Export Used Types

Types used in typespecs for exported functions should also be exported.

Avoid

-module(mylib).

-export([myfun/1]).
-type mytype() :: term().

-spec myfun(mytype()) -> ok.
myfun(Var) ->
    ok = do_something_with(Var).

Prefer

Note the use of export_type in the example below.

-module(mylib).

-export([myfun/1]).
-type mytype() :: term().
-export_type([mytype/0]).

-spec myfun(mytype()) -> ok.
myfun(Var) ->
    ok = do_something_with(Var).

Rationale

Exporting a function without exporting the types it depends on can lead to redundant type definitions in each module that uses those functions. To prevent this, when a function is exported, its dependent types should also be exported.

Options

• None.

Example configuration

{elvis_style, export_used_types, #{}}