I miss static typing for two separate and quite opposite cases:

* trivial errors, that still cause a crash and waste my time ("foo(:yo, 7)" but was "foo(7, :yo)") - sometimes spotted by Dyalizer

* complex nested structures. In Java I never have surprises as to what foo.bar.baz is and I can use autocomplete reliably. Expressing the same invariant in Elixir is something less straightforward

The fact that you _can_ open a REPL in production and inspect the data at runtime is huge.

Although few people use hotloading in code before, shapes of data can change from deployment to deployment.

> You'll always run into situations where the shape of data is not clear

If you're using typespecs, then I think the deficiency is with tooling. I think the language servers (like ElixirLS) were quite buggy for a while, but it's getting better at code completion and inspection. But if the type has no spec then you're in the same situation as any gradually typed language.

That’s okay. I’d rather do that once in a while to keep all of elixir’s dynamic traits. The fact that you can open a REPL, and open one in prod, do language introspection, inspect data, query DBs with ecto, do hot code swapping is amazing.

Until we have something like Set Theoretical Types, I think this is the best of both worlds.