rtyp = ix.X
		if unpackParams {
			for _, arg := range ix.Indices {
				var par *ast.Ident
				switch arg := arg.(type) {
				case *ast.Ident:
					par = arg
				case *ast.BadExpr:
					// ignore - error already reported by parser
				case nil:
					check.error(ix.Orig, InvalidSyntaxTree, "parameterized receiver contains nil parameters")
				default:

	_, ok := expr.(*ast.BinaryExpr)
	return ok
}

func (p *printer) expr1(expr ast.Expr, prec1, depth int) {
	p.setPos(expr.Pos())

	switch x := expr.(type) {
	case *ast.BadExpr:
		p.print("BadExpr")

	case *ast.Ident:
		p.print(x)

	case *ast.BinaryExpr:
		if depth < 1 {
			p.internalError("depth < 1:", depth)
			depth = 1
		}
		p.binaryExpr(x, prec1, cutoff(x, depth), depth)

	old, found := check.untyped[x]
	if !found {
		return // nothing to do
	}

	// update operands of x if necessary
	switch x := x.(type) {
	case *syntax.BadExpr,
		*syntax.FuncLit,
		*syntax.CompositeLit,
		*syntax.IndexExpr,
		*syntax.SliceExpr,
		*syntax.AssertExpr,
		*syntax.ListExpr,
		//*syntax.StarExpr,
		*syntax.KeyValueExpr,
		*syntax.ArrayType,

		{"AssignStmt.Tok", Field, 0},
		{"AssignStmt.TokPos", Field, 0},
		{"Bad", Const, 0},
		{"BadDecl", Type, 0},
		{"BadDecl.From", Field, 0},
		{"BadDecl.To", Field, 0},
		{"BadExpr", Type, 0},
		{"BadExpr.From", Field, 0},
		{"BadExpr.To", Field, 0},
		{"BadStmt", Type, 0},
		{"BadStmt.From", Field, 0},
		{"BadStmt.To", Field, 0},
		{"BasicLit", Type, 0},
		{"BasicLit.Kind", Field, 0},

pkg go/ast, type BadDecl struct
pkg go/ast, type BadDecl struct, From token.Pos
pkg go/ast, type BadDecl struct, To token.Pos
pkg go/ast, type BadExpr struct
pkg go/ast, type BadExpr struct, From token.Pos
pkg go/ast, type BadExpr struct, To token.Pos
pkg go/ast, type BadStmt struct
pkg go/ast, type BadStmt struct, From token.Pos
pkg go/ast, type BadStmt struct, To token.Pos