This repo contains a number of examples intended to demonstrate how the Elixir compiler works, and how it figures out which files need to be recompiled.
mix deps.get
mix compile
In each of the numbered folders in lib you will find a few small Elixir files and a README. The README asks questions about what gets re-compiled when you make edits. To give it a try just edit one of the files and re-run the elixir compiler in verbose mode so you can see what is being recompiled.
mix compile --verbose