeutil/map.go
deleted file mode 100644
index 028d5b5c..00000000
--- a/compiler/internal/typeutil/map.go
+++ /dev/null
@@ -1,525 +0,0 @@
-// 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.
-
-// Package typeutil defines various utilities for types, such as Map,
-// a mapping from types.Type to interface{} values.
-package typeutil
-
-import (
-	"bytes"
-	"fmt"
-	"go/types"
-	"reflect"
-
-	"github.com/goplus/llgo/compiler/internal/aliases"
-	"github.com/goplus/llgo/compiler/internal/typeparams"
-)
-
-// Map is a hash-table-based mapping from types (types.Type) to
-// arbitrary interface{} values.  The concrete types that implement
-// the Type interface are pointers.  Since they are not canonicalized,
-// == cannot be used to check for equivalence, and thus we cannot
-// simply use a Go map.
-//
-// Just as with map[K]V, a nil *Map is a valid empty map.
-//
-// Not thread-safe.
-type Map struct {
-	hasher Hasher             // shared by many Maps
-	table  map[uint32][]entry // maps hash to bucket; entry.key==nil means unused
-	length int                // number of map entries
-}
-
-// entry is an entry (key/value association) in a hash bucket.
-type entry struct {
-	key   types.Type
-	value interface{}
-}
-
-// SetHasher sets the hasher used by Map.
-//
-// All Hashers are functionally equivalent but contain internal state
-// used to cache the results of hashing previously seen types.
-//
-// A single Hasher created by MakeHasher() may be shared among many
-// Maps.  This is recommended if the instances have many keys in
-// common, as it will amortize the cost of hash computation.
-//
-// A Hasher may grow without bound as new types are seen.  Even when a
-// type is deleted from the map, the Hasher never shrinks, since other
-// types in the map may reference the deleted type indirectly.
-//
-// Hashers are not thread-safe, and read-only operations such as
-// Map.Lookup require updates to the hasher, so a full Mutex lock (not a
-// read-lock) is require around all Map operations if a shared
-// hasher is accessed from multiple threads.
-//
-// If SetHasher is not called, the Map will create a private hasher at
-// the first call to Insert.
-func (m *Map) SetHasher(hasher Hasher) {
-	m.hasher = hasher
-}
-
-// Delete removes the entry with the given key, if any.
-// It returns true if the entry was found.
-func (m *Map) Delete(key types.Type) bool {
-	if m != nil && m.table != nil {
-		hash := m.hasher.Hash(key)
-		bucket := m.table[hash]
-		for i, e := range bucket {
-			if e.key != nil && types.Identical(key, e.key) {
-				// We can't compact the bucket as it
-				// would disturb iterators.
-				bucket[i] = entry{}
-				m.length--
-				return true
-			}
-		}
-	}
-	return false
-}
-
-// At returns the map entry for the given key.
-// The result is nil if the entry is not present.
-func (m *Map) At(key types.Type) interface{} {
-	if m != nil && m.table != nil {
-		for _, e := range m.table[m.hasher.Hash(key)] {
-			if e.key != nil && types.Identical(key, e.key) {
-				return e.value
-			}
-		}
-	}
-	return nil
-}
-
-// Set sets the map entry for key to val,
-// and returns the previous entry, if any.
-func (m *Map) Set(key types.Type, value interface{}) (prev interface{}) {
-	if m.table != nil {
-		hash := m.hasher.Hash(key)
-		bucket := m.table[hash]
-		var hole *entry
-		for i, e := range bucket {
-			if e.key == nil {
-				hole = &bucket[i]
-			} else if types.Identical(key, e.key) {
-				prev = e.value
-				bucket[i].value = value
-				return
-			}
-		}
-
-		if hole != nil {
-			*hole = entry{key, value} // overwrite deleted entry
-		} else {
-			m.table[hash] = append(bucket, entry{key, value})
-		}
-	} else {
-		if m.hasher.memo == nil {
-			m.hasher = MakeHasher()
-		}
-		hash := m.hasher.Hash(key)
-		m.table = map[uint32][]entry{hash: {entry{key, value}}}
-	}
-
-	m.length++
-	return
-}
-
-// Len returns the number of map entries.
-func (m *Map) Len() int {
-	if m != nil {
-		return m.length
-	}
-	return 0
-}
-
-// Iterate calls function f on each entry in the map in unspecified order.
-//
-// If f should mutate the map, Iterate provides the same guarantees as
-// Go maps: if f deletes a map entry that Iterate has not yet reached,
-// f will not be invoked for it, but if f inserts a map entry that
-// Iterate has not yet reached, whether or not f will be invoked for
-// it is unspecified.
-func (m *Map) Iterate(f func(key types.Type, value interface{})) {
-	if m != nil {
-		for _, bucket := range m.table {
-			for _, e := range bucket {
-				if e.key != nil {
-					f(e.key, e.value)
-				}
-			}
-		}
-	}
-}
-
-// Keys returns a new slice containing the set of map keys.
-// The order is unspecified.
-func (m *Map) Keys() []types.Type {
-	keys := make([]types.Type, 0, m.Len())
-	m.Iterate(func(key types.Type, _ interface{}) {
-		keys = append(keys, key)
-	})
-	return keys
-}
-
-func (m *Map) toString(values bool) string {
-	if m == nil {
-		return "{}"
-	}
-	var buf bytes.Buffer
-	fmt.Fprint(&buf, "{")
-	sep := ""
-	m.Iterate(func(key types.Type, value interface{}) {
-		fmt.Fprint(&buf, sep)
-		sep = ", "
-		fmt.Fprint(&buf, key)
-		if values {
-			fmt.Fprintf(&buf, ": %q", value)
-		}
-	})
-	fmt.Fprint(&buf, "}")
-	return buf.String()
-}
-
-// String returns a string representation of the map's entries.
-// Values are printed using fmt.Sprintf("%v", v).
-// Order is unspecified.
-func (m *Map) String() string {
-	return m.toString(true)
-}
-
-// KeysString returns a string representation of the map's key set.
-// Order is unspecified.
-func (m *Map) KeysString() string {
-	return m.toString(false)
-}
-
-////////////////////////////////////////////////////////////////////////
-// Hasher
-
-// A Hasher maps each type to its hash value.
-// For efficiency, a hasher uses memoization; thus its memory
-// footprint grows monotonically over time.
-// Hashers are not thread-safe.
-// Hashers have reference semantics.
-// Call MakeHasher to create a Hasher.
-type Hasher struct {
-	memo map[types.Type]uint32
-
-	// ptrMap records pointer identity.
-	ptrMap map[interface{}]uint32
-
-	// sigTParams holds type parameters from the signature being hashed.
-	// Signatures are considered identical modulo renaming of type parameters, so
-	// within the scope of a signature type the identity of the signature's type
-	// parameters is just their index.
-	//
-	// Since the language does not currently support referring to uninstantiated
-	// generic types or functions, and instantiated signatures do not have type
-	// parameter lists, we should never encounter a second non-empty type
-	// parameter list when hashing a generic signature.
-	sigTParams *types.TypeParamList
-}
-
-// MakeHasher returns a new Hasher instance.
-func MakeHasher() Hasher {
-	return Hasher{
-		memo:       make(map[types.Type]uint32),
-		ptrMap:     make(map[interface{}]uint32),
-		sigTParams: nil,
-	}
-}
-
-// Hash computes a hash value for the given type t such that
-// Identical(t, t') => Hash(t) == Hash(t').
-func (h Hasher) Hash(t types.Type) uint32 {
-	hash, ok := h.memo[t]
-	if !ok {
-		hash = h.hashFor(t)
-		h.memo[t] = hash
-	}
-	return hash
-}
-
-// hashString computes the Fowler–Noll–Vo hash of s.
-func hashString(s string) uint32 {
-	var h uint32
-	for i := 0; i < len(s); i++ {
-		h ^= uint32(s[i])
-		h *= 16777619
-	}
-	return h
-}
-
-func HashSig(h Hasher, t *types.Signature) uint32 {
-	var hash uint32 = 9091
-	if t.Variadic() {
-		hash *= 8863
-	}
-
-	// Use a separate hasher for types inside of the signature, where type
-	// parameter identity is modified to be (index, constraint). We must use a
-	// new memo for this hasher as type identity may be affected by this
-	// masking. For example, in func[T any](*T), the identity of *T depends on
-	// whether we are mapping the argument in isolation, or recursively as part
-	// of hashing the signature.
-	//
-	// We should never encounter a generic signature while hashing another
-	// generic signature, but defensively set sigTParams only if h.mask is
-	// unset.
-	tparams := t.TypeParams()
-	if h.sigTParams == nil && tparams.Len() != 0 {
-		h = Hasher{
-			// There may be something more efficient than discarding the existing
-			// memo, but it would require detecting whether types are 'tainted' by
-			// references to type parameters.
-			memo: make(map[types.Type]uint32),
-			// Re-using ptrMap ensures that pointer identity is preserved in this
-			// hasher.
-			ptrMap:     h.ptrMap,
-			sigTParams: tparams,
-		}
-	}
-
-	for i := 0; i < tparams.Len(); i++ {
-		tparam := tparams.At(i)
-		hash += 7 * h.Hash(tparam.Constraint())
-	}
-
-	return hash + 3*h.hashTuple(t.Params()) + 5*h.hashTuple(t.Results())
-}
-
-// hashFor computes the hash of t.
-func (h Hasher) hashFor(t types.Type) uint32 {
-	// See Identical for rationale.
-	switch t := t.(type) {
-	case *types.Basic:
-		return uint32(t.Kind())
-
-	case *aliases.Alias:
-		return h.Hash(t.Underlying())
-
-	case *types.Array:
-		return 9043 + 2*uint32(t.Len()) + 3*h.Hash(t.Elem())
-
-	case *types.Slice:
-		return 9049 + 2*h.Hash(t.Elem())
-
-	case *types.Struct:
-		var hash uint32 = 9059
-		for i, n := 0, t.NumFields(); i < n; i++ {
-			f := t.Field(i)
-			if f.Anonymous() {
-				hash += 8861
-			}
-			hash += hashString(t.Tag(i))
-			hash += hashString(f.Name()) // (ignore f.Pkg)
-			hash += h.Hash(f.Type())
-		}
-		return hash
-
-	case *types.Pointer:
-		return 9067 + 2*h.Hash(t.Elem())
-
-	case *types.Signature:
-		return HashSig(h, t)
-
-	case *types.Union:
-		return h.hashUnion(t)
-
-	case *types.Interface:
-		// Interfaces are identical if they have the same set of methods, with
-		// identical names and types, and they have the same set of type
-		// restrictions. See go/types.identical for more details.
-		var hash uint32 = 9103
-
-		// Hash methods.
-		for i, n := 0, t.NumMethods(); i < n; i++ {
-			// Method order is not significant.
-			// Ignore m.Pkg().
-			m := t.Method(i)
-			// Use shallow hash on method signature to
-			// avoid anonymous interface cycles.
-			hash += 3*hashString(m.Name()) + 5*h.shallowHash(m.Type())
-		}
-
-		// Hash type restrictions.
-		terms, err := typeparams.InterfaceTermSet(t)
-		// if err != nil t has invalid type restrictions.
-		if err == nil {
-			hash += h.hashTermSet(terms)
-		}
-
-		return hash
-
-	case *types.Map:
-		return 9109 + 2*h.Hash(t.Key()) + 3*h.Hash(t.Elem())
-
-	case *types.Chan:
-		return 9127 + 2*uint32(t.Dir()) + 3*h.Hash(t.Elem())
-
-	case *types.Named:
-		hash := h.hashPtr(t.Obj())
-		targs := t.TypeArgs()
-		for i := 0; i < targs.Len(); i++ {
-			targ := targs.At(i)
-			hash += 2 * h.Hash(targ)
-		}
-		return hash
-
-	case *types.TypeParam:
-		return h.hashTypeParam(t)
-
-	case *types.Tuple:
-		return h.hashTuple(t)
-
-	case interface{ Hash(h Hasher) uint32 }:
-		return t.Hash(h)
-	}
-
-	panic(fmt.Sprintf("%T: %v", t, t))
-}
-
-func (h Hasher) hashTuple(tuple *types.Tuple) uint32 {
-	// See go/types.identicalTypes for rationale.
-	n := tuple.Len()
-	hash := 9137 + 2*uint32(n)
-	for i := 0; i < n; i++ {
-		hash += 3 * h.Hash(tuple.At(i).Type())
-	}
-	return hash
-}
-
-func (h Hasher) hashUnion(t *types.Union) uint32 {
-	// Hash type restrictions.
-	terms, err := typeparams.UnionTermSet(t)
-	// if err != nil t has invalid type restrictions. Fall back on a non-zero
-	// hash.
-	if err != nil {
-		return 9151
-	}
-	return h.hashTermSet(terms)
-}
-
-func (h Hasher) hashTermSet(terms []*types.Term) uint32 {
-	hash := 9157 + 2*uint32(len(terms))
-	for _, term := range terms {
-		// term order is not significant.
-		termHash := h.Hash(term.Type())
-		if term.Tilde() {
-			termHash *= 9161
-		}
-		hash += 3 * termHash
-	}
-	return hash
-}
-
-// hashTypeParam returns a hash of the type parameter t, with a hash value
-// depending on whether t is contained in h.sigTParams.
-//
-// If h.sigTParams is set and contains t, then we are in the process of hashing
-// a signature, and the hash value of t must depend only on t's index and
-// constraint: signatures are considered identical modulo type parameter
-// renaming. To avoid infinite recursion, we only hash the type parameter
-// index, and rely on types.Identical to handle signatures where constraints
-// are not identical.
-//
-// Otherwise the hash of t depends only on t's pointer identity.
-func (h Hasher) hashTypeParam(t *types.TypeParam) uint32 {
-	if h.sigTParams != nil {
-		i := t.Index()
-		if i >= 0 && i < h.sigTParams.Len() && t == h.sigTParams.At(i) {
-			return 9173 + 3*uint32(i)
-		}
-	}
-	return h.hashPtr(t.Obj())
-}
-
-// hashPtr hashes the pointer identity of ptr. It uses h.ptrMap to ensure that
-// pointers values are not dependent on the GC.
-func (h Hasher) hashPtr(ptr interface{}) uint32 {
-	if hash, ok := h.ptrMap[ptr]; ok {
-		return hash
-	}
-	hash := uint32(reflect.ValueOf(ptr).Pointer())
-	h.ptrMap[ptr] = hash
-	return hash
-}
-
-// shallowHash computes a hash of t without looking at any of its
-// element Types, to avoid potential anonymous cycles in the types of
-// interface methods.
-//
-// When an unnamed non-empty interface type appears anywhere among the
-// arguments or results of an interface method, there is a potential
-// for endless recursion. Consider:
-//
-//	type X interface { m() []*interface { X } }
-//
-// The problem is that the Methods of the interface in m's result type
-// include m itself; there is no mention of the named type X that
-// might help us break the cycle.
-// (See comment in go/types.identical, case *Interface, for more.)
-func (h Hasher) shallowHash(t types.Type) uint32 {
-	// t is the type of an interface method (Signature),
-	// its params or results (Tuples), or their immediate
-	// elements (mostly Slice, Pointer, Basic, Named),
-	// so there's no need to optimize anything else.
-	switch t := t.(type) {
-	case *aliases.Alias:
-		return h.shallowHash(t.Underlying())
-
-	case *types.Signature:
-		var hash uint32 = 604171
-		if t.Variadic() {
-			hash *= 971767
-		}
-		// The Signature/Tuple recursion is always finite
-		// and invariably shallow.
-		return hash + 1062599*h.shallowHash(t.Params()) + 1282529*h.shallowHash(t.Results())
-
-	case *types.Tuple:
-		n := t.Len()
-		hash := 9137 + 2*uint32(n)
-		for i := 0; i < n; i++ {
-			hash += 53471161 * h.shallowHash(t.At(i).Type())
-		}
-		return hash
-
-	case *types.Basic:
-		return 45212177 * uint32(t.Kind())
-
-	case *types.Array:
-		return 1524181 + 2*uint32(t.Len())
-
-	case *types.Slice:
-		return 2690201
-
-	case *types.Struct:
-		return 3326489
-
-	case *types.Pointer:
-		return 4393139
-
-	case *types.Union:
-		return 562448657
-
-	case *types.Interface:
-		return 2124679 // no recursion here
-
-	case *types.Map:
-		return 9109
-
-	case *types.Chan:
-		return 9127
-
-	case *types.Named:
-		return h.hashPtr(t.Obj())
-
-	case *types.TypeParam:
-		return h.hashPtr(t.Obj())
-	}
-	panic(fmt.Sprintf("shallowHash: %T: %v", t, t))
-}