Compile error

[TrailingDots]

I added the routines on the README page to the exnn code.

Now I have:

exnn/lib
exnn/lib/exnn        # <- exnn base code
exnn/lib/myapp     # <- Routines from README code

I run as:

mix test test/examples/xor_test.exs
    ...
== Compilation error in file lib/my_app/fitness.ex ==
** (ArgumentError) struct fields definition must be list, got: %{inner_temp: 0.0, outer_temp: 40.0}
    (elixir) lib/kernel/utils.ex:73: Kernel.Utils.defstruct/2
    lib/my_app/fitness.ex:2: (module)
    (stdlib) erl_eval.erl:670: :erl_eval.do_apply/6

Struct fields are not a list. Is this a poor compiler error message? Does the compiler
have a problem?

The first few lines of lib/my_app/fitness.ex:

defmodule MyApp.Fitness do
  use EXNN.Fitness, state: %{inner_temp: 0.0, outer_temp: 40.0}

My configuration:

iex
Erlang/OTP 20 [erts-9.3] [source] [64-bit] [smp:12:12] [ds:12:12:10] [async-threads:10] [hipe] [kernel-poll:false]

Interactive Elixir (1.6.6) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> 
^c^c

erl
Erlang/OTP 20 [erts-9.3] [source] [64-bit] [smp:12:12] [ds:12:12:10] [async-threads:10] [hipe] [kernel-poll:false]

Eshell V9.3  (abort with ^G)
1> 

I'm assuming this is a version skew problem?