Modifying clang-format to expose individual messages with distinct patches is the best way forward here.

Yeah, I checked before writing that last post, and I thought the same thing, but it's not split up the way we want. e.g.

I think the piece of information that differs between your model and the actual behavior of arc is that the linter does not (and must not) emit three separate corrections to fix foo(a, b, ...) one line at a time. It should emit a single correction for the entire block.

I haven't tried to write this rule, and you've almost convinced me to try, but -- forgive me -- I don't quite believe it's possible to do this correctly (or, as correctly as clang-format) in the context of formatting C++.

Thank you for your quick response.