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veselink1 / refl-cpp

Static reflection for C++17 (compile-time enumeration, attributes, proxies, overloads, template functions, metaprogramming).
https://veselink1.github.io/refl-cpp/md__introduction.html
MIT License
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Visual Studio 2017 code formatter breaks compilation for refl.hpp #20

Closed ScottHutchinson closed 4 years ago

ScottHutchinson commented 4 years ago

Create a new C++ console application. Set warnings to level 4. Target latest. Build with the Visual Studio 2017 (v141) compiler:

Severity    Code    Description Line    File    Project Suppression State
Error   C2760   syntax error: unexpected token 'identifier', expected 'type specifier'  2563    ..\refltestconsole\refl.hpp ReflTestConsole 
Error   C2270   'MemberName_': modifiers not allowed on nonmember functions 2565    ..\refltestconsole\refl.hpp ReflTestConsole 
Error   C2995   'decltype(auto) MemberName_(Args &&...)': function template has already been defined    2568    ..\refltestconsole\refl.hpp ReflTestConsole 
Error   C2059   syntax error: '}'   2569    ..\refltestconsole\refl.hpp ReflTestConsole 
Error   C2143   syntax error: missing ';' before '}'    2569    ..\refltestconsole\refl.hpp ReflTestConsole 
Error   C2143   syntax error: missing ';' before '{'    2610    ..\refltestconsole\refl.hpp ReflTestConsole 
Error   C2447   '{': missing function header (old-style formal list?)   2610    ..\refltestconsole\refl.hpp ReflTestConsole 
Error   C2143   syntax error: missing ';' before 'namespace'    2771    ..\refltestconsole\refl.hpp ReflTestConsole 
Error   C1075   '{': no matching token found    2779    ..\refltestconsole\refl.hpp ReflTestConsole
veselink1 commented 4 years ago

Hi! It compiles without errors on the v142 (VS 2019) toolchain with language standard set to C++17. I will be testing on v141 soon.

veselink1 commented 4 years ago

I was able to compile and run all the examples successfully with Visual Studio 2019 with the VS 2017 Build Tools (v141) version 15.9.23, at /W4, with both -std=c++17 and -std=c++latest. I wasn't able to run the tests, however, as it seems that lambdas in a constexpr context are not fully supported in v141 (compiles fine with v142), but that is easily fixable.

Could this be a bug with an older version of the v141 toolchain? Would you mind sharing specific build tools version number and maybe some source code?

Also, is this on the lastest v0.9.1 release? I am unable to find some of the symbols mentioned in the error output at the specified line.

veselink1 commented 4 years ago

I can however see two things which might be the culprit. Trailing \ at refl.hpp:2798 Comment in macro at refl.hpp:2785

ScottHutchinson commented 4 years ago

It is happening with the latest version of Visual Studio 2017, which is 15.9.23. I also reproduced it in Visual Studio 2019, but with the 2017 compiler v141. You can get my source code at https://github.com/ScottHutchinson/ReflTestConsole

The rfl.hpp content is identical to the one in the master branch. I've never seen code with so many \ for line continuation, so maybe that is causing the problem.

From the build log:

       ClCompile:
         C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.16.27023\bin\HostX86\x86\CL.exe /c /ZI /JMC /nologo /W4 /WX- /diagnostics:classic /sdl /Od /Oy- /D WIN32 /D _DEBUG /D _CONSOLE /D _UNICODE /D UNICODE /Gm- /EHsc /RTC1 /MDd /GS /fp:precise /permissive- /Zc:wchar_t /Zc:forScope /Zc:inline /std:c++latest /Fo"Debug\\" /Fd"Debug\vc141.pdb" /Gd /TP /analyze- /FC /errorReport:prompt ReflTestConsole.cpp
ScottHutchinson commented 4 years ago

Retargeting to the v142 compiler does not help.

veselink1 commented 4 years ago

Strange. There seems to be something wierd happending with your refl.hpp file. v0.9.1 refl.hpp:2791 your refl.hpp:2559 The macro definition seems all broken up in your version. I am unable to reproduce running git clone on Windows or Linux, so it is curious as to what has caused this.

Replacing with the v0.9.1 source fixes the issue. Can you confirm that this fixes it for you as well?

ScottHutchinson commented 4 years ago

When I compare the file I tested with the one in master, they are binary same.

ScottHutchinson commented 4 years ago

The only difference I see between the two files you referenced above is that the opening { are on the their own line in the v0.9.1 file. My IDE is set to automatically format C++ files with the opening { on the same line with the function definition, etc. EDIT: Oh, I think the formatter is moving the \ too, which is probably what is breaking it.

ScottHutchinson commented 4 years ago

Yeah, that fixes it. I just manually moved about four \ to the previous line. Now it builds.

veselink1 commented 4 years ago

Glad you were able to resolve this! Seems to be related to the multiline comment in the macro at refl.hpp:2553, as the breaking changes made by the formatter are right after that. I will be moving that multiline comment out of the macro with the next release, so that should fix it for anyone using code formatters.