Parameter MC_order :  core_data -> core_data -> Prop.Parameter MC_wellfounded: well_founded MC_order.Definition MC_measure (q:CSharpMin_core): nat :=
  match q with
  | CSharpMin_State fn s k e lenv => seq_left_depth s
  | _ => O
  end.

Lemma MS_step_case_ReturnNone: forall cenv sz f tfn j m tm e lenv te sp lo hi cs k tk xenv m' (Freelist: Mem.free_list m (blocks_of_env e) = Some m') (TRF : transl_funbody cenv sz f = OK tfn) (MINJ : Mem.inject j m tm) (MCS : match_callstack prog j m tm (Frame cenv tfn e lenv te sp lo hi :: cs) (Mem.nextblock m) (Mem.nextblock tm)) (MK : match_cont tk k cenv xenv cs) (*NEW:*) (PG: meminj_preserves_globals ge j), exists c2' : CMin_core, exists m2' : mem, corestep_plus CMin_core_sem tge (CMin_State tfn (Sreturn None) k (Vptr sp Int.zero) te) tm c2' m2' /\ match_cores (CSharpMin_Returnstate Vundef (Csharpminor.call_cont tk)) j (CSharpMin_Returnstate Vundef (Csharpminor.call_cont tk)) m' c2' m2'.