// until c is closed or the context is canceled, at which point the
// returned channel is closed.
func Filter[Elem any](ctx context.Context, c <-chan Elem, f func(Elem) bool) <-chan Elem {
	r := make(chan Elem)
	go func(ctx context.Context, c <-chan Elem, f func(Elem) bool, r chan<- Elem) {
		defer close(r)
		for {
			select {
			case <-ctx.Done():
				return
			case v, ok := <-c:
				if !ok {
					return

		~float32 | ~float64 |
		~string
}

type orderedSlice[Elem Ordered] []Elem

func (s orderedSlice[Elem]) Len() int { return len(s) }
func (s orderedSlice[Elem]) Less(i, j int) bool {
	if s[i] < s[j] {
		return true
	}
	isNaN := func(f Elem) bool { return f != f }
	if isNaN(s[i]) && !isNaN(s[j]) {
		return true
	}
	return false
}
func (s orderedSlice[Elem]) Swap(i, j int) { s[i], s[j] = s[j], s[i] }

// until c is closed or the context is canceled, at which point the
// returned channel is closed.
func _Filter[Elem any](ctx context.Context, c <-chan Elem, f func(Elem) bool) <-chan Elem {
	r := make(chan Elem)
	go func(ctx context.Context, c <-chan Elem, f func(Elem) bool, r chan<- Elem) {
		defer close(r)
		for {
			select {
			case <-ctx.Done():
				return
			case v, ok := <-c:
				if !ok {
					return

type sliceFn[Elem any] struct {
	s []Elem
	f func(Elem, Elem) bool
}

func (s sliceFn[Elem]) Len() int           { return len(s.s) }
func (s sliceFn[Elem]) Less(i, j int) bool { return s.f(s.s[i], s.s[j]) }
func (s sliceFn[Elem]) Swap(i, j int)      { s.s[i], s.s[j] = s.s[j], s.s[i] }

// SliceFn sorts the slice s according to the function f.
func SliceFn[Elem any](s []Elem, f func(Elem, Elem) bool) {
	Sort(sliceFn[Elem]{s, f})

// Dir returns the direction of channel c.
func (c *Chan) Dir() ChanDir { return c.dir }

// Elem returns the element type of channel c.
func (c *Chan) Elem() Type { return c.elem }

func (c *Chan) Underlying() Type { return c }

		newline   = "\n"
		tab       = "\t"
	)

	readModuleLine := func(elem []string) (Module, error) {
		if len(elem) != 2 && len(elem) != 3 {
			return Module{}, fmt.Errorf("expected 2 or 3 columns; got %d", len(elem))
		}
		version := elem[1]
		sum := ""
		if len(elem) == 3 {
			sum = elem[2]
		}
		return Module{
			Path:    elem[0],
			Version: version,
			Sum:     sum,
		}, nil
	}

	case reflect.Slice, reflect.Array:
		for i := 0; i < reflectValue.Len(); i++ {
			elem := reflectValue.Index(i)
			elemKey := elem.Interface()
			if elem.Kind() != reflect.Ptr && elem.CanAddr() {
				elemKey = elem.Addr().Interface()
			}

			if _, ok := loaded[elemKey]; ok {
				continue
			}
			loaded[elemKey] = true

// _Make makes a new set.
func _Make[Elem comparable]() _Set[Elem] {
	return _Set[Elem]{m: make(map[Elem]struct{})}
}

// Add adds an element to a set.
func (s _Set[Elem]) Add(v Elem) {
	s.m[v] = struct{}{}
}

// Delete removes an element from a set. If the element is not present
// in the set, this does nothing.
func (s _Set[Elem]) Delete(v Elem) {
	delete(s.m, v)
}

// Contains reports whether v is in the set.

func Filter[Elem any](s []Elem, f func(Elem) bool) []Elem {
	var r []Elem
	for _, v := range s {
		if f(v) {
			r = append(r, v)
		}
	}
	return r
}

// Max returns the maximum element in a slice of some ordered type.
// If the slice is empty it returns the zero value of the element type.
func SliceMax[Elem Ordered](s []Elem) Elem {
	if len(s) == 0 {
		var zero Elem
		return zero

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

type Elem struct{}

func (*Elem) Wait(callback func()) {}

type Base struct {
	elem [8]*Elem
}

var g_val = 1

func (s *Base) Do() *int {
	resp := &g_val
	for _, e := range s.elem {
		e.Wait(func() {
			*resp = 0
		})
	}
	return resp
}

type Sub struct {
	*Base
}