Module TemplateArity

type template_binder = {
bind_sort : Sorts.t;
default : Sorts.t;
}

NB: the types and rel_contexts may mention previous args eg "sigT : forall A, (A -> Type) -> Type" is "TemplateArg (, u, TemplateArg (_:Rel 1, v, IndType (_, , Type@max(u,v))))" note the "Rel 1"

val get_template_arity : Environ.env -> Names.inductive -> ctoropt:int option -> template_arity