I checked this, the logic is as follows. The following suffixes are mapped to the equivalent driver flags: {"clang", nullptr} {"clang++", "--driver-mod

I checked this, the logic is as follows. The following suffixes are mapped to the equivalent driver flags: {"clang", nullptr} {"clang++", "--driver-mode=g++"} {"clang-c++", "--driver-mode=g++"} {"clang-cc", nullptr} {"clang-cpp", "--driver-mode=cpp"} {"clang-g++", "--driver-mode=g++"} {"clang-gcc", nullptr} {"clang-cl", "--driver-mode=cl"} {"cc", nullptr} {"cpp", "--driver-mode=cpp"} {"cl", "--driver-mode=cl"} {"++", "--driver-mode=g++"} {"flang", "--driver-mode=flang"} `clang++-x` matches none of these. Then the same logic is applied to the name with any of "0123456789." trimmed from the right. Still no match. Then the trailing `-component` is stripped, and `clang++` matches. It works by chance... See https://github.com/llvm/llvm-project/blob/c22b110612600b0d0a8003f40b1cf6e37c4696c2/clang/lib/Driver/ToolChain.cpp#L135-L163 https://github.com/llvm/llvm-project/blob/c22b110612600b0d0a... and https://github.com/llvm/llvm-project/blob/c22b110612600b0d0a8003f40b1cf6e37c4696c2/clang/lib/Driver/ToolChain.cpp#L177-L201 https://github.com/llvm/llvm-project/blob/c22b110612600b0d0a... TIL: if you symlink ++ -> clang it works as a compiler in C++ mode.