Augment_specialised_args.What_to_specialiseval create : set_of_closures:Flambda.set_of_closures -> tval new_specialised_arg : 
  t ->
  fun_var:Variable.t ->
  group:Variable.t ->
  definition:Definition.t ->
  tval make_direct_call_surrogate_for : t -> fun_var:Variable.t -> t