spec: clarify range over nil values #1713
Description
This has now come up at least three times: http://groups.google.com/group/golang-nuts/browse_thread/thread/d9354cdd183cc3fc "The length of nil slice, map, and channel are 0. What's the expected behaviour of loop when the range expression evaluates to nil? " Rob: "I'm not certain this is well specified. That should be addressed."