importcpp does not work with C++ free functions (works with C++ methods) and dynamic linking

[risuwwv]

Example

// test.cpp
// compiled with `g++ -o test.dll -shared test.cpp`
__declspec(dllexport) int addTwoIntegers(int a, int b)
{
  return a + b;
}

proc addTwoIntegers(a, b: cint): cint {.importcpp, dynlib: "test2.dll".}
echo addTwoIntegers(3, 7)

Current Output

# nim cpp interop2.nim
nimcache\interop2_d\@minterop2.nim.cpp: In function 'void NimMainModule()':
nimcache\interop2_d\@minterop2.nim.cpp:147:29: error: request for member 'Dl_436207617_' in '3', which is of non-class type 'int'
  147 |         int T2_ = ((int) 3).Dl_436207617_(((int) 7));
      |                             ^~~~~~~~~~~~~

Expected Output

Should compile as the same code works if C is used instead of C++.

Additional Information

• Issue importcpp does not work with C++ free functions (works with C++ methods) #12150 is related, but different because there seems to be no workaround in the dynamic linking case.
• I am still learning the language so if there is a workaround, I would be interested to know it.

$ nim -v
Nim Compiler Version 1.6.0 [Windows: amd64]
Compiled at 2021-10-19