//     22  .  .  .  .  }
	//     23  .  .  .  }
	//     24  .  .  .  Body: *ast.BlockStmt {
	//     25  .  .  .  .  Lbrace: 3:13
	//     26  .  .  .  .  List: []ast.Stmt (len = 1) {
	//     27  .  .  .  .  .  0: *ast.ExprStmt {
	//     28  .  .  .  .  .  .  X: *ast.CallExpr {
	//     29  .  .  .  .  .  .  .  Fun: *ast.Ident {
	//     30  .  .  .  .  .  .  .  .  NamePos: 4:2
	//     31  .  .  .  .  .  .  .  .  Name: "println"

	case *BadStmt:
		// nothing to do

	case *DeclStmt:
		Walk(v, n.Decl)

	case *EmptyStmt:
		// nothing to do

	case *LabeledStmt:
		Walk(v, n.Label)
		Walk(v, n.Stmt)

	case *ExprStmt:
		Walk(v, n.X)

	case *SendStmt:
		Walk(v, n.Chan)
		Walk(v, n.Value)

	case *IncDecStmt:
		Walk(v, n.X)

	case *AssignStmt:
		walkList(v, n.Lhs)
		walkList(v, n.Rhs)

		w.node(n.Elem)

	// statements
	case *EmptyStmt: // nothing to do

	case *LabeledStmt:
		w.node(n.Label)
		w.node(n.Stmt)

	case *BlockStmt:
		w.stmtList(n.List)

	case *ExprStmt:
		w.node(n.X)

	case *SendStmt:
		w.node(n.Chan)
		w.node(n.Value)

	case *DeclStmt:
		w.declList(n.DeclList)

	case *AssignStmt:
		w.node(n.Lhs)
		if n.Rhs != nil {

	case *ast.BadStmt, *ast.EmptyStmt:
		// ignore

	case *ast.DeclStmt:
		check.declStmt(s.Decl)

	case *ast.LabeledStmt:
		check.hasLabel = true
		check.stmt(ctxt, s.Stmt)

	case *ast.ExprStmt:
		// spec: "With the exception of specific built-in functions,
		// function and method calls and receive operations can appear
		// in statement context. Such statements may be parenthesized."
		var x operand

			return
		}

		contentType := expfmt.Negotiate(r.Header)
		w.Header().Set("Content-Type", string(contentType))

		enc := expfmt.NewEncoder(w, contentType)
		for _, mf := range mfs {
			if err := enc.Encode(mf); err != nil {
				// client may disconnect for any reasons
				// we do not have to log this.
				return
			}
		}
		if closer, ok := enc.(expfmt.Closer); ok {
			closer.Close()
		}

	EmptyStmt struct {
		simpleStmt
	}

	LabeledStmt struct {
		Label *Name
		Stmt  Stmt
		stmt
	}

	BlockStmt struct {
		List   []Stmt
		Rbrace Pos
		stmt
	}

	ExprStmt struct {
		X Expr
		simpleStmt
	}

	SendStmt struct {
		Chan, Value Expr // Chan <- Value
		simpleStmt
	}

	DeclStmt struct {
		DeclList []Decl
		stmt
	}

	case token.INC, token.DEC:
		// increment or decrement
		s := &ast.IncDecStmt{x[0], p.pos, p.tok}
		p.next() // consume "++" or "--"
		return s
	}

	// expression
	return &ast.ExprStmt{x[0]}
}

func (p *parser) parseCallExpr() *ast.CallExpr {
	x := p.parseRhs()
	if call, isCall := x.(*ast.CallExpr); isCall {
		return call
	}
	p.errorExpected(x.Pos(), "function/method call")

		f.walk(&n.Value, ctxType, visit)

	case *ast.BadStmt:
	case *ast.DeclStmt:
		f.walk(n.Decl, ctxDecl, visit)
	case *ast.EmptyStmt:
	case *ast.LabeledStmt:
		f.walk(n.Stmt, ctxStmt, visit)
	case *ast.ExprStmt:
		f.walk(&n.X, ctxExpr, visit)
	case *ast.SendStmt:
		f.walk(&n.Chan, ctxExpr, visit)
		f.walk(&n.Value, ctxExpr, visit)
	case *ast.IncDecStmt:
		f.walk(&n.X, ctxExpr, visit)
	case *ast.AssignStmt:

		a.apply(n, "Decl", nil, n.Decl)

	case *ast.EmptyStmt:
		// nothing to do

	case *ast.LabeledStmt:
		a.apply(n, "Label", nil, n.Label)
		a.apply(n, "Stmt", nil, n.Stmt)

	case *ast.ExprStmt:
		a.apply(n, "X", nil, n.X)

	case *ast.SendStmt:
		a.apply(n, "Chan", nil, n.Chan)
		a.apply(n, "Value", nil, n.Value)

	case *ast.IncDecStmt:
		a.apply(n, "X", nil, n.X)

		case _Arrow:
			// lhs <- rhs
			s := new(SendStmt)
			s.pos = pos
			p.next()
			s.Chan = lhs
			s.Value = p.expr()
			return s

		default:
			// expr
			s := new(ExprStmt)
			s.pos = lhs.Pos()
			s.X = lhs
			return s
		}
	}

	// expr_list
	switch p.tok {
	case _Assign, _Define:
		pos := p.pos()
		var op Operator
		if p.tok == _Define {