On the Common Terms page of the d20PFSRD website, the "Rest" section says:
The Pathfinder Core Rulebook is somewhat vague on the requirements of resting and sleeping […]
I found that this is true.
Is there any errata that addresses the argument about how elves sleep/trance/rest?
Their immunity to magic sleep seems to indicate that designer either forgot to mention that elves don’t sleep as humans do, or they mistakenly left that immunity from 3.5 re-design.