Elixir will warn when variables prefixed with underscore are used

[eksperimental]

underscore_variable() ->
  case 1 of
    x when is_atom(x) ->
      atom;
    _Other ->
      _Other
  end.

will transpile as

  defp underscore_variable() do
    case (1) do
      :x when is_atom(:x) ->
        :atom
      _Other ->
        _Other
    end
  end

but the compiler will emit a warning:

warning: the underscored variable "_Other" is used after being set. A leading underscore indicates that the value of the variable should be ignored. If this is intended please rename the variable to remove the underscore
  out/samples/cornercases.ex:215: :cornercases.underscore_variable/0

I think the underscore should be removed

[marianoguerra]

The problem is that there may be a variable called Other, removing the underscore may change the meaning of the program.

[eksperimental]

A good compromise would be to remove the underscore if there is no other variable named like that. If there is, leave it and let the user deal with the warning. Having _Other and Other and using both is bad practice anyway.

[eksperimental]

I see what you mean. It is related to the other variable scope issue. It could use the name of another variable defined outside case, or the program relies on the variable after case.