Fix for aliasing bug, Ticket 8412

I just created a ticket which includes a patch for an aliasing bug that has bitten me several times. Can somebody take a look at it? It's a half a line of code and includes a test that shows the problem. Ticket #8412 (http://dev.rubyonrails.org/ticket/8412)

Mike Mangino
http://www.elevatedrails.com

Committed. Thanks Mike.

jeremy