}
		}
		return "UNSAFEPTR???"
	case "chan int":
		c := key.Interface().(chan int)
		for i := range chans {
			if c == chans[i] {
				return fmt.Sprintf("CHAN%d", i)
			}
		}
		return "CHAN???"
	default:
		return fmt.Sprint(key)
	}
}

var (
	ints  [3]int
	chans = makeChans()
	pin   runtime.Pinner
)

func makeChans() []chan int {

	{name: "pointer", format: "package main; var x «*»int"},
	{name: "func", format: "package main; var x «func()»int", scope: true},
	{name: "chan", format: "package main; var x «chan »int"},
	{name: "chan2", format: "package main; var x «<-chan »int"},
	{name: "interface", format: "package main; var x «interface { M() «int» }»", scope: true, scopeMultiplier: 2}, // Scopes: InterfaceType, FuncType

func Ranger[T any]() (*Sender[T], *Receiver[T]) {
	c := make(chan T)
	d := make(chan bool)
	s := &Sender[T]{values: c, done: d}
	r := &Receiver[T]{values: c, done: d}
	runtime.SetFinalizer(r, r.finalize)
	return s, r
}

// A sender is used to send values to a Receiver.
type Sender[T any] struct {
	values chan<- T
	done <-chan bool
}

// Send sends a value to the receiver. It returns whether any more

func Ranger[T any]() (*Sender[T], *Receiver[T]) {
	c := make(chan T)
	d := make(chan bool)
	s := &Sender[T]{values: c, done: d}
	r := &Receiver[T]{values: c, done: d}
	runtime.SetFinalizer(r, r.finalize)
	return s, r
}

// A sender is used to send values to a Receiver.
type Sender[T any] struct {
	values chan<- T
	done   <-chan bool
}

// Send sends a value to the receiver. It returns whether any more

func Ranger[T any]() (*Sender[T], *Receiver[T]) {
	c := make(chan T)
	d := make(chan bool)
	s := &Sender[T]{values: c, done: d}
	r := &Receiver[T]{values: c, done: d}
	runtime.SetFinalizer(r, r.finalize)
	return s, r
}

// A sender is used to send values to a Receiver.
type Sender[T any] struct {
	values chan<- T
	done <-chan bool
}

// Send sends a value to the receiver. It returns whether any more

		randx -= 1000000
	}
	return randx % n
}

type Chan struct {
	sc, rc chan int // send and recv chan
	sv, rv int      // send and recv seq
}

var (
	nproc      int
	nprocLock  sync.Mutex
	cval       int
	end        int = 10000
	totr, tots int
	totLock    sync.Mutex
	nc         *Chan
)

func init() {
	nc = new(Chan)
}

func changeNproc(adjust int) int {
	nprocLock.Lock()

// or the context is canceled, at which point the returned channel is closed.
func _Merge[Elem any](ctx context.Context, c1, c2 <-chan Elem) <-chan Elem {
	r := make(chan Elem)
	go func(ctx context.Context, c1, c2 <-chan Elem, r chan<- Elem) {
		defer close(r)
		for c1 != nil || c2 != nil {
			select {
			case <-ctx.Done():
				return
			case v1, ok := <-c1:
				if ok {
					r <- v1

func NewChan(dir ChanDir, elem Type) *Chan {
	return &Chan{dir: dir, elem: elem}
}

// 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 }

const W = 2    // channel buffering
var h [N]int   // marking of send/recv

func r(c chan int, m int) {
	for {
		select {
		case r := <-c:
			if h[r] != 1 {
				println("r",
					"m=", m,
					"r=", r,
					"h=", h[r])
				panic("fail")
			}
			h[r] = 2
		}
	}
}

func s(c chan int) {
	for n := 0; n < N; n++ {
		r := n
		if h[r] != 0 {
			println("s")
			panic("fail")
		}

func NewChan(dir ChanDir, elem Type) *Chan {
	return &Chan{dir: dir, elem: elem}
}

// 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 }