<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/128691>128691</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang assert: "Assertion `getDepthAndIndex(NewParam).first == 0 && "Unexpected template parameter depth"' failed."
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang:frontend
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          hokein
      </td>
    </tr>
</table>

<pre>
    https://godbolt.org/z/TPjf1YYY3

A regression from https://github.com/llvm/llvm-project/pull/111143

```
template <typename = void>
class NewDeleteAllocator;

template <>
struct NewDeleteAllocator<> {
  template <typename>
  NewDeleteAllocator();
};

template <typename>
struct NewDeleteAllocator : NewDeleteAllocator<> {
  using NewDeleteAllocator<>::NewDeleteAllocator;
};

void test() { NewDeleteAllocator abc; }
```
</pre>
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