anchor.diff:      nil;
   parse_type({type, _Line, node, []}, _Module) ->
       node;
  +parse_type({type, _Line, none, []}, _Module) ->
  +    none;
   parse_type({type, _Line, reference, []}, _Module) ->
       reference;
   parse_type({type, _Line, term, []}, _Module) ->
  
positive.code:     | pid
      | port
      | reference
      | {typedef, module(), atom()}
      | atom
      | float
  
negative.code:     UnknownTypes;
  find_unknown_types_helper(reference, _TypeInfo, UnknownTypes) ->
      UnknownTypes;
  find_unknown_types_helper(none, _TypeInfo, UnknownTypes) ->
      UnknownTypes;
  find_unknown_types_helper(nil, _TypeInfo, UnknownTypes) ->
      UnknownTypes;
  find_unknown_types_helper(node, _TypeInfo, UnknownTypes) ->
  