FastCharSequence breaks EL (gatling-snapshot)

1.Maiha.scala

import io.gatling.core.Predef._
import io.gatling.http.Predef._

class Maiha extends Simulation {
  val top =
    exec(http("gatling.io")
      .get("/")
      .check(regex("""href="(.*?)"""").saveAs("url")) // should be "/assets/images/favicon.ico"
    )
    .exec(http("1st link")
      .get("/${url}")  // this builds "/io.gatling.core.util.FastCharSequence@73a658d1"
      .check(status.is(200))
    )

  val scn = scenario("once").exec(top)
  val prt = http.baseURL("http://gatling.io")
  setUp(scn.inject(atOnceUsers(1))).protocols(prt)
}

2.log(snapshot)

./bin/gatling.sh -nr -s Maiha

(snip)

Request:
1st link: KO status.is(200), but actually found 404
=========================
Session:
Session(once,3481976182196121905-0,Map(url -> io.gatling.core.util.FastCharSequence@1b9acccd, gatling.http.cache.expireStore -> Map(http://g\
atling.io/ -> 1411369997760), gatling.http.cache.lastModifiedStore -> Map(http://gatling.io/ -> Wed, 17 Sep 2014 06:18:53 GMT), gatling.http\
.referer -> http://gatling.io/io.gatling.core.util.FastCharSequence@1b9acccd, gatling.http.cookies -> CookieJar(Map())),1411369397347,49,KO,\
List(),<function1>)
=========================
HTTP request:
GET http://gatling.io/io.gatling.core.util.FastCharSequence@1b9acccd
headers=
Referer: http://gatling.io/
Connection: keep-alive
Host: gatling.io

3.patch.scala

diff --git a/gatling-core/src/main/scala/io/gatling/core/util/FastCharSequence.scala b/gatling-core/src/main/scala/io/gatling/core/util/FastC~
index 3ce8ca1..301db87 100644
--- a/gatling-core/src/main/scala/io/gatling/core/util/FastCharSequence.scala
+++ b/gatling-core/src/main/scala/io/gatling/core/util/FastCharSequence.scala
@@ -32,4 +32,6 @@ class FastCharSequence(chars: Array[Char], offset: Int, count: Int) extends Char
   def charAt(index: Int): Char = chars(offset + index)

   def subSequence(start: Int, end: Int): CharSequence = new FastCharSequence(chars, offset + start, end - start)
+
+  override def toString: String = String.valueOf(chars, offset, count)
 }

4.patched

./bin/gatling.sh -nr -s Maiha

(snip)

=========================
HTTP request:
GET http://gatling.io//assets/images/favicon.ico
headers=

(snip)

> gatling.io                                               (OK=1      KO=0     )
> 1st link                                                 (OK=1      KO=0     )