<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/155376>155376</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Error calling a function template after reinterpret_cast of a static variable
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

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

<pre>
    This program
```c++
template<auto E>
void test2() {
    ++*E;
}

template<typename T>
char test1() {
    static char a[16];
    static T& ref = *reinterpret_cast<T*>(a);
    test2<a>();
 test2<&ref>();
    return a[0];
}

int main() {
    return test1<int>();
}
```
is accepted in GCC and MSVC.

But Clang 20.1 rejects it with
```
<source>:11:5: error: no matching function for call to 'test2'
   11 |     test2<&ref>();
      |     ^~~~~~~~~~~
<source>:16:12: note: in instantiation of function template specialization 'test1<int>' requested here
   16 |     return test1<int>();
      | ^
<source>:2:6: note: candidate template ignored: invalid explicitly-specified argument for template parameter 'E'
    2 | void test2() {
      |      ^
```
Online demo: https://gcc.godbolt.org/z/o9WsvE33e

Clang trunk shows the same error in C++20 mode, but in C++23 mode, the program compiles fine but a linker error appears:
```
undefined reference to `test1()::a'
```
Online demo: https://gcc.godbolt.org/z/4Mzaczo3e

Original report: https://stackoverflow.com/q/79745946/7325599
</pre>
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