Does range over a nil slice have defined behavior?

[Brad Fitzpatrick]

Should range over a nil slice have defined behavior?

I don't see it in the spec:  (unless I missed it)

http://golang.org/doc/go_spec.html#For_statements

I would guess it might be safe, as the length of a nil slice is defined to be zero.

Worth calling out explicitly?

[Steven]

I'd say that:

A "for" statement with a "range" clause iterates through all entries of an array, slice, string or map, or values received on a channel.

and

The length and capacity of a nil slice, map, or channel are 0.

mean that a nil slice has 0 entries, and therefore the range clause will produce no iterations. Since the spec doesn't distinguish between nil and non-nil in the range clause, and it does specify the number of elements of a nil slice, an implementation that failed when ranging over a nil slice would be in violation of the spec.