title: No i32/f64 fallback when using pow()
body: <p>With the following:</p>
  
  <pre><code>4.pow(2)
  </code></pre>
  
  <p>I get:</p>
  
  <pre><code>error: no method named `pow` found for type `_` in the current scope
  </code></pre>
  
  <p>I have to be more explicit about it, e.g.:</p>
  
  <pre><code>4_i32.pow(2)
  </code></pre>
  
  <p>With floats, I get a similar problem (and solution), where:</p>
  
  <pre><code>4.0.powf(2.0)
  </code></pre>
  
  <p>Must also be explicit:</p>
  
  <pre><code>4.0_f64.powf(2.0)
  </code></pre>