crash_1.erl:45: Record construction #targetlist{list::[]} violates the declared type of field list::crash_1:target() crash_1.erl:48: The call crash_1:get_using_branch2(Branch::maybe_improper_list(),L::crash_1:target()) will never return since it differs in the 2nd argument from the success typing arguments: (any(),maybe_improper_list()) crash_1.erl:50: The pattern <_Branch, []> can never match the type crash_1.erl:52: The pattern can never match the type crash_1.erl:54: The pattern can never match the type