https://cppcast.com/cpp-builder/ - this is the podcast where embarcadero devs tell about how they maintain number of patches to llvm's compiler to make it compatible with necessary non-standard features like closures.
this also tells us that c++ became so big and complicated that one company (embarcadero size company) is not able anymore to support own compiler, they need to maintain own patches.
If you look at C++ standard support in major compilers, you'll find that no compiler on earth supports the whole C++20 standard. Gcc is the one that gets closest, but still has several "partially supported" features.
this also tells us that c++ became so big and complicated that one company (embarcadero size company) is not able anymore to support own compiler, they need to maintain own patches.