credo_plus

defmodule Credo.Check.Warning.UnusedPathOperation do
  @moduledoc false

  @checkdoc """
  The result of a call to the Path module's functions has to be used.

  While this is correct ...

      def read_from_cwd(filename) do
        filename = Path.join(cwd, filename)

        File.read(filename)
      end

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

      def read_from_cwd(filename) do
        Path.join(cwd, filename)

        File.read(filename)
      end

  Path operations never work on the variable you pass in, but return a new
  variable which has to be used somehow.
  """
  @explanation [check: @checkdoc]
  @checked_module :Path
  @funs_with_return_value nil

  use Credo.Check, base_priority: :high

  alias Credo.Check.Warning.UnusedOperation

  def run(source_file, params \\ []) do
    UnusedOperation.run(
      source_file,
      params,
      @checked_module,
      @funs_with_return_value,
      &format_issue/2
    )
  end
end