 end
 
 defmodule CompileError do
-  defexception [file: nil, line: nil, description: "compile error"]
+  defexception [:file, :line, description: "compile error"]
 
   def message(%{file: file, line: line, description: description}) do
     Exception.format_file_line(file && Path.relative_to_cwd(file), line) <>

end

defmodule BadArityError do
  defexception [function: nil, args: nil]

  def message(exception) do
    fun  = exception.function

end

defmodule MatchError do
  defexception [:term]

  def message(exception) do
    "no match of right hand side value: #{inspect(exception.term)}"
