Update the spec for the generated __info__/1 function to please Dialyzer

Verify the spec's correctness with `mix dialyze --specdiffs` in a dummy mix project.

Author: alco

lib/elixir/src/elixir_module.erl

@@ -431,18 +431,28 @@ add_info_function(Line, File, Module, All, Def, Defmacro) ->
  true ->
  elixir_errors:form_error([{line, Line}], File, ?MODULE, {internal_function_overridden, Pair});
  false ->
+ AllowedArgs =
+ lists:map(fun(Atom) -> {atom, Line, Atom} end,
+ [attributes, compile, exports, functions, macros, md5, module, native_addresses]),
  Spec =
  {attribute, Line, spec, {Pair,
  [{type, Line, 'fun', [
  {type, Line, product, [
- {type, Line, atom, []}
+ {type, Line, union, AllowedArgs}
  ]},
  {type, Line, union, [
  {type, Line, atom, []},
  {type, Line, list, [
- {type, Line, tuple, [
- {type, Line, atom, []},
- {type, Line, any, []}
+ {type, Line, union, [
+ {type, Line, tuple, [
+ {type, Line, atom, []},
+ {type, Line, any, []}
+ ]},
+ {type, Line, tuple, [
+ {type, Line, atom, []},
+ {type, Line, byte, []},
+ {type, Line, integer, []}
+ ]}
  ]}
  ]}
  ]}