Ltac make_cs_preserve' :=
 match goal with |- change_composite_env ?a ?b =>
  make_cs_preserve a b
end.Instance CompSpecs : compspecs.Instance CompSpecs_Preserve: change_composite_env
      spec_hmac.CompSpecs CompSpecs := ltac:(make_cs_preserve').Instance CompSpecs_Preserve': change_composite_env 
             CompSpecs spec_hmac.CompSpecs := ltac:(make_cs_preserve').

Lemma change_compspecs_data_block: forall sh v, @data_block spec_hmac.CompSpecs sh v = @data_block CompSpecs sh v.