Go range over uint8 slice?

EDIT This was due to a stupid error in my part, but the question is worth keeping around in case someone else does this.

I would hope that this works:

var xs []uint8
var x uint8
for x = range xs {

}

But I get the error:

cannot assign type int to x (type uint8) in range

i.e. (as I understand it) the range, even though it is operating on a slice of uint8, is trying to use int as the iterated value.

I have looked through the language spec, the relevant bit:

Range expression                          1st value          2nd value (if 2nd variable is present)

array or slice  a  [n]E, *[n]E, or []E    index    i  int    a[i]       E

so I would expect it to be E the 'parameterised type'*, in this case uint8 not int.

Have I grasped onto the wrong end of the stick? Is there a bit of documentation that I missed? Or can I really not iterate over a uint8 slice with a uint8 variable?

*I know it's not really a generic parameterised type.

range returns an index into a collection and possibly the value at that position:

> range keyword The range keyword allows you to iterate over items of a
> list like an array or a map. For understanding it, you could translate
> the range keyword to for each index of. When used with arrays and
> slices, it returns the integer index of the item.
(tutorial)

sample code:

package main

import "fmt"

func main() {
	var xs []uint8 = []uint8{255, 254, 253}
	var idx int
	var ui8 uint8
	for idx, ui8 = range xs {
		fmt.Println(idx, ui8)
	}
}

output:

0 255
1 254
2 253

P.S.:

Perhaps a look at Javascript will make Go's approach less strange:

% a = [255, 254, 253]
255,254,253
% for (x in a) { print(x, " ", a[x]); }
0 255
1 254
2 253