https://developercommunity.visualstudio.com/t/Frontend-crash-when-compiling-nested-tem/10612923
This repository reproduces a MSVC compiler crash in the frontend:
1>main.cpp
1>C:\Projects\MSVCBug\main.cpp(12,1): fatal error C1001: Internal compiler error.
1>(compiler file 'msc1.cpp', line 1587)
1> To work around this problem, try simplifying or changing the program near the locations listed above.
1>If possible please provide a repro here: https://developercommunity.visualstudio.com
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1>INTERNAL COMPILER ERROR in 'C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.39.33519\bin\HostX64\x64\CL.exe'
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1>Done building project "MSVCBug.vcxproj" -- FAILED.
You can also observe this in the GitHub CI: https://github.com/jdoubleu/MSVCBug/actions/runs/8224493505/job/22488396152#step:4:31
GCC and Clang are able to compile the code: https://godbolt.org/z/ajvj5jh68
This crash might be caused by the following properties, in combination:
- the 2nd level nested tempalted IIFE inside the fold expansion.
- usage of the
thispointer inside the nested lambdas.
If you change the this assignment, as commented, it doesn't crash. Likewise, if you remove the outer lambda, it doesn't crash neither.
The code doesn't compiler when you remove the template from .template operator()<.., which might be fine. The error messages aren't really helpful here. GCC hints, that you need to use template. Maybe this could be improved too.