http://play.golang.org/p/sgdJPamWRd

package main

import "regexp"

var r1 = regexp.MustCompile("x{0,3}")
var r2 = regexp.MustCompile("x{,3}")

func main() {
    println(r1.MatchString(""), r2.MatchString(""))
}

prints 'true false' but I expected 'true true'.

It is entirely possible that I have forgotten what x{,3} means,
but I thought it meant x{0,3}.  It is not listed on
http://code.google.com/p/re2/wiki/Syntax, so maybe
it should be a syntax error?