Procname.Hack
Hack procedure is identified by the class and function names and its arity. The arity can be absent for external function declarations of the form declare F.f(...): ...
TODO(arr): consider making the arity non-optional if we remove function declarations from the Tenv
val get_class_name_as_a_string : t -> string option
val is_xinit : t -> bool
val belongs_to_static_companion : t -> bool