How reloading can work?

[erlyvideo]

elixir_module is too strict for old modules:

check_module_available(ElixirName) ->
try
ErrorInfo = elixir_constants:lookup(ElixirName, attributes),
[{ErrorFile,ErrorLine}] = proplists:get_value(exfile, ErrorInfo),
error({module_defined, {ElixirName, list_to_binary(ErrorFile), ErrorLine}})
catch
error:{no_module, _} -> []
end.

Proper procedure is to call

Erlang.code.soft_purge('ex + ElixirName) and then overload module.