anchor.diff:  default_release(M, Name, Vsn) ->
       M#state_t{default_release={Name, Vsn}}.
   
  --spec available_apps(t()) -> [app_descriptor()].
  +-spec available_apps(t()) -> [rcl_app_info:t()].
   available_apps(#state_t{available_apps=Apps}) ->
       Apps.
   
  --spec available_apps(t(), [app_descriptor()]) -> t().
  +-spec available_apps(t(), [rcl_app_info:t()]) -> t().
   available_apps(M, NewApps) ->
       M#state_t{available_apps=NewApps}.
   
  
positive.code: 
  
  -export_type([t/0,
                app_descriptor/0,
                releases/0,
                cmd_args/0]).
  
  
negative.code: %%============================================================================
  %% types
  %%============================================================================
  
  -type releases() :: ec_dictionary:dictionary({rcl_release:name(),
                                                rcl_release:vsn()},
  