<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/77104>77104</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [Clang] Can not friend a function in root namespace with non-void return type
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          Sh3Rm4n
      </td>
    </tr>
</table>

<pre>
    Compiler Explorer: https://godbolt.org/z/Gzhdo54W7

Clang is not able to friend a function, which lives in the root namespace. 

```cpp
#include <cstdint>

uint32_t friend_foo();

namespace n {
class bar {
    friend uint32_t ::friend_foo();
    void private_method() {}
};
}

uint32_t friend_foo() {
    n::bar b;
 b.private_method();
    return 0;
}
```

It has problems to swallow the `friend uint32_t ::friend_foo();` syntax. 

```
<source>:7:12: error: 'uint32_t' (aka 'unsigned int') is not a class, namespace, or enumeration
    7 |     friend uint32_t ::friend_foo();
      |   
```

Switching the return type to `void` removes the error. 

```diff
3c3
< uint32_t friend_foo();
---
> void friend_foo();
7c7
<     friend uint32_t ::friend_foo();
---
>     friend void ::friend_foo();
14c14
< uint32_t friend_foo() {
---
> void friend_foo() {
18,19d17
< 
<     return 0;
```

or moving the class and the function to the same namespace, so that the `::` prefix is not needed does remove the error.
</pre>
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