[PATCH] D27679: Simplify format member detection in FormatVariadic

[Zachary Turner via Phabricator via llvm-commits]

zturner added a comment.

Can you confirm that after your changes, we still trigger the `missing_format_adapter` error message if you try to format a type that doesn't have a formatter?

For example, just make a dummy class `Foo` and try to pass an instance of it to `formatv`.  Make sure that the error message says something about `missing_format_adapter<T> where T = 'Foo'`.


https://reviews.llvm.org/D27679