title: Why is crossScalaVersion not scalaVersion?
body: <p><strong>build.sbt</strong></p>
  
  <pre><code>scalaVersion := "2.11.4"
  </code></pre>
  
  <p><strong>project/build.properties</strong></p>
  
  <pre><code>sbt.version=0.13.7
  </code></pre>
  
  <p>Then</p>
  
  <pre><code>&gt; show scalaVersion
  [info] 2.11.4
  &gt; show crossScalaVersions
  [info] List(2.10.4)
  &gt; inspect crossScalaVersions
  [info] Setting: scala.collection.Seq[java.lang.String] = List(2.10.4)
  [info] Description:
  [info]  The versions of Scala used when cross-building.
  [info] Provided by:
  [info]  */*:crossScalaVersions
  [info] Defined at:
  [info]  (sbt.Defaults) Defaults.scala:237
  [info] Delegates:
  [info]  *:crossScalaVersions
  [info]  {.}/*:crossScalaVersions
  [info]  */*:crossScalaVersions
  [info] Related:
  [info]  */*:crossScalaVersions
  </code></pre>
  
  <p>It seems like <code>crossScalaVersions</code> should be <code>List(2.11.4)</code>.</p>
  
  <p>Look at SBT's <a href="https://github.com/sbt/sbt/blob/0.13.7/main/src/main/scala/sbt/Defaults.scala#L237" rel="nofollow">source code</a>, that's also what I would think.</p>
  
  <pre><code>crossScalaVersions := Seq(scalaVersion.value)
  </code></pre>
  
  <p>Why doesn't <code>crossScalaVersions</code> correspond to <code>scalaVersion</code>?</p>