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    <head>
      <base href="https://bugs.webkit.org/" />
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - &quot;this&quot; missing after await in async arrow function"
   href="https://bugs.webkit.org/show_bug.cgi?id=166919">166919</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>&quot;this&quot; missing after await in async arrow function
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>WebKit
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>WebKit Nightly Build
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Unspecified
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Unspecified
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>Normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P2
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>JavaScriptCore
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>webkit-unassigned&#64;lists.webkit.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>hszhsh&#64;icloud.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>My test code is as follows.

function runSomething(callback) {
    callback();
}

class Test {
    testFunc() {
        this.prop = &quot;123&quot;;
        runSomething(async () =&gt; {
            console.log(&quot;callback &quot; + this.prop); // It's ok here
            await sleep(2);
            console.log(&quot;callback end &quot; + this.prop); // TypeError: undefined is not an object (evaluating 'this.prop')
        });
    }
}

let t = new Test();
t.testFunc();</pre>
        </div>
      </p>
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      <ul>
          <li>You are the assignee for the bug.</li>
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