View Source Credo.Check.Warning.UnusedListOperation (Credo v1.7.5)

Basics

This check is enabled by default.

Learn how to disable it via .credo.exs.

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

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.

Check-Specific Parameters

There are no specific parameters for this check.

General Parameters

Like with all checks, general params can be applied.

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