<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/126270>126270</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Clang does not diagnose an explicit specialization or partial specialization of initializer_list
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang:frontend,
            accepts-invalid
      </td>
    </tr>

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

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

<pre>
    According to the C++ standard (C++23 [initializer.list.syn] paragraph 2):

> If an explicit specialization or partial specialization of `initializer_list` is declared, the program is ill-formed.

It does not say "no diagnostic is required"; therefore, I think Clang must produce an error, but it does not. Example code:

```
#include <initializer_list>

template<>
class std::initializer_list<int> {};

template<typename T>
class std::initializer_list<T*> {};
```

Clang (current trunk version) accepts the code with `-std=c++23 -pedantic-errors`.
</pre>
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