<blockquote>
<p dir="auto">Issue originally made by <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/trusktr/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/trusktr">@trusktr</a></p>
</blockquote>
<h3 dir="auto">Bug information</h3>
<ul dir="auto">
<li><strong>Babel version:</strong> 6.7.4</li>
</ul>
<h3 dir="auto">Input code</h3>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="class Bar {
  constructor(arg1, arg2) {console.log(arg1, arg2)}
}

class Foo extends Bar {
    constructor(mountPoint, _motorHtmlScene) {
        if (_motorHtmlScene) super({}, _motorHtmlScene)
        else super()
    }
}"><pre class="notranslate"><code class="notranslate">class Bar {
  constructor(arg1, arg2) {console.log(arg1, arg2)}
}

class Foo extends Bar {
    constructor(mountPoint, _motorHtmlScene) {
        if (_motorHtmlScene) super({}, _motorHtmlScene)
        else super()
    }
}
</code></pre></div>
<h3 dir="auto">Description</h3>
<p dir="auto"><a href="https://goo.gl/KDEHEV" rel="nofollow">Simple example</a> that causes the error in the Babel repl.</p>
<blockquote>
<p dir="auto">Issue originally made by <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/DPOH-VAR/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/DPOH-VAR">@DPOH-VAR</a></p>
</blockquote>
<h3 dir="auto">Bug information</h3>
<ul dir="auto">
<li><strong>Babel version:</strong> 6.11.4</li>
<li><strong>Node version:</strong> 6.2.2</li>
<li><strong>npm version:</strong> 3.3.12</li>
</ul>
<h3 dir="auto">Input code</h3>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="class B{}
class A extends B{
  constructor(track){
    if (track !== undefined) super(track);
    else super();
  }
}"><pre class="notranslate"><code class="notranslate">class B{}
class A extends B{
  constructor(track){
    if (track !== undefined) super(track);
    else super();
  }
}
</code></pre></div>
<h3 dir="auto">Description</h3>
<p dir="auto"><code class="notranslate">Cannot read property 'operator' of null</code>  code:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="class B{}
class A extends B{
  constructor(track){
    if (track !== undefined) super(track);
    else super();
  }
}"><pre class="notranslate"><code class="notranslate">class B{}
class A extends B{
  constructor(track){
    if (track !== undefined) super(track);
    else super();
  }
}
</code></pre></div>
<p dir="auto">But this code works fine:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="class B{}
class A extends B{
  constructor(track){
    if (track !== undefined) {
      super(track);
    } else {
      super();
    }
  }
}"><pre class="notranslate"><code class="notranslate">class B{}
class A extends B{
  constructor(track){
    if (track !== undefined) {
      super(track);
    } else {
      super();
    }
  }
}
</code></pre></div>