this error, totally traceable:
1) test_syntax_code_error (Kernel.CLI.SyntaxErrorTest)
     ** (Protocol.UndefinedError) protocol Binary.Chars not implemented for [42, 42, 32, 40, 83, 121, 110, 116, 97, 120, 69, 114, 114, 111, 114, 41, 32, 110, 111, 102, 105, 108, 101, 58, 49, 58, 32, 105, 110, 118, 97, 108, 105, 100, 32, 116, 111, 107, 101, 110, 58, 32, 12354], only iolists are supported
     stacktrace:
       s:/workspace.elixir.2013/elixir/lib/elixir/lib/binary/chars.ex:65: Binary.Chars.List.to_binary/1
       elixir_windows_racing_trackdown_test.exs:58: Kernel.CLI.SyntaxErrorTest.test_syntax_code_error/1
ok it's not this
it was this! hmm