'clang' is probably approaching the point that its good enough so the question for Microsoft is do they still see any value in continuing the develop their own compiler or should they just switch to 'clang' ?
I think this is the big shift we are seeing in MS this year. Instead trying to owning everything, they seem to be shifting their focus to owning the parts that have value and commoditizing the rest. The strategy was successful for Apple so its unsurprising that Microsoft is looking to a similar strategy as part of their salvation.
I know, I know, that's foolish, but it would be so great if that could be true ^^
If you mean C and C++ features, Microsoft standard conformance has slowly improved over the years from not giving a fuck to reasonable, but the only bleeding edge tools they've ever created are experimental research projects. They are completely out of clang and GCC's race to implement C and C++ standards and future standard changes.
If you mean some new API, they are libraries and all compilers have equal access to them.