Colon token.Pos // position of ":"
		Value Expr
	}
)

// The direction of a channel type is indicated by a bit
// mask including one or both of the following constants.
type ChanDir int

const (
	SEND ChanDir = 1 << iota
	RECV
)

// A type is represented by a tree consisting of one
// or more of the following type-specific expression
// nodes.
type (

		value := TypeExpr(f, pkg, t.Elem())
		if key == nil || value == nil {
			return nil
		}
		return &ast.MapType{
			Key:   key,
			Value: value,
		}
	case *types.Chan:
		dir := ast.ChanDir(t.Dir())
		if t.Dir() == types.SendRecv {
			dir = ast.SEND | ast.RECV
		}
		value := TypeExpr(f, pkg, t.Elem())
		if value == nil {
			return nil
		}
		return &ast.ChanType{
			Dir:   dir,

	n.Chan = DefaultLit(n.Chan, nil)
	t := n.Chan.Type()
	if t == nil {
		return n
	}
	if !t.IsChan() {
		base.Errorf("invalid operation: %v (send to non-chan type %v)", n, t)
		return n
	}

	if !t.ChanDir().CanSend() {
		base.Errorf("invalid operation: %v (send to receive-only type %v)", n, t)
		return n
	}

	n.Value = AssignConv(n.Value, t.Elem(), "send")
	if n.Value.Type() == nil {
		return n
	}

		return types.NewPointer(r.typ())
	case sliceType:
		return types.NewSlice(r.typ())
	case arrayType:
		n := r.uint64()
		return types.NewArray(r.typ(), int64(n))
	case chanType:
		dir := chanDir(int(r.uint64()))
		return types.NewChan(dir, r.typ())
	case mapType:
		return types.NewMap(r.typ(), r.typ())
	case signatureType:
		r.currPkg = r.pkg()
		return r.signature(nil, nil, nil)

	case pkgbits.TypeTypeParam:
		return r.dict.tparams[r.Len()]

	case pkgbits.TypeArray:
		len := int64(r.Uint64())
		return types.NewArray(r.typ(), len)
	case pkgbits.TypeChan:
		dir := types.ChanDir(r.Len())
		return types.NewChan(dir, r.typ())
	case pkgbits.TypeMap:
		return types.NewMap(r.typ(), r.typ())
	case pkgbits.TypePointer:
		return types.NewPointer(r.typ())
	case pkgbits.TypeSignature:

// It panics if v's Kind is not [Chan] or
// v is a receive-only channel.
func (v Value) Close() {
	v.mustBe(Chan)
	v.mustBeExported()
	tt := (*chanType)(unsafe.Pointer(v.typ()))
	if ChanDir(tt.Dir)&SendDir == 0 {
		panic("reflect: close of receive-only channel")
	}

	chanclose(v.pointer())
}

// CanComplex reports whether [Value.Complex] can be used without panicking.

		return ir.OXXX, why
	}

	// 4. src is a bidirectional channel value, dst is a channel type,
	// src and dst have identical element types, and
	// either src or dst is not a named type.
	if src.IsChan() && src.ChanDir() == types.Cboth && dst.IsChan() {
		if types.Identical(src.Elem(), dst.Elem()) && (src.Sym() == nil || dst.Sym() == nil) {
			return ir.OCONVNOP, ""
		}
	}

	if t == nil {
		n.SetType(nil)
		return n
	}
	if !t.IsChan() {
		base.Errorf("invalid operation: %v (receive from non-chan type %v)", n, t)
		n.SetType(nil)
		return n
	}

	if !t.ChanDir().CanRecv() {
		base.Errorf("invalid operation: %v (receive from send-only type %v)", n, t)
		n.SetType(nil)
		return n
	}

	n.SetType(t.Elem())
	return n
}

// tcSPtr typechecks an OSPTR node.

	t := l.Type()
	if t == nil {
		n.SetType(nil)
		return n
	}
	if !t.IsChan() {
		base.Errorf("invalid operation: %v (non-chan type %v)", n, t)
		n.SetType(nil)
		return n
	}

	if !t.ChanDir().CanSend() {
		base.Errorf("invalid operation: %v (cannot close receive-only channel)", n)
		n.SetType(nil)
		return n
	}
	return n
}

// tcComplex typechecks an OCOMPLEX node.

			break
		}
		om := fmtsort.Sort(val)
		for _, m := range om {
			oneIteration(m.Key, m.Value)
		}
		return
	case reflect.Chan:
		if val.IsNil() {
			break
		}
		if val.Type().ChanDir() == reflect.SendDir {
			s.errorf("range over send-only channel %v", val)
			break
		}
		i := 0
		for ; ; i++ {
			elem, ok := val.Recv()
			if !ok {
				break
			}