}

func (d *DotNode) Copy() Node {
	return d.tr.newDot(d.Pos)
}

// NilNode holds the special identifier 'nil' representing an untyped nil constant.
type NilNode struct {
	NodeType
	Pos
	tr *Tree
}

func (t *Tree) newNil(pos Pos) *NilNode {
	return &NilNode{tr: t, NodeType: NodeNil, Pos: pos}
}

func (n *NilNode) Type() NodeType {
	// Override method on embedded NodeType for API compatibility.

	case *parse.DotNode:
		return dot
	case *parse.FieldNode:
		return s.evalFieldNode(dot, n, nil, missingVal)
	case *parse.IdentifierNode:
		return s.evalFunction(dot, n, n, nil, missingVal)
	case *parse.NilNode:
		// NilNode is handled in evalArg, the only place that calls here.
		s.errorf("evalEmptyInterface: nil (can't happen)")
	case *parse.NumberNode:
		return s.idealConstant(n)
	case *parse.StringNode:

# CL 130620043 text/template: add back pointer to Nodes for better error generation, Rob Pike <******@****.***>
pkg text/template/parse, type DotNode struct, embedded NodeType
pkg text/template/parse, type NilNode struct, embedded NodeType
pkg text/template/parse, method (*BranchNode) Copy() Node
pkg text/template/parse, method (*IdentifierNode) SetTree(*Tree) *IdentifierNode
pkg html/template, type Error struct, Node parse.Node

		{"(*IfNode).String", Method, 0},
		{"(*ListNode).Copy", Method, 0},
		{"(*ListNode).CopyList", Method, 0},
		{"(*ListNode).String", Method, 0},
		{"(*NilNode).Copy", Method, 1},
		{"(*NilNode).String", Method, 1},
		{"(*NilNode).Type", Method, 1},
		{"(*NumberNode).Copy", Method, 0},
		{"(*NumberNode).String", Method, 0},
		{"(*PipeNode).Copy", Method, 0},
		{"(*PipeNode).CopyPipe", Method, 0},

pkg text/template/parse, method (*IdentifierNode) SetPos(Pos) *IdentifierNode
pkg text/template/parse, method (*NilNode) Copy() Node
pkg text/template/parse, method (*NilNode) String() string
pkg text/template/parse, method (*NilNode) Type() NodeType
pkg text/template/parse, method (*Tree) ErrorContext(Node) (string, string)
pkg text/template/parse, method (ActionNode) Position() Pos