Rust's newer scheme is basically the same way it works by convention in Elixir (a more modern language than Golang or the others you listed). The older mod.rs

Rust's newer scheme is basically the same way it works by convention in Elixir (a more modern language than Golang or the others you listed). The older mod.rs scheme seems like an unneeded special case to me, but even that isn't exactly alien compared to what other popular programming languages have done before.