➜ cat my_test.hrl
-type my_enum() :: atom1 |
                   atom2 .
-spec check(my_enum()) -> boolean().
oleg@x200:~/dev
➜ cat my_test.erl
-module(my_test).
-include_lib("my_test.hrl").
-export([check/1, do_test/0]).

check(Data) ->
    io:format("data ~p~n", [Data]).

do_test() ->
    check(atom1),
    check(bad),
    check(atom2).
oleg@x200:~/dev
➜ erlc -d +debug_info -Wall my_test.erl
 erl +sbtu +A0 -noinput -mode minimal -boot start_clean -s erl_compile compile_cmdline -extra +debug_info -Wall my_test.erl
oleg@x200:~/dev
➜ dialyzer --build_plt my_test.beam
  Creating PLT /home/oleg/.dialyzer_plt ...
Unknown functions:
  erlang:get_module_info/1
  erlang:get_module_info/2
  io:format/2
 done in 0m0.34s
done (passed successfully)
oleg@x200:~/dev
➜ dialyzer --src my_test.erl
  Checking whether the PLT /home/oleg/.dialyzer_plt is up-to-date... yes
  Proceeding with analysis...
my_test.erl:8: Function do_test/0 has no local return
my_test.erl:10: The call my_test:check('bad') breaks the contract (my_enum()) -> boolean()
Unknown functions:
  erlang:get_module_info/1
  erlang:get_module_info/2
  io:format/2
 done in 0m0.24s
done (warnings were emitted)
➜ echo $?
2