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.

	TRESULTS // multiple types; the result of calling a function or method, with a memory at the end.

	NTYPE
)

// ChanDir is whether a channel can send, receive, or both.
type ChanDir uint8

func (c ChanDir) CanRecv() bool { return c&Crecv != 0 }
func (c ChanDir) CanSend() bool { return c&Csend != 0 }

const (
	// types of channel
	// must match ../../../../reflect/type.go:/ChanDir
	Crecv ChanDir = 1 << 0
	Csend ChanDir = 1 << 1