View Source Credo.Check.Warning.UnusedListOperation (Credo v1.7.0)

This check has a base priority of high and works with any version of Elixir.

explanation
Explanation

The result of a call to the List module's functions has to be used.

While this is correct ...

def sort_usernames(usernames) do
  usernames = List.flatten(usernames)

  List.sort(usernames)
end

... we forgot to save the result in this example:

def sort_usernames(usernames) do
  List.flatten(usernames)

  List.sort(usernames)
end

List operations never work on the variable you pass in, but return a new variable which has to be used somehow.

There are no specific parameters for this check.

Like with all checks, general params can be applied.

Parameters can be configured via the .credo.exs config file.