Instance Linker_composite_defs : Linker (list composite_definition) := {
  link := link_composite_defs;
  linkorder := @List.incl composite_definition
}.

Lemma composite_consistent_unique: forall env co1 co2, composite_consistent env co1 -> composite_consistent env co2 -> co_su co1 = co_su co2 -> co_members co1 = co_members co2 -> co_attr co1 = co_attr co2 -> co1 = co2.