title: Why am I getting a "No signature of method"" error when running the closure recursion example in the Groovy shell?
body: <p>I'm trying to experiment with the Groovy closure recursion example from <a href="http://groovy.codehaus.org/JN2515-Closures" rel="nofollow">http://groovy.codehaus.org/JN2515-Closures</a> .</p>
  
  <p>I saved the snippet in a file called recursionTest.groovy and loaded it in the shell, but I'm getting a "No signature of method error":</p>
  
  <pre><code>// recursionTest.groovy   
  
  def results = [];
  { a, b -&gt;
    results &lt;&lt; a
    a&lt;10 &amp;&amp; call(b, a+b)
  }(1,1)
  
  assert results == [1, 1, 2, 3, 5, 8, 13]
  
  
  groovy:000&gt; load recursionTest.groovy
  ===&gt; []
  ERROR groovy.lang.MissingMethodException:
  No signature of method: java.lang.Boolean.call() is applicable for argument types: (groovysh_evaluate$_run_closure1) values: [groovysh_evaluate$_run_closure1@6b7599cc]
  Possible solutions: wait(), any(), wait(long), and(java.lang.Boolean), each(groovy.lang.Closure), any(groovy.lang.Closure)
          at groovysh_evaluate.run (groovysh_evaluate:1)
          ...
  groovy:003&gt; 
  </code></pre>
  
  <p>What's going on?</p>