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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Class Proxy can't be extended"
href="https://bugs.webkit.org/show_bug.cgi?id=169040">169040</a>
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<th>Summary</th>
<td>Class Proxy can't be extended
</td>
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<th>Classification</th>
<td>Unclassified
</td>
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<th>Product</th>
<td>WebKit
</td>
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<th>Version</th>
<td>Safari Technology Preview
</td>
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<th>Hardware</th>
<td>Macintosh
</td>
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<th>OS</th>
<td>macOS 10.12
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>Normal
</td>
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<th>Priority</th>
<td>P2
</td>
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<th>Component</th>
<td>JavaScriptCore
</td>
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<th>Assignee</th>
<td>webkit-unassigned@lists.webkit.org
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<th>Reporter</th>
<td>dominic.szablewski@gmail.com
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<p>
<div>
<pre>A `Proxy` for a `class` can't be extended. When calling `SubClass extends ProxiedClass {}` JSC apparently tries to extend `Proxy` itself(?) instead of the underlying proxied class.
Test case:
<a href="http://phoboslab.org/files/bugs/safari-proxy-class.html">http://phoboslab.org/files/bugs/safari-proxy-class.html</a>
Tested in:
- Chrome (56.0.2924.87 (64-bit) macOS): success
- Firefox (51.0.1 (64-bit) macOS): success
- Safari TP (Release 24 (Safari 10.2, WebKit 12604.1.6)): fail</pre>
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