[Niall Douglas]
I've been using C2 clang as my daily Windows compiler for over a year now. Just for the improved warnings and diagnostics alone it is amazing. I know Microsoft say it's not production ready
Sorry, but we aren't planning to update Clang/C2 for C++. Clang/C2 3.8 in VS 2017 15.3 (first toolset update) will be the final version supported by our STL. We're now testing our STL with Clang/LLVM 4.0 which will be supported in the second toolset update - unless (depending on release timing) I increase the required version to Clang/LLVM 5.0.
The Clang/LLVM team has been doing amazing work to ensure source and binary compatibility; by "will be supported" I mean that on Microsoft's end, we're running Clang/LLVM in our test harness (against our own test suites, and libc++'s tests with our STL) to find obscure issues and prevent regressions as we change our code and take advantage of new features. For example, Clang/LLVM 4.0 lacked an atomic builtin; the workaround is to include