Greetings fellow developers from the land of Microsoft,
With lots of changes making their way into the tree, I'm starting to look at some of the quality of implementation issues with the toolchain. One thing that is now starting to come up is the diagnostics in swift. This is actually something pretty common in the test suite as well.
The problem stems in the fact that the diagnostic engine in swift is slightly different from clang. It uses a SuS (Single Unix Specification) extension in the printf which allows you to render arguments using numbered references. Unfortunately, Microsoft's printf implementation does not support this functionality.
I am really stuck on how to best address this. Do we really want to provide an implementation of printf in the compiler for this functionality? Do we want to use portable C standard only functionality? Or is there some other approach that might be nicer to take?