title: PI constant is ambiguous
body: <p>Consider following code:</p>
  
  <pre><code>fn main() {
      let i = f32::consts::PI;
  }
  </code></pre>
  
  <p>With following error:</p>
  
  <pre><code>$ rustc --version
  rustc 1.0.0 (a59de37e9 2015-05-13) (built 2015-05-14)
  $ rustc -
  &lt;anon&gt;:2:13: 2:28 error: ambiguous associated type; specify the type using the syntax `&lt;f32 as Trait&gt;::consts` [E0223]
  &lt;anon&gt;:2     let i = f32::consts::PI;
                       ^~~~~~~~~~~~~~~
  error: aborting due to previous error
  </code></pre>
  
  <ol>
  <li>Why does it complain about an "associated type"? The only type I see here is <code>f32</code>, which is not associated.  </li>
  <li>Why is this ambigious? I clearly specified the <code>f32</code>.</li>
  <li>What is this <code>&lt;f32 as Trait&gt;::consts</code> syntax? I've never seen it before.</li>
  <li>And, obviously, what can I do to fix this error and get my variable set to PI?</li>
  </ol>