title: Typescript optional chaining error: Expression expected.ts(1109)
body: <p>I am trying to do optional chaining in Typescript + React Native.</p>
  
  <p>Let's say I have the following interfaces:</p>
  
  <pre><code>interface Bar {
    y: number
  }
  
  interface Foo {
    x?: Bar
  }
  </code></pre>
  
  <p>and I try to run the following:</p>
  
  <pre><code> const test: Foo = {x: {y: 3}};
   console.log(test.x?.y);
  </code></pre>
  
  <p>VSCode will show an error under the <code>?.</code> saying the following: <em>Expression expected.ts(1109)</em> </p>
  
  <p>Do you have any idea why this is happening or how should I fix it? Thanks.</p>