spec: clarify evaluation order of "i, x[i] = range ..."
spec: clarify evaluation order of "i, x[i] = range ..."

Part of fix for issue 3464.

R=golang-dev, rsc, mirtchovski, iant, r
CC=golang-dev
http://codereview.appspot.com/6246045

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang