// Does this type implement GobEncoder?
	if ut.externalEnc != 0 {
		return newGobEncoderType(name), nil
	}
	var err error
	var type0, type1 gobType
	defer func() {
		if err != nil {
			delete(types, rt)
		}
	}()
	// Install the top-level type before the subtypes (e.g. struct before
	// fields) so recursive types can be constructed safely.
	switch t := rt; t.Kind() {

		panic(msg)
	}
	w.buf.WriteString("<" + msg + ">")
}

func (w *typeWriter) typ(typ Type) {
	if w.seen[typ] {
		w.error("cycle to " + goTypeName(typ))
		return
	}
	w.seen[typ] = true
	defer delete(w.seen, typ)

	switch t := typ.(type) {
	case nil:
		w.error("nil")

	case *Basic:
		// exported basic types go into package unsafe
		// (currently this is just unsafe.Pointer)

		panic(msg)
	}
	w.buf.WriteString("<" + msg + ">")
}

func (w *typeWriter) typ(typ Type) {
	if w.seen[typ] {
		w.error("cycle to " + goTypeName(typ))
		return
	}
	w.seen[typ] = true
	defer delete(w.seen, typ)

	switch t := typ.(type) {
	case nil:
		w.error("nil")

	case *Basic:
		// exported basic types go into package unsafe
		// (currently this is just unsafe.Pointer)

	// Handle each case slightly differently; we just group them together
	// because they have shared preconditions.
	newCtx := curCtx
	switch ev.typ {
	case go122.EvGoDestroy:
		// This goroutine is exiting itself.
		delete(o.gStates, curCtx.G)
		newCtx.G = NoGoroutine
	case go122.EvGoStop:
		// Goroutine stopped (yielded). It's runnable but not running on this M.
		state.status = go122.GoRunnable
		newCtx.G = NoGoroutine

			return
		}

		if check.recordTypes() {
			check.recordBuiltinType(call.Fun, makeSig(Typ[Int], x.typ, y.typ))
		}
		x.mode = value
		x.typ = Typ[Int]

	case _Delete:
		// delete(map_, key)
		// map_ must be a map type or a type parameter describing map types.
		// The key cannot be a type parameter for now.
		map_ := x.typ
		var key Type
		if !underIs(map_, func(u Type) bool {

			x = x.intersect(y)
			if x.absent() {
				x = VarLoc{}
				break
			}
		}

		// Delete if necessary, but not otherwise (in order to maximize sharing).
		if x.absent() {
			if !x0.absent() {
				blockChanged = true
				newState.Delete(k)
			}
			slotLocs[k] = VarLoc{}
			continue
		}
		if x != x0 {
			blockChanged = true

	}))
	res, err := cst.c.Get(cst.ts.URL)
	if err != nil {
		t.Fatal(err)
	}
	if _, err := io.Copy(io.Discard, res.Body); err != nil {
		t.Fatal(err)
	}
	res.Body.Close()
	delete(res.Header, "Date")
	delete(res.Header, "Content-Type")

	if want := (Header{"Foo": {"Bar"}}); !reflect.DeepEqual(res.Header, want) {
		t.Errorf("Header = %#v; want %#v", res.Header, want)
	}

	//
	// Example:
	//  var _ = complex(float32(1), float64(2))
	InvalidComplex

	// InvalidDelete occurs when the delete built-in function is called with a
	// first argument that is not a map.
	//
	// Example:
	//  func f() {
	//  	m := "hello"
	//  	delete(m, "e")
	//  }
	InvalidDelete

	// InvalidImag occurs when the imag built-in function is called with an

	t := fsTester{fsys: fsys}
	t.checkDir(".")
	t.checkOpen(".")
	found := make(map[string]bool)
	for _, dir := range t.dirs {
		found[dir] = true
	}
	for _, file := range t.files {
		found[file] = true
	}
	delete(found, ".")
	if len(expected) == 0 && len(found) > 0 {
		var list []string
		for k := range found {
			if k != "." {
				list = append(list, k)
			}
		}
		slices.Sort(list)
		if len(list) > 15 {

	_Clear:   {"clear", 1, false, statement},
	_Close:   {"close", 1, false, statement},
	_Complex: {"complex", 2, false, expression},
	_Copy:    {"copy", 2, false, statement},
	_Delete:  {"delete", 2, false, statement},
	_Imag:    {"imag", 1, false, expression},
	_Len:     {"len", 1, false, expression},
	_Make:    {"make", 1, true, expression},
	// To disable max/min, remove the next two lines.