While learning Elixir and Phoenix, I found Cowboy source code easier to read with no knowledge of Erlang other than what's inferred from learning Elixir than Phoenix's generated app scaffolding.

In Erlang, I look at 'module_name:function_name' I can simply open the module file and look at the function definition.

In Elixir, I had to ask "Was this function aliased?", "Is it imported from a module? Which module?", "Was it imported/aliased through a use statement?" The code was more concise, but harder to read IMO. Of course you can simply reference functions by their full name in Elixir as well, which is what I'm doing with my own code.