behaviour() = atom()
dial_warn_tag() = warn_return_no_exit
| warn_return_only_exit
| warn_not_called
| warn_non_proper_list
| warn_matching
| warn_opaque
| warn_fun_app
| warn_failing_call
| warn_bin_construction
| warn_contract_types
| warn_contract_syntax
| warn_contract_not_equal
| warn_contract_subtype
| warn_contract_supertype
| warn_callgraph
| warn_umatched_return
| warn_race_condition
| warn_behaviour
| warn_contract_range
| warn_undefined_callbacks
| warn_unknown