I have predicates that rely on the @dev and @prod module attributes to know in which environment we’re in.

In config/dev.exs, I have the following configuration among other things:

config :myapp,
  dev:  true,
  prod: false

My @dev module attribute is defined like that:

@dev Application.compile_env!(:myapp, :dev)

When I write a predicate like:

cond do
  @dev && ... -> ...

Elixir warns me that this check/guard will always yield the same result which is true but I do not want to be warned because the produced code is ok even if the translation gives false && ... (because we’re in production). Is there a way to disable the warning or to refactor the usage? Is it considered bad style?

A priori without pattern matching on function arguments unless there is no other way.

The cond expression looks like:

cond do
  @dev && <dev condition>   -> <dev expression>
  @prod && <prod condition> -> <prod expression>
  <condition>               -> <expression>
  true                      -> <true expression>
end