// comments on the same line before the next position.
func (p *printer) commentSizeBefore(next token.Position) int {
	// save/restore current p.commentInfo (p.nextComment() modifies it)
	defer func(info commentInfo) {
		p.commentInfo = info
	}(p.commentInfo)

	size := 0
	for p.commentBefore(next) {
		for _, c := range p.comment.List {
			size += len(c.Text)
		}
		p.nextComment()
	}
	return size