title: Disambiguate associated type in struct
body: <p>I am trying to run this</p>
  
  <pre><code>use std::collections::BTreeSet;
  
  pub struct IntoIter&lt;T&gt; {
      iter: BTreeSet&lt;T&gt;::IntoIter,
  }
  
  fn main() {}
  </code></pre>
  
  <p><a href="https://play.rust-lang.org/?gist=6a495e05c71f9373c9ff94ec677ac67e&amp;version=stable" rel="nofollow noreferrer">Playground</a></p>
  
  <p>This fails with</p>
  
  <pre class="lang-none prettyprint-override"><code>error[E0223]: ambiguous associated type
   --&gt; src/main.rs:4:11
    |
  4 |     iter: BTreeSet&lt;T&gt;::IntoIter,
    |           ^^^^^^^^^^^^^^^^^^^^^ ambiguous associated type
    |
  </code></pre>
  
  <p>Why is the associated type ambiguous?</p>