This absolutely should be a thing, but it'll have to be a per-community thing, them building their own dataset and creating their own evals (similar to how people do for production workloads).
Although:
"(idiomatic, etc.)" I don't think that should be part of the aim (or it should be under-weighted), because... you can just provide guidance on how to do things more idiomatically, rather than depend on that knowledge already being encoded in the model. I'd be more curious about verifying that it can work through gnarly bugs / features in an Elixir codebase. After all, what use is a model that by default does everything idiomatically if it can't figure out some small concurrency bug.
Although:
"(idiomatic, etc.)" I don't think that should be part of the aim (or it should be under-weighted), because... you can just provide guidance on how to do things more idiomatically, rather than depend on that knowledge already being encoded in the model. I'd be more curious about verifying that it can work through gnarly bugs / features in an Elixir codebase. After all, what use is a model that by default does everything idiomatically if it can't figure out some small concurrency bug.