I wrote a tool[0] that converts Erlang style Dialyzer messages to enough of Elixir to where the Elixir formatter can pretty print it. This isn't an intractable problem, but the source tool does really bizarre things so the output so it wound up being really annoying to deal with the quirks. Still not quite done, but it's in a workable state to where messages can be dealt with individually when the errors are poor.
Hey, I'm also working on something similar, namely automatic Elixir to Erlang code transformation at the AST level [0].
Despite it being really interesting, some features like scope analysis for variables detection and conversion, the possiblity of multiple modules in an Elixir file and the Elixir pipes which need to be translated to sequential function calls are honestly a pain in the ass.
[0] https://github.com/asummers/erlex [1] https://github.com/jeremyjh/dialyxir