Pybind fails to build with MSVC 19.16 in C++17 mode

[LeslieGerman]

Fails to build with MSVC 19.16.27034.0 in C++17

I used pybind v 2.4.3

cmake -G Ninja -DPYBIND11_CPP_STANDARD=/std:c++17 ..\src
ninja

Error:

D:\Libs\Pybind\2.4.3\src\include\pybind11/stl_bind.h(415): error C2893: Failed to specialize function template 'enable_if<_Test,Ty>::type pybind11::detail::vector_buffer(Class &)'
with
[
_Ty=void
]

No problem with the default c++14 mode.

Great library, BTW! 😃 👍

[YannickJadoul]

I can't reproduce this with pybind 2.5.0, Python 3.8, and MSVC 19.25.28614.0:

PS C:\Users\Yannick\pybind11\build> cmake .. -DPYBIND11_CPP_STANDARD=/std:c++17 -DPYTHON_EXECUTABLE=C:\Python38\python.exe               
-- Building for: Visual Studio 16 2019                                                                                                   
-- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.18363.                                                              
-- The CXX compiler identification is MSVC 19.25.28614.0                                                                                 
-- Check for working CXX compiler: E:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.25.28610/bin/Hostx64/x
64/cl.exe                                                                                                                                
-- Check for working CXX compiler: E:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.25.28610/bin/Hostx64/x
64/cl.exe -- works                                                                                                                       
-- Detecting CXX compiler ABI info                                                                                                       
-- Detecting CXX compiler ABI info - done                                                                                                
-- Detecting CXX compile features                                                                                                        
-- Detecting CXX compile features - done                                                                                                 
-- Found PythonInterp: C:/Python38/python.exe (found version "3.8.1")                                                                    
-- Found PythonLibs: C:/Python38/libs/python38.lib                                                                                       
-- Building tests WITHOUT Eigen                                                                                                          
-- Could NOT find Boost (missing: Boost_INCLUDE_DIR) (Required is at least version "1.56")                                               
-- Performing Test HAS_MSVC_GL_LTCG                                                                                                      
-- Performing Test HAS_MSVC_GL_LTCG - Success                                                                                            
-- LTO enabled                                                                                                                           
-- Catch not detected. Interpreter tests will be skipped. Install Catch headers manually or use `cmake -DDOWNLOAD_CATCH=1` to fetch them 
automatically.                                                                                                                           
-- Configuring done                                                                                                                      
-- Generating done                                                                                                                       
-- Build files have been written to: C:/Users/Yannick/pybind11/build                                                                     
PS C:\Users\Yannick\pybind11\build> cmake -build .                                                                                       
-- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.18363.                                                              
-- Building tests WITHOUT Eigen                                                                                                          
-- Could NOT find Boost (missing: Boost_INCLUDE_DIR) (Required is at least version "1.56")                                               
automatically.                                                                                                                           
-- pybind11 v2.5.dev1                                                                                                                    
-- Configuring done                                                                                                                      
-- Generating done                                                                                                                       
-- Build files have been written to: C:/Users/Yannick/pybind11/build                                                                     
> cmake --build . --target pytest                                                                      
Microsoft (R) Build Engine version 16.5.0+d4cbfca49 for .NET Framework                                                                   
Copyright (C) Microsoft Corporation. All rights reserved.                                                                                
                                                                                                                                         
  cross_module_gil_utils.vcxproj -> C:\Users\Yannick\pybind11\tests\cross_module_gil_utils.cp38-win_amd64.pyd                            
  pybind11_cross_module_tests.vcxproj -> C:\Users\Yannick\pybind11\tests\pybind11_cross_module_tests.cp38-win_amd64.pyd                  
  pybind11_tests.vcxproj -> C:\Users\Yannick\pybind11\tests\pybind11_tests.cp38-win_amd64.pyd                                            
  ------ pybind11_tests.cp38-win_amd64.pyd file size: 15982592 (no change)                   

[...]
                                            
  ============================= test session starts =============================                                                        
  platform win32 -- Python 3.8.1, pytest-5.3.5, py-1.8.1, pluggy-0.13.1                                                                  
  rootdir: C:\Users\Yannick\pybind11\tests, inifile: pytest.ini                                                                          
  plugins: cov-2.8.1, lazy-fixture-0.6.3                                                                                                 
  collected 344 items

[...]

  ======================= 314 passed, 30 skipped in 5.67s =======================                                                        

So let's assume things got fixed in 2.5.0 or a newer MSVC version? I don't think it's worth it to go retracing what actually went wrong and we're cleaning up the issues, so I'm closing this. But please reopen if this is still an issue!

[LeslieGerman]

Thanks for checking this @YannickJadoul !

I tested it with 2.5.0, but unfortunately the same error occurs in C++17 mode. Still works in C++14.
I tried python 3.6 and 3.8, but no difference.

I see from your log you used Visual Studio 2019, MSVC MSVC 19.25, so looks like the compiler is the difference.

The compiler I used: MSVC 19.16, is shipped with Visual Studio 2017, which is still the "main-line" for a lot of people.

I personally could overcome this problem, so for me it's OK to close the ticket. However I would consider trying to fix this, since VS 2017 is still widely used. It's up to you.

[bstaletic]

Let's reopen this, but it might take some time before we can have a good look at this.

[YannickJadoul]

Alright. Thanks for telling us! I'll see if I can find a VS 2017 installation, and I'll try again! :-)

[YannickJadoul]

@LeslieGerman Still can't reproduce with VS 2017 (MSVC 19.16.27041.0). Both with 32-bit and Python 3.7, as well as with 64-bit and Python 3.8 (these just happen to be the Python architecture versions I have installed on the Windows machine):

PS C:\Users\Yannick\pybind11\build> cmake .. -DPYBIND11_CPP_STANDARD=/std:c++17 -G "Visual Studio 15 2017"
-- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.18363.
-- The CXX compiler identification is MSVC 19.16.27041.0
-- Check for working CXX compiler: E:/Program Files (x86)/Microsoft Visual Studio/2017/BuildTools/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x
86/cl.exe
-- Check for working CXX compiler: E:/Program Files (x86)/Microsoft Visual Studio/2017/BuildTools/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x
86/cl.exe -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found PythonInterp: C:/Program Files (x86)/Python37-32/python.exe (found version "3.7.3") 
-- Found PythonLibs: C:/Program Files (x86)/Python37-32/libs/python37.lib
-- Building tests WITHOUT Eigen
-- Could NOT find Boost (missing: Boost_INCLUDE_DIR) (Required is at least version "1.56")
-- Performing Test HAS_MSVC_GL_LTCG
-- Performing Test HAS_MSVC_GL_LTCG - Success
-- LTO enabled
-- Catch not detected. Interpreter tests will be skipped. Install Catch headers manually or use `cmake -DDOWNLOAD_CATCH=1` to fetch them 
automatically.
-- pybind11 v2.5.dev1
-- Configuring done
-- Generating done                                                                                                                       
-- Build files have been written to: C:/Users/Yannick/pybind11/build        
PS C:\Users\Yannick\pybind11\build> cmake --build . --target pytest                                                                      
Microsoft (R) Build Engine version 15.9.21+g9802d43bc3 for .NET Framework                                                                
Copyright (C) Microsoft Corporation. All rights reserved.                                                                                
                                                                                                                                         
  Checking Build System                                                                                                                  
  Building Custom Rule C:/Users/Yannick/pybind11/tests/CMakeLists.txt                                                                    
  cross_module_gil_utils.cpp                                                                                                             
     Creating library C:/Users/Yannick/pybind11/build/tests/Debug/cross_module_gil_utils.lib and object C:/Users/Yannick/pybind11/build/ 
  tests/Debug/cross_module_gil_utils.exp                                                                                                 
  cross_module_gil_utils.vcxproj -> C:\Users\Yannick\pybind11\tests\cross_module_gil_utils.cp37-win32.pyd                                
  Building Custom Rule C:/Users/Yannick/pybind11/tests/CMakeLists.txt                                                                    
  pybind11_cross_module_tests.cpp                                                                                                        
     Creating library C:/Users/Yannick/pybind11/build/tests/Debug/pybind11_cross_module_tests.lib and object C:/Users/Yannick/pybind11/b 
  uild/tests/Debug/pybind11_cross_module_tests.exp                                                                                       
  pybind11_cross_module_tests.vcxproj -> C:\Users\Yannick\pybind11\tests\pybind11_cross_module_tests.cp37-win32.pyd                      
  Building Custom Rule C:/Users/Yannick/pybind11/tests/CMakeLists.txt                                                                    
  pybind11_tests.cpp                                                                                                                     
  test_async.cpp                                                                                                                         
  test_buffers.cpp                                                                                                                       
  test_builtin_casters.cpp                                                                                                               
  test_call_policies.cpp                                                                                                                 
  test_callbacks.cpp                                                                                                                     
  test_chrono.cpp                                                                                                                        
  test_class.cpp                                                                                                                         
  test_constants_and_functions.cpp                                                                                                       
  test_copy_move.cpp                                                                                                                     
  test_custom_type_casters.cpp                                                                                                           
  test_docstring_options.cpp                                                                                                             
  test_enum.cpp                                                                                                                          
  test_eval.cpp                                                                                                                          
  test_exceptions.cpp                                                                                                                    
  test_factory_constructors.cpp                                                                                                          
  test_gil_scoped.cpp                                                                                                                    
  test_iostream.cpp                                                                                                                      
  test_kwargs_and_defaults.cpp                                                                                                           
  test_local_bindings.cpp                                                                                                                
  Generating Code...                                                                                                                     
  Compiling...                                                                                                                           
  test_methods_and_attributes.cpp                                                                                                        
  test_modules.cpp                                                                                                                       
  test_multiple_inheritance.cpp                                                                                                          
  test_numpy_array.cpp                                                                                                                   
  test_numpy_dtypes.cpp                                                                                                                  
  test_numpy_vectorize.cpp                                                                                                               
  test_opaque_types.cpp                                                                                                                  
  test_operator_overloading.cpp                                                                                                          
  test_pickling.cpp                                                                                                                      
  test_pytypes.cpp                                                                                                                       
  test_sequences_and_iterators.cpp                                                                                                       
  test_smart_ptr.cpp                                                                                                                     
  test_stl.cpp                                                                                                                           
  test_stl_binders.cpp                                                                                                                   
  test_tagbased_polymorphic.cpp                                                                                                          
  test_union.cpp                                                                                                                         
  test_virtual_functions.cpp                                                                                                             
  Generating Code...                                                                                                                     
     Creating library C:/Users/Yannick/pybind11/build/tests/Debug/pybind11_tests.lib and object C:/Users/Yannick/pybind11/build/tests/De 
  bug/pybind11_tests.exp                                                                                                                 
  pybind11_tests.vcxproj -> C:\Users\Yannick\pybind11\tests\pybind11_tests.cp37-win32.pyd                                                
  ------ pybind11_tests.cp37-win32.pyd file size: 11380736                                                                               
  ============================= test session starts =============================                                                        
  platform win32 -- Python 3.7.3, pytest-5.3.2, py-1.8.1, pluggy-0.13.1                                                                  
  rootdir: C:\Users\Yannick\pybind11\tests, inifile: pytest.ini                                                                          
  plugins: lazy-fixture-0.6.2                                                                                                            
  collected 344 items
[...]
  ======================= 314 passed, 30 skipped in 7.93s =======================                                                        
  Building Custom Rule C:/Users/Yannick/pybind11/tests/CMakeLists.txt        

Can you reproduce, and give more details about the error (i.e., not just the 6 lines from your original post, but the full log, including where the occur, and what else the compiler says about it) ?

[LeslieGerman]

@YannickJadoul , huh, strange!

I re-tested it again, and here's the full log:

64 bit Windows, cmake and ninja used from VS 2017, pybind 2.5.0, python 3.6.10

(pybind11_test) D:\Libs\Pybind\2.5.0\build_ninja>where cmake
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe
(pybind11_test) D:\Libs\Pybind\2.5.0\build_ninja>where ninja
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja\ninja.exe

(pybind11_test) D:\Libs\Pybind\2.5.0\build_ninja>cmake --version
cmake version 3.12.18081601-MSVC_2

CMake suite maintained and supported by Kitware (kitware.com/cmake).
(pybind11_test) D:\Libs\Pybind\2.5.0\build_ninja>ninja --version
1.8.2

(pybind11_test) D:\Libs\Pybind\2.5.0\build_ninja>cls && cmake -G Ninja -DPYBIND11_CPP_STANDARD=/std:c++17 ..\src
-- The CXX compiler identification is MSVC 19.16.27038.0
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Professional/VC/Tools/MSVC/14.16.27023/bin/Hostx64/x64/cl.exe
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Professional/VC/Tools/MSVC/14.16.27023/bin/Hostx64/x64/cl.exe -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found PythonInterp: D:/Programs/Miniconda3/envs/pybind11_test/python.exe (found version "3.6.10")
-- Found PythonLibs: D:/Programs/Miniconda3/envs/pybind11_test/libs/Python36.lib
-- Building tests WITHOUT Eigen
-- Could NOT find Boost
-- Performing Test HAS_MSVC_GL_LTCG
-- Performing Test HAS_MSVC_GL_LTCG - Success
-- LTO enabled
-- Catch not detected. Interpreter tests will be skipped. Install Catch headers manually or use `cmake -DDOWNLOAD_CATCH=1` to fetch them automatically.
-- pybind11 v2.5.0
-- Configuring done
-- Generating done
-- Build files have been written to: D:/Libs/Pybind/2.5.0/build_ninja

(pybind11_test) D:\Libs\Pybind\2.5.0\build_ninja>cmake --build .
[1/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_async.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[2/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_chrono.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[3/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_call_policies.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[4/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_constants_and_functions.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[5/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\pybind11_tests.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[6/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_callbacks.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[7/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_buffers.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[8/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_builtin_casters.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[9/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_copy_move.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[10/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_class.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[11/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_exceptions.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[12/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_docstring_options.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[13/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_enum.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[14/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_eval.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[15/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_iostream.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[16/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_gil_scoped.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[17/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_local_bindings.cpp.obj
FAILED: tests/CMakeFiles/pybind11_tests.dir/test_local_bindings.cpp.obj
C:\PROGRA~2\MICROS~2\2017\PROFES~1\VC\Tools\MSVC\1416~1.270\bin\Hostx64\x64\cl.exe  /nologo /TP -Dpybind11_tests_EXPORTS -ID:\Libs\Pybind\2.5.0\src\include -ID:\Programs\Miniconda3\envs\pybind11_test\include /DWIN32 /D_WINDOWS /W3 /GR /EHsc /MDd /Zi /Ob0 /Od /RTC1   /std:c++17 /bigobj /W4 /utf-8 /showIncludes /Fotests\CMakeFiles\pybind11_tests.dir\test_local_bindings.cpp.obj /Fdtests\CMakeFiles\pybind11_tests.dir\ /FS -c D:\Libs\Pybind\2.5.0\src\tests\test_local_bindings.cpp
cl : Command line warning D9025 : overriding '/W3' with '/W4'
D:\Libs\Pybind\2.5.0\src\include\pybind11/stl_bind.h(434): error C2672: 'pybind11::detail::vector_buffer': no matching overloaded function found
D:\Libs\Pybind\2.5.0\src\tests\test_local_bindings.cpp(53): note: see reference to function template instantiation 'pybind11::class_<LocalVec,std::unique_ptr<Vector,std::default_delete<_Ty>>> pybind11::bind_vector<LocalVec,std::unique_ptr<_Ty,std::default_delete<_Ty>>,>(pybind11::handle,const std::string &)' being compiled
        with
        [
            Vector=LocalVec,
            _Ty=LocalVec
        ]
d:\libs\pybind\2.5.0\src\tests\pybind11_tests.h(60): note: see reference to class template instantiation 'pybind11::detail::descr<12>' being compiled
d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1602): note: see reference to class template instantiation 'pybind11::detail::descr<8>' being compiled
d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1600): note: see reference to class template instantiation 'pybind11::detail::descr<5>' being compiled
d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1145): note: see reference to class template instantiation 'pybind11::detail::descr<7>' being compiled
D:\Libs\Pybind\2.5.0\src\include\pybind11/stl_bind.h(422): error C2893: Failed to specialize function template 'enable_if<_Test,_Ty>::type pybind11::detail::vector_buffer(Class_ &)'
        with
        [
            _Ty=void
        ]
D:\Libs\Pybind\2.5.0\src\include\pybind11/stl_bind.h(422): note: With the following template arguments:
D:\Libs\Pybind\2.5.0\src\include\pybind11/stl_bind.h(422): note: 'Vector=Vector'
D:\Libs\Pybind\2.5.0\src\include\pybind11/stl_bind.h(422): note: 'Class_=Class_'
D:\Libs\Pybind\2.5.0\src\include\pybind11/stl_bind.h(422): note: 'Args={}'
[18/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_kwargs_and_defaults.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[19/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_modules.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[20/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_factory_constructors.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[21/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_numpy_vectorize.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[22/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_numpy_dtypes.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[23/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_multiple_inheritance.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[24/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_methods_and_attributes.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[25/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_numpy_array.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
[26/41] Building CXX object tests\CMakeFiles\pybind11_tests.dir\test_sequences_and_iterators.cpp.obj
cl : Command line warning D9025 : overriding '/W3' with '/W4'
ninja: build stopped: subcommand failed.

Exactly the same error with python 3.6.10, 3.7.6, 3.8.3.

[LeslieGerman]

I tried with "Visual Studio 15 2017 Win64" generator, too, but it produced the same error:

64 bit Windows, pybind 2.5.0, python 3.6.10

(pybind11_test) D:\Libs\Pybind\2.5.0\build_ninja>cls && cmake -G "Visual Studio 15 2017 Win64" -DPYBIND11_CPP_STANDARD=/std:c++17 ..\src
-- Selecting Windows SDK version 10.0.17763.0 to target Windows 10.0.18363.
-- The CXX compiler identification is MSVC 19.16.27038.0
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Professional/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x64/cl.exe
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Professional/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x64/cl.exe -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found PythonInterp: D:/Programs/Miniconda3/envs/pybind11_test/python.exe (found version "3.6.10")
-- Found PythonLibs: D:/Programs/Miniconda3/envs/pybind11_test/libs/Python36.lib
-- Building tests WITHOUT Eigen
-- Could NOT find Boost
-- Performing Test HAS_MSVC_GL_LTCG
-- Performing Test HAS_MSVC_GL_LTCG - Success
-- LTO enabled
-- Catch not detected. Interpreter tests will be skipped. Install Catch headers manually or use `cmake -DDOWNLOAD_CATCH=1` to fetch them automatically.
-- pybind11 v2.5.0
-- Configuring done
-- Generating done
-- Build files have been written to: D:/Libs/Pybind/2.5.0/build_ninja

(pybind11_test) D:\Libs\Pybind\2.5.0\build_ninja>cmake --build .
Microsoft (R) Build Engine version 15.9.21+g9802d43bc3 for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.

Build started 7/10/2020 6:27:16 PM.
Project "D:\Libs\Pybind\2.5.0\build_ninja\ALL_BUILD.vcxproj" on node 1 (default targets).
Project "D:\Libs\Pybind\2.5.0\build_ninja\ALL_BUILD.vcxproj" (1) is building "D:\Libs\Pybind\2.5.0\build_ninja\ZERO_CHE
CK.vcxproj" (2) on node 1 (default targets).
PrepareForBuild:
  Creating directory "x64\Debug\ZERO_CHECK\".
  Creating directory "x64\Debug\ZERO_CHECK\ZERO_CHECK.tlog\".
InitializeBuildStatus:
  Creating "x64\Debug\ZERO_CHECK\ZERO_CHECK.tlog\unsuccessfulbuild" because "AlwaysCreate" was specified.
CustomBuild:
  Checking Build System
  CMake does not need to re-run because D:/Libs/Pybind/2.5.0/build_ninja/CMakeFiles/generate.stamp is up-to-date.
  CMake does not need to re-run because D:/Libs/Pybind/2.5.0/build_ninja/tests/CMakeFiles/generate.stamp is up-to-date.
  CMake does not need to re-run because D:/Libs/Pybind/2.5.0/build_ninja/tests/test_embed/CMakeFiles/generate.stamp is
  up-to-date.
  CMake does not need to re-run because D:/Libs/Pybind/2.5.0/build_ninja/tests/test_cmake_build/CMakeFiles/generate.sta
  mp is up-to-date.
FinalizeBuildStatus:
  Deleting file "x64\Debug\ZERO_CHECK\ZERO_CHECK.tlog\unsuccessfulbuild".
  Touching "x64\Debug\ZERO_CHECK\ZERO_CHECK.tlog\ZERO_CHECK.lastbuildstate".
Done Building Project "D:\Libs\Pybind\2.5.0\build_ninja\ZERO_CHECK.vcxproj" (default targets).

Project "D:\Libs\Pybind\2.5.0\build_ninja\ALL_BUILD.vcxproj" (1) is building "D:\Libs\Pybind\2.5.0\build_ninja\tests\cr
oss_module_gil_utils.vcxproj" (3) on node 1 (default targets).
PrepareForBuild:
  Creating directory "cross_module_gil_utils.dir\Debug\".
  Creating directory "cross_module_gil_utils.dir\Debug\cross_mo.6D4D950E.tlog\".
InitializeBuildStatus:
  Creating "cross_module_gil_utils.dir\Debug\cross_mo.6D4D950E.tlog\unsuccessfulbuild" because "AlwaysCreate" was speci
  fied.
CustomBuild:
  Building Custom Rule D:/Libs/Pybind/2.5.0/src/tests/CMakeLists.txt
  CMake does not need to re-run because D:/Libs/Pybind/2.5.0/build_ninja/tests/CMakeFiles/generate.stamp is up-to-date.
ClCompile:
  D:\Tools\BullseyeCoverage\bin\CL.exe /c /ID:\Libs\Pybind\2.5.0\src\include /ID:\Programs\Miniconda3\envs\pybind11_tes
  t\include /I"C:\Programs\Visual Leak Detector\include" /Zi /nologo /W4 /WX- /diagnostics:classic /Od /Ob0 /D WIN32 /D
   _WINDOWS /D "CMAKE_INTDIR=\"Debug\"" /D cross_module_gil_utils_EXPORTS /D _WINDLL /D _MBCS /Gm- /EHsc /RTC1 /MDd /GS
   /fp:precise /Zc:wchar_t /Zc:forScope /Zc:inline /GR /std:c++17 /Fo"cross_module_gil_utils.dir\Debug\\" /Fd"cross_mod
  ule_gil_utils.dir\Debug\vc141.pdb" /Gd /TP /FC /errorReport:queue  /bigobj /utf-8 D:\Libs\Pybind\2.5.0\src\tests\cros
  s_module_gil_utils.cpp
  cross_module_gil_utils.cpp
MakeDirsForLink:
  Creating directory "D:\Libs\Pybind\2.5.0\build_ninja\tests\Debug\".
Link:
  D:\Tools\BullseyeCoverage\bin\link.exe /ERRORREPORT:QUEUE /OUT:"D:\Libs\Pybind\2.5.0\src\tests\cross_module_gil_utils
  .cp36-win_amd64.pyd" /INCREMENTAL /NOLOGO /LIBPATH:"C:\Programs\Visual Leak Detector\lib\Win64" D:\Programs\Miniconda
  3\envs\pybind11_test\libs\Python36.lib kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.
  lib uuid.lib comdlg32.lib advapi32.lib /MANIFEST /MANIFESTUAC:"level='asInvoker' uiAccess='false'" /manifest:embed /D
  EBUG /PDB:"D:/Libs/Pybind/2.5.0/src/tests/cross_module_gil_utils.pdb" /SUBSYSTEM:CONSOLE /TLBID:1 /DYNAMICBASE /NXCOM
  PAT /IMPLIB:"D:/Libs/Pybind/2.5.0/build_ninja/tests/Debug/cross_module_gil_utils.lib" /MACHINE:X64  /machine:x64 /DLL
   cross_module_gil_utils.dir\Debug\cross_module_gil_utils.obj
     Creating library D:/Libs/Pybind/2.5.0/build_ninja/tests/Debug/cross_module_gil_utils.lib and object D:/Libs/Pybind
  /2.5.0/build_ninja/tests/Debug/cross_module_gil_utils.exp
  cross_module_gil_utils.vcxproj -> D:\Libs\Pybind\2.5.0\src\tests\cross_module_gil_utils.cp36-win_amd64.pyd
FinalizeBuildStatus:
  Deleting file "cross_module_gil_utils.dir\Debug\cross_mo.6D4D950E.tlog\unsuccessfulbuild".
  Touching "cross_module_gil_utils.dir\Debug\cross_mo.6D4D950E.tlog\cross_module_gil_utils.lastbuildstate".
Done Building Project "D:\Libs\Pybind\2.5.0\build_ninja\tests\cross_module_gil_utils.vcxproj" (default targets).

Project "D:\Libs\Pybind\2.5.0\build_ninja\ALL_BUILD.vcxproj" (1) is building "D:\Libs\Pybind\2.5.0\build_ninja\tests\py
bind11_cross_module_tests.vcxproj" (4) on node 1 (default targets).
PrepareForBuild:
  Creating directory "pybind11_cross_module_tests.dir\Debug\".
  Creating directory "pybind11_cross_module_tests.dir\Debug\pybind11.5499A21F.tlog\".
InitializeBuildStatus:
  Creating "pybind11_cross_module_tests.dir\Debug\pybind11.5499A21F.tlog\unsuccessfulbuild" because "AlwaysCreate" was
  specified.
CustomBuild:
  Building Custom Rule D:/Libs/Pybind/2.5.0/src/tests/CMakeLists.txt
  CMake does not need to re-run because D:/Libs/Pybind/2.5.0/build_ninja/tests/CMakeFiles/generate.stamp is up-to-date.
ClCompile:
  D:\Tools\BullseyeCoverage\bin\CL.exe /c /ID:\Libs\Pybind\2.5.0\src\include /ID:\Programs\Miniconda3\envs\pybind11_tes
  t\include /I"C:\Programs\Visual Leak Detector\include" /Zi /nologo /W4 /WX- /diagnostics:classic /Od /Ob0 /D WIN32 /D
   _WINDOWS /D "CMAKE_INTDIR=\"Debug\"" /D pybind11_cross_module_tests_EXPORTS /D _WINDLL /D _MBCS /Gm- /EHsc /RTC1 /MD
  d /GS /fp:precise /Zc:wchar_t /Zc:forScope /Zc:inline /GR /std:c++17 /Fo"pybind11_cross_module_tests.dir\Debug\\" /Fd
  "pybind11_cross_module_tests.dir\Debug\vc141.pdb" /Gd /TP /FC /errorReport:queue  /bigobj /utf-8 D:\Libs\Pybind\2.5.0
  \src\tests\pybind11_cross_module_tests.cpp
  pybind11_cross_module_tests.cpp
d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(434): error C2672: 'pybind11::detail::vector_buffer': no matching
overloaded function found [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_cross_module_tests.vcxproj]
  d:\libs\pybind\2.5.0\src\tests\pybind11_cross_module_tests.cpp(52): note: see reference to function template instanti
  ation 'pybind11::class_<LocalVec,std::unique_ptr<Vector,std::default_delete<_Ty>>> pybind11::bind_vector<LocalVec,std
  ::unique_ptr<_Ty,std::default_delete<_Ty>>,>(pybind11::handle,const std::string &)' being compiled
          with
          [
              Vector=LocalVec,
              _Ty=LocalVec
          ]
  d:\libs\pybind\2.5.0\src\tests\pybind11_tests.h(60): note: see reference to class template instantiation 'pybind11::d
  etail::descr<12>' being compiled
  d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1602): note: see reference to class template instantiation 'pybind11
  ::detail::descr<8>' being compiled
  d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1600): note: see reference to class template instantiation 'pybind11
  ::detail::descr<5>' being compiled
  d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1145): note: see reference to class template instantiation 'pybind11
  ::detail::descr<7>' being compiled
d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): error C2893: Failed to specialize function template 'enable_
if<_Test,_Ty>::type pybind11::detail::vector_buffer(Class_ &)' [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_cross_m
odule_tests.vcxproj]
          with
          [
              _Ty=void
          ]
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: With the following template arguments:
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: 'Vector=Vector'
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: 'Class_=Class_'
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: 'Args={}'
Done Building Project "D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_cross_module_tests.vcxproj" (default targets) --
 FAILED.

Project "D:\Libs\Pybind\2.5.0\build_ninja\ALL_BUILD.vcxproj" (1) is building "D:\Libs\Pybind\2.5.0\build_ninja\tests\py
bind11_tests.vcxproj" (5) on node 1 (default targets).
PrepareForBuild:
  Creating directory "pybind11_tests.dir\Debug\".
  Creating directory "pybind11_tests.dir\Debug\pybind11_tests.tlog\".
InitializeBuildStatus:
  Creating "pybind11_tests.dir\Debug\pybind11_tests.tlog\unsuccessfulbuild" because "AlwaysCreate" was specified.
CustomBuild:
  Building Custom Rule D:/Libs/Pybind/2.5.0/src/tests/CMakeLists.txt
  CMake does not need to re-run because D:/Libs/Pybind/2.5.0/build_ninja/tests/CMakeFiles/generate.stamp is up-to-date.
ClCompile:
  D:\Tools\BullseyeCoverage\bin\CL.exe /c /ID:\Libs\Pybind\2.5.0\src\include /ID:\Programs\Miniconda3\envs\pybind11_tes
  t\include /I"C:\Programs\Visual Leak Detector\include" /Zi /nologo /W4 /WX- /diagnostics:classic /Od /Ob0 /D WIN32 /D
   _WINDOWS /D "CMAKE_INTDIR=\"Debug\"" /D pybind11_tests_EXPORTS /D _WINDLL /D _MBCS /Gm- /EHsc /RTC1 /MDd /GS /fp:pre
  cise /Zc:wchar_t /Zc:forScope /Zc:inline /GR /std:c++17 /Fo"pybind11_tests.dir\Debug\\" /Fd"pybind11_tests.dir\Debug\
  vc141.pdb" /Gd /TP /FC /errorReport:queue  /bigobj /utf-8 D:\Libs\Pybind\2.5.0\src\tests\pybind11_tests.cpp D:\Libs\P
  ybind\2.5.0\src\tests\test_async.cpp D:\Libs\Pybind\2.5.0\src\tests\test_buffers.cpp D:\Libs\Pybind\2.5.0\src\tests\t
  est_builtin_casters.cpp D:\Libs\Pybind\2.5.0\src\tests\test_call_policies.cpp D:\Libs\Pybind\2.5.0\src\tests\test_cal
  lbacks.cpp D:\Libs\Pybind\2.5.0\src\tests\test_chrono.cpp D:\Libs\Pybind\2.5.0\src\tests\test_class.cpp D:\Libs\Pybin
  d\2.5.0\src\tests\test_constants_and_functions.cpp D:\Libs\Pybind\2.5.0\src\tests\test_copy_move.cpp D:\Libs\Pybind\2
  .5.0\src\tests\test_docstring_options.cpp D:\Libs\Pybind\2.5.0\src\tests\test_enum.cpp D:\Libs\Pybind\2.5.0\src\tests
  \test_eval.cpp D:\Libs\Pybind\2.5.0\src\tests\test_exceptions.cpp D:\Libs\Pybind\2.5.0\src\tests\test_factory_constru
  ctors.cpp D:\Libs\Pybind\2.5.0\src\tests\test_gil_scoped.cpp D:\Libs\Pybind\2.5.0\src\tests\test_iostream.cpp D:\Libs
  \Pybind\2.5.0\src\tests\test_kwargs_and_defaults.cpp D:\Libs\Pybind\2.5.0\src\tests\test_local_bindings.cpp D:\Libs\P
  ybind\2.5.0\src\tests\test_methods_and_attributes.cpp D:\Libs\Pybind\2.5.0\src\tests\test_modules.cpp D:\Libs\Pybind\
  2.5.0\src\tests\test_multiple_inheritance.cpp D:\Libs\Pybind\2.5.0\src\tests\test_numpy_array.cpp D:\Libs\Pybind\2.5.
  0\src\tests\test_numpy_dtypes.cpp D:\Libs\Pybind\2.5.0\src\tests\test_numpy_vectorize.cpp D:\Libs\Pybind\2.5.0\src\te
  sts\test_opaque_types.cpp D:\Libs\Pybind\2.5.0\src\tests\test_operator_overloading.cpp D:\Libs\Pybind\2.5.0\src\tests
  \test_pickling.cpp D:\Libs\Pybind\2.5.0\src\tests\test_pytypes.cpp D:\Libs\Pybind\2.5.0\src\tests\test_sequences_and_
  iterators.cpp D:\Libs\Pybind\2.5.0\src\tests\test_smart_ptr.cpp D:\Libs\Pybind\2.5.0\src\tests\test_stl.cpp D:\Libs\P
  ybind\2.5.0\src\tests\test_stl_binders.cpp D:\Libs\Pybind\2.5.0\src\tests\test_tagbased_polymorphic.cpp D:\Libs\Pybin
  d\2.5.0\src\tests\test_union.cpp D:\Libs\Pybind\2.5.0\src\tests\test_virtual_functions.cpp
  pybind11_tests.cpp
  test_async.cpp
  test_buffers.cpp
  test_builtin_casters.cpp
  test_call_policies.cpp
  test_callbacks.cpp
  test_chrono.cpp
  test_class.cpp
  test_constants_and_functions.cpp
  test_copy_move.cpp
  test_docstring_options.cpp
  test_enum.cpp
  test_eval.cpp
  test_exceptions.cpp
  test_factory_constructors.cpp
  test_gil_scoped.cpp
  test_iostream.cpp
  test_kwargs_and_defaults.cpp
  test_local_bindings.cpp
d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(434): error C2672: 'pybind11::detail::vector_buffer': no matching
overloaded function found [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_tests.vcxproj]
  d:\libs\pybind\2.5.0\src\tests\test_local_bindings.cpp(53): note: see reference to function template instantiation 'p
  ybind11::class_<LocalVec,std::unique_ptr<Vector,std::default_delete<_Ty>>> pybind11::bind_vector<LocalVec,std::unique
  _ptr<_Ty,std::default_delete<_Ty>>,>(pybind11::handle,const std::string &)' being compiled
          with
          [
              Vector=LocalVec,
              _Ty=LocalVec
          ]
  d:\libs\pybind\2.5.0\src\tests\pybind11_tests.h(60): note: see reference to class template instantiation 'pybind11::d
  etail::descr<12>' being compiled
  d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1602): note: see reference to class template instantiation 'pybind11
  ::detail::descr<8>' being compiled
  d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1600): note: see reference to class template instantiation 'pybind11
  ::detail::descr<5>' being compiled
  d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1145): note: see reference to class template instantiation 'pybind11
  ::detail::descr<7>' being compiled
d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): error C2893: Failed to specialize function template 'enable_
if<_Test,_Ty>::type pybind11::detail::vector_buffer(Class_ &)' [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_tests.v
cxproj]
          with
          [
              _Ty=void
          ]
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: With the following template arguments:
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: 'Vector=Vector'
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: 'Class_=Class_'
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: 'Args={}'
  test_methods_and_attributes.cpp
  Generating Code...
  Compiling...
  test_modules.cpp
  test_multiple_inheritance.cpp
  test_numpy_array.cpp
  test_numpy_dtypes.cpp
  test_numpy_vectorize.cpp
  test_opaque_types.cpp
  test_operator_overloading.cpp
  test_pickling.cpp
  test_pytypes.cpp
  test_sequences_and_iterators.cpp
  test_smart_ptr.cpp
  test_stl.cpp
  test_stl_binders.cpp
d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(434): error C2672: 'pybind11::detail::vector_buffer': no matching
overloaded function found [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_tests.vcxproj]
  d:\libs\pybind\2.5.0\src\tests\test_stl_binders.cpp(72): note: see reference to function template instantiation 'pybi
  nd11::class_<std::vector<El,std::allocator<_Ty>>,std::unique_ptr<Vector,std::default_delete<std::vector<_Ty,std::allo
  cator<_Ty>>>>> pybind11::bind_vector<std::vector<_Ty,std::allocator<_Ty>>,std::unique_ptr<Vector,std::default_delete<
  std::vector<_Ty,std::allocator<_Ty>>>>,>(pybind11::handle,const std::string &)' being compiled
          with
          [
              _Ty=El,
              Vector=std::vector<El,std::allocator<El>>
          ]
  d:\libs\pybind\2.5.0\src\tests\pybind11_tests.h(60): note: see reference to class template instantiation 'pybind11::d
  etail::descr<12>' being compiled
  d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1602): note: see reference to class template instantiation 'pybind11
  ::detail::descr<8>' being compiled
  d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1600): note: see reference to class template instantiation 'pybind11
  ::detail::descr<5>' being compiled
  d:\libs\pybind\2.5.0\src\include\pybind11\cast.h(1145): note: see reference to class template instantiation 'pybind11
  ::detail::descr<7>' being compiled
d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): error C2893: Failed to specialize function template 'enable_
if<_Test,_Ty>::type pybind11::detail::vector_buffer(Class_ &)' [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_tests.v
cxproj]
          with
          [
              _Ty=void
          ]
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: With the following template arguments:
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: 'Vector=Vector'
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: 'Class_=Class_'
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): note: 'Args={}'
  test_tagbased_polymorphic.cpp
  test_union.cpp
  test_virtual_functions.cpp
  Generating Code...
Done Building Project "D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_tests.vcxproj" (default targets) -- FAILED.

Done Building Project "D:\Libs\Pybind\2.5.0\build_ninja\ALL_BUILD.vcxproj" (default targets) -- FAILED.


Build FAILED.

"D:\Libs\Pybind\2.5.0\build_ninja\ALL_BUILD.vcxproj" (default target) (1) ->
"D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_cross_module_tests.vcxproj" (default target) (4) ->
(ClCompile target) ->
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(434): error C2672: 'pybind11::detail::vector_buffer': no matchin
g overloaded function found [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_cross_module_tests.vcxproj]
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): error C2893: Failed to specialize function template 'enabl
e_if<_Test,_Ty>::type pybind11::detail::vector_buffer(Class_ &)' [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_cross
_module_tests.vcxproj]


"D:\Libs\Pybind\2.5.0\build_ninja\ALL_BUILD.vcxproj" (default target) (1) ->
"D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_tests.vcxproj" (default target) (5) ->
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(434): error C2672: 'pybind11::detail::vector_buffer': no matchin
g overloaded function found [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_tests.vcxproj]
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): error C2893: Failed to specialize function template 'enabl
e_if<_Test,_Ty>::type pybind11::detail::vector_buffer(Class_ &)' [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_tests
.vcxproj]
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(434): error C2672: 'pybind11::detail::vector_buffer': no matchin
g overloaded function found [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_tests.vcxproj]
  d:\libs\pybind\2.5.0\src\include\pybind11\stl_bind.h(422): error C2893: Failed to specialize function template 'enabl
e_if<_Test,_Ty>::type pybind11::detail::vector_buffer(Class_ &)' [D:\Libs\Pybind\2.5.0\build_ninja\tests\pybind11_tests
.vcxproj]

    0 Warning(s)
    6 Error(s)

Time Elapsed 00:02:27.87

I did NOT try with 32 bit compiler and 32 bit python...

[YannickJadoul]

Thanks! :-) Let's see if the full errors make sense, now!
So one difference is ninja vs. just MSBuild? But it would be weird if that's the issue.

I did NOT try with 32 bit compiler and 32 bit python...

Don't, it's fine like this. Both worked for me.

[YannickJadoul]

Oh, something else. Have you tried updating VS? It's probably not going to be that, but ...

[bstaletic]

I think I've seen this before. If I recall correctly, a workaround is adding an empty docstring.

Try something like this: py::bind_vector<SomeType(scope, "SomeType", "");.

[YannickJadoul]

I think I've seen this before. If I recall correctly, a workaround is adding an empty docstring.

Try something like this: py::bind_vector<SomeType(scope, "SomeType", "");.

But it's in pybind11's own tests? So if I can't reproduce, there's a difference between @LeslieGerman's MSVC 19.16.27038.0 and my MSVC 19.16.27041.0?

If I recall correctly, a workaround is adding an empty docstring.

Or ditching a broken compiler and an environment/OS that demonstrates again and again it's really not made for development? ;-)

[YannickJadoul]

Hooooooold your horses. Running that build again with VERBOSE=1 somehow shows I'm still compiling with C++14, rather than 17, even though I specified -DPYBIND11_CPP_STANDARD=/std:c++17. You're not telling me that's some kind of weird powershell, thing, right? I thought I finally had a shell on Windows with ls and dir and sane (sane'ish) rules about quoting etc??

[YannickJadoul]

OK. Reproduced. So some weird compiler thing we'll have to make a workaround for?

Thanks for holding on, @LeslieGerman!

EDIT: I reproduced by putting PYBIND11_CPP_STANDARD="/std:c++17"