Type checked contain matcher coming in ScalaTest 3.0

gistfile1.scala

> console
[info] Compiling 1 Scala source to /Users/bv/nobkp/delus/redlady/target/scala-2.11/classes...
[info] Starting scala interpreter...
[info] 
import org.scalatest._
import org.scalactic._
import Matchers._
Welcome to Scala version 2.11.2 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_65).
Type in expressions to have them evaluated.
Type :help for more information.

scala> "all your base are belong to us" should contain ("base")
org.scalatest.exceptions.TestFailedException: "all your base are belong to us" did not contain element "base"
  at org.scalatest.MatchersHelper$.newTestFailedException(MatchersHelper.scala:160)
  at org.scalatest.Matchers$ShouldMethodHelper$.shouldMatcher(Matchers.scala:6808)
  at org.scalatest.Matchers$AnyShouldWrapper.should(Matchers.scala:6854)
  ... 43 elided

scala> import CheckedEquality._
import CheckedEquality._

scala> "all your base are belong to us" should contain ("base")
<console>:20: error: could not find implicit value for parameter typeClass1:
    org.scalactic.enablers.EvidenceThat[String]#CanBeContainedIn[String]
              "all your base are belong to us" should contain ("base")
                                               ^