This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
There are conversions that take place during the evaluation of the expression. "Widening", etc. The language specification talks about it in detail. But simply put, most things will be "widened" to the greater number of bits required and then the evaluation will take place.