<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/63787>63787</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang-tidy readability-make-member-function-const suggests a change that breaks runtime behavior
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          stingray-11
      </td>
    </tr>
</table>

<pre>
    I have the following code.  There is a generic template function, and a specialized version to handle nullptr_t.  The generic one modifies the object that it's part of (non-const), while the specialized version does not.  clang-tidy thus produces a "readability-make-member-function-const" warning suggesting to add const to the end of the nullptr_t version.

This seems right, but it breaks runtime behavior.  At runtime, calling Equals(nullptr_t) will result in the generic version being selected rather than the nullptr_t specialized version. I'm not _entirely_ sure that this isn't a compiler bug, but both GCC and Clang behave this way.

I'm running Ubuntu 23.04 with GCC 12.2, and clang/clang-tidy 15.0.7
```
    template<typename T>
 [[nodiscard]] std::string Equals(const std::string& key, const T& val)
 {
        return key+" = "+AddParam(val);
    }

 [[nodiscard]] std::string Equals(const std::string& key, std::nullptr_t val)
    {
        return IsNull(key);
    }
```

Right now the only way to solve this is to add `// NOLINT(*-make-member-function-const)` after the nullptr_t function.  
</pre>
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