title: Scala 2.8: type inference of anonymous functions as default parameters
body: <p>In Scala 2.8.0 RC 2 this definition:</p>
  
  <pre><code>  def buttonGroup[T](values: Array[T], textProvider: T =&gt; String = (t: T =&gt; t.toString)) = ...
  </code></pre>
  
  <p>gives the error message: </p>
  
  <blockquote>
    <p>not found: value t</p>
  </blockquote>
  
  <pre><code>  def buttonGroup[T](values: Array[T], textProvider: T =&gt; String = (_.toString)) = ...
  </code></pre>
  
  <p>gives</p>
  
  <blockquote>
    <p>missing parameter type for expanded function ((x$1) => x$1{}.toString{}){}</p>
  </blockquote>
  
  <p>Only this works: </p>
  
  <pre><code> textProvider: T =&gt; String = (_:T).toString
  </code></pre>
  
  <p>Why? </p>