diagnostics over to it.
There are a few differences between this diagnostic engine and Clang's
engine:
- Diagnostics are specified by a .def file (Diagnostics.def), rather
than via tblgen, which drastically simplifies the build and makes
code completion work when you add a new diagnostic.
- Calls to the "diagnose()" method are safely typed based on the
argument types specified in the .def file, so it's harder to write a
diagnostic whose expected arguments (in the string) and whose actual
arguments (in the code) don't match.
- It uses variadic templates, so it hangs with the cool kids.
Swift SVN r734
