Bug 229479

Description Adriaan de Groot 2018-07-02 21:18:26 UTC

With 11.2-STABLE, using either base clang or clang50 from ports, this C++ program compiles, but fails to link:

```
  #include <string>
  static std::string foop() { return std::string(); }
  int main() {
    (void)(foop);
    return 0;
  }
```

The error message is

```
[adridg@beastie]$ c++ t.cpp 
/tmp/t-0b5183.o: In function `foop()':
t.cpp:(.text+0x20): undefined reference to `std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string()'
/usr/bin/ld: a.out: hidden symbol `_ZNSt3__112basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEC2Ev' isn't defined
/usr/bin/ld: final link failed: Nonrepresentable section on output
```

The same problem occurs with clang50 on 11-STABLE, and with (base) clang60 on 12-CURRENT from mid-june. The program compiles and links without issue with g++6 on 11-STABLE.

Removing the line `(void)(foop);` allows the program to link; it does generate one warning about an unused function, though.


**On Linux**: The program compiles and links with clang5 and clang6 on Linux using the default C++ library (e.g. `clang++ t.cpp`). I am told that it does **not** link when using libc++ (e.g. `clang++ -stdlib=libc++ t.cpp`). I have not been able to verify that, though