for i, arg := range args {
		switch a := arg.(type) {
		case nil:
			arg = "<nil>"
		case operand:
			panic("got operand instead of *operand")
		case *operand:
			arg = operandString(a, qf)
		case syntax.Pos:
			arg = a.String()
		case syntax.Expr:
			arg = ExprString(a)
		case []syntax.Expr:
			var buf strings.Builder
			buf.WriteByte('[')
			for i, x := range a {
				if i > 0 {

// commaerr   <expr> (               <mode>       of type <typ>)
//
// cgofunc    <expr> (<untyped kind> <mode>                    )
// cgofunc    <expr> (               <mode>       of type <typ>)
func operandString(x *operand, qf Qualifier) string {
	// special-case nil
	if isTypes2 {
		if x.mode == nilvalue {
			switch x.typ {
			case nil, Typ[Invalid]:
				return "nil (with invalid type)"
			case Typ[UntypedNil]:

	for i, arg := range args {
		switch a := arg.(type) {
		case nil:
			arg = "<nil>"
		case operand:
			panic("got operand instead of *operand")
		case *operand:
			arg = operandString(a, qf)
		case token.Pos:
			if fset != nil {
				arg = fset.Position(a).String()
			}
		case ast.Expr:
			arg = ExprString(a)
		case []ast.Expr:
			var buf bytes.Buffer
			buf.WriteByte('[')

// commaerr   <expr> (               <mode>       of type <typ>)
//
// cgofunc    <expr> (<untyped kind> <mode>                    )
// cgofunc    <expr> (               <mode>       of type <typ>)
func operandString(x *operand, qf Qualifier) string {
	// special-case nil
	if isTypes2 {
		if x.mode == nilvalue {
			switch x.typ {
			case nil, Typ[Invalid]:
				return "nil (with invalid type)"
			case Typ[UntypedNil]: