func generate(absFile string) bool {
	src, err := os.ReadFile(absFile)
	if err != nil {
		log.Fatalf("generate: %s", err)
	}

	// Parse package clause
	filePkg, err := parser.ParseFile(token.NewFileSet(), "", src, parser.PackageClauseOnly)
	if err != nil {
		// Invalid package clause - ignore file.
		return true
	}

	g := &Generator{
		r:        bytes.NewReader(src),

	typeCacheBuckets = 256
	typeCacheAssoc   = 4
)

type typeCacheBucket struct {
	t [typeCacheAssoc]*_type
}

var typecache [typeCacheBuckets]typeCacheBucket

// dump a uint64 in a varint format parseable by encoding/binary.
func dumpint(v uint64) {
	var buf [10]byte
	var n int
	for v >= 0x80 {
		buf[n] = byte(v | 0x80)
		n++
		v >>= 7
	}
	buf[n] = byte(v)
	n++

	// come before the beginning of the named declaration and after the end
	// of the previous declaration.
	fset := token.NewFileSet()
	astFile, err := parser.ParseFile(fset, testDirectives, output, 0)
	if err != nil {
		t.Fatal(err)
	}

	prevEnd := 0
	for _, decl := range astFile.Decls {
		var name string
		switch d := decl.(type) {
		case *ast.FuncDecl:

	}
}

func generate(t *testing.T, filename string, write bool) {
	// parse src (cmd/compile/internal/types2)
	srcFilename := filepath.FromSlash(runtime.GOROOT() + srcDir + filename)
	file, err := parser.ParseFile(fset, srcFilename, nil, parser.ParseComments)
	if err != nil {
		t.Fatal(err)
	}

	// fix package name
	file.Name.Name = strings.ReplaceAll(file.Name.Name, "types2", "types")

	// rewrite AST as needed

	//
	// 	^(?P<name>/[^:]+):(?P<unit>[^:*/]+(?:[*/][^:*/]+)*)$
	//
	// The format splits the name into two components, separated by a colon: a path which always
	// starts with a /, and a machine-parseable unit. The name may contain any valid Unicode
	// codepoint in between / characters, but by convention will try to stick to lowercase
	// characters and hyphens. An example of such a path might be "/memory/heap/free".
	//

		}
		runes = append(runes, r)
	}
	return string(runes)
}

func checkFile(t *testing.T, filename string, src []byte) *types.Package {
	fset := token.NewFileSet()
	f, err := parser.ParseFile(fset, filename, src, 0)
	if err != nil {
		t.Fatal(err)
	}
	config := types.Config{
		Importer: importer.Default(),
	}
	pkg, err := config.Check("", fset, []*ast.File{f}, nil)
	if err != nil {

			}
			err = cmd.Run()
			if err != nil {
				return err
			}
			out, err := os.ReadFile(filepath.Join(dir, "_cgo_gotypes.go"))
			if err != nil {
				return err
			}
			cgo, err := parser.ParseFile(token.NewFileSet(), "cgo.go", out, 0)
			if err != nil {
				return err
			}
			for _, decl := range cgo.Decls {
				fn, ok := decl.(*ast.FuncDecl)
				if !ok {
					continue
				}

	}
	fn.add(stmtf("return false"))
	genFile.add(fn)

	// Remove unused imports and variables.
	buf := new(bytes.Buffer)
	fprint(buf, genFile)
	fset := token.NewFileSet()
	file, err := parser.ParseFile(fset, "", buf, parser.ParseComments)
	if err != nil {
		filename := fmt.Sprintf("%s_broken.go", arch.name)
		if err := os.WriteFile(filename, buf.Bytes(), 0644); err != nil {

	// Pass in the overlaid source if we have an overlay for this file.
	src, err := fsys.Open(filename)
	if err != nil {
		return err
	}
	defer src.Close()
	f, err := parser.ParseFile(testFileSet, filename, src, parser.ParseComments|parser.SkipObjectResolution)
	if err != nil {
		return err
	}
	for _, d := range f.Decls {
		n, ok := d.(*ast.FuncDecl)
		if !ok {
			continue
		}

package p

func A(func(any), ...any) {}
func B[T any](T)          {}

func _() {
	A(B, nil // syntax error: missing ',' before newline in argument list
}
`
	fset := token.NewFileSet()
	f, err := parser.ParseFile(fset, pkgName(src), src, 0)
	if err == nil {
		t.Fatal("expected syntax error")
	}

	var conf Config
	conf.Check(f.Name.Name, fset, []*ast.File{f}, nil) // must not panic
}