title: Dart - Param type int considered num during type checking in Android Studio 3.6.3
body: <p>The code below produces a type error of:</p>
  
  <p><code>"The argument type int can't be assigned to the parameter type num"</code></p>
  
  <p>Why is <code>sum</code> being considered a <code>num</code>, when it's defined as <code>int</code>?</p>
  
  <p>If I change <code>sum</code> from <code>int</code> to <code>var</code>, the error disappears.</p>
  
  <p>Can someone explain why this is happening?</p>
  
  <pre><code>abstract class ISomeInterface {
    void add&lt;T&gt;(T x);
  }
  
  class SomeClass implements ISomeInterface {
    int sum;
  
    @override
    void add&lt;int&gt;(int x) {
      sum = sum + x;
    }
  }
  </code></pre>