Frontend crash (exit code 139) when compiling custom variant implementation

[jozef-plsko]

After moving a templated method implementation of my custom variant outside the class body, Clang 18.1.3 crashes during compilation with the following output:

clang++: error: clang frontend command failed with exit code 139 (use -v to see invocation)
Ubuntu clang version 18.1.3 (1ubuntu1)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
clang++: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang++: note: diagnostic msg: /tmp/mainSandbox-5ebe94.cpp
clang++: note: diagnostic msg: /tmp/mainSandbox-5ebe94.sh
clang++: note: diagnostic msg: 

********************
gmake[2]: *** [CMakeFiles/btlSandbox.dir/build.make:160: CMakeFiles/btlSandbox.dir/home/jozef/dev/cpp/current/betterTemplateLibrary/sandbox/source/mainSandbox.cpp.o] Error 1
gmake[2]: Leaving directory '/home/jozef/dev/cpp/current/betterTemplateLibrary/sandbox/build/artifacts/build_tests'
gmake[1]: *** [CMakeFiles/Makefile2:83: CMakeFiles/btlSandbox.dir/all] Error 2
gmake[1]: Leaving directory '/home/jozef/dev/cpp/current/betterTemplateLibrary/sandbox/build/artifacts/build_tests'
gmake: *** [Makefile:91: all] Error 2

The full crash dump and the preprocessed source/run script generated by Clang are attached exactly as emitted.

mainSandbox-5ebe94.cpp
mainSandbox-5ebe94.sh

[EugeneZelenko]

Could you please try 21 or main branch? Only most recent release is maintained.

[jozef-plsko]

I installed the latest Clang 21:

clang++-21 --version
Ubuntu clang version 21.1.6 (++20251113094015+a832a5222e48-1~exp1~20251113094129.62)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm-21/bin

With this version the code builds successfully without crashes or errors.
Just in case, I also run again the default apt Clang 18.1.3 and it is still crashing, so the issue appears to be fixed in latest version.