Actually No you can't. The mail in the trash is subject only. It looks for the server for the rest of the email. But of course there is nothing on the server because it was deleted. In my opinion this is not a small bug. This is a large problem.
Luckily for me, my old pc ran thunderbird. So the messages were saved in Thunderbird. I had to login to the old pc and keep it offline. Export the mail and then import the mail to another account then put it back on gmail. Otherwise, it just deletes all the mail on thunderbird because gmail has all those folders empty.