How do you get the elixir compiler to show warnings when running a phoenix server?

Question

Running a phoenix server in iex session via mix, like:

iex -S mix phx.server

Will sometimes give a list of warnings like:

Compiling 1 file (.ex)
warning: variable "user" is unused
  lib/app_web/controllers/user_controller.ex:37

But seemingly only the first time the server is run, after which I suppose its cached and so it doesn't show up. How can I at a later time see these warnings to fix them? Thanks.

Answer 1

Run mix compile --force to see all warnings again.

Answer 2

A simple method, use mix clean before iex -S mix phx.server, which will clean cache and show up warnings again.