<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/132945>132945</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            std::expected link error
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          andrea-cassioli-maersk
      </td>
    </tr>
</table>

<pre>
    Compiling the following example
```
#include <expected>
#include <iostream>

int main() {
  std::expected<int, int> a;
  auto& x = a.value();
  std::cout << x << std::endl;
  return 0;
}
```

with
```
/opt/homebrew/opt/llvm@19/bin/clang++ -std=c++23 test-value.cpp
```

I get the following error
```
/opt/homebrew/opt/llvm@19/bin/clang++ -std=c++23 test-value.cpp 
Undefined symbols for architecture arm64:
  "std::__1::bad_expected_access<void>::what() const", referenced from:
      vtable for std::__1::bad_expected_access<int> in test-value-22e761.o
  "typeinfo for std::__1::bad_expected_access<void>", referenced from:
      typeinfo for std::__1::bad_expected_access<int> in test-value-22e761.o
  "vtable for std::__1::bad_expected_access<void>", referenced from:
      std::__1::bad_expected_access<void>::bad_expected_access[abi:ne190107]() in test-value-22e761.o
   NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
ld: symbol(s) not found for architecture arm64
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
```

some more info
```
âžœ  tmp /opt/homebrew/opt/llvm@19/bin/clang++ -v
Homebrew clang version 19.1.7
Target: arm64-apple-darwin23.6.0
Thread model: posix
InstalledDir: /opt/homebrew/Cellar/llvm/19.1.7_1/bin
Configuration file: /opt/homebrew/etc/clang/arm64-apple-darwin23.cfg
System configuration file directory: /opt/homebrew/etc/clang
User configuration file directory: /Users/xxxxxxx/.config/clang
```

Compiling with `clang` version 18 gives no error.

Not sure what is the issue. Hope someone can help.
</pre>
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