ewgi_api.erl:55: The call gb_trees:to_list({non_neg_integer(),'nil' | {_,_,_,_}}) does not have an opaque term of type gb_tree() as 1st argument ewgi_testapp.erl:35: The call ewgi_testapp:htmlise_data("request_data",{non_neg_integer(),'nil' | {_,_,_,_}}) will never return since it differs in the 2nd argument from the success typing arguments: ([95 | 97 | 100 | 101 | 104 | 112 | 113 | 114 | 115 | 116 | 117,...],[{_,_}]) ewgi_testapp.erl:43: The call gb_trees:to_list(T::{non_neg_integer(),'nil' | {_,_,_,_}}) does not have an opaque term of type gb_tree() as 1st argument