anchor.diff:        EBufFree (translate_expr env e2)
   
     (* Generic buffer operations. *)
  -  | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ e1; e2; _e3 ]) when (string_of_mlpath p = "FStar.Buffer.sub" || string_of_mlpath p = "LowStar.Buffer.sub") ->
  +  | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ e1; e2; _e3 ]) when (string_of_mlpath p = "FStar.Buffer.sub") ->
         EBufSub (translate_expr env e1, translate_expr env e2)
   
  -  | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ e1; e2; _e3; _e4 ]) when string_of_mlpath p = "LowStar.Monotonic.Buffer.msub" ->
  +  | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ e1; e2; _e3 ]) when string_of_mlpath p = "LowStar.Monotonic.Buffer.msub" ->
         EBufSub (translate_expr env e1, translate_expr env e2)
  -
   
     | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ e1; e2 ]) when (string_of_mlpath p = "FStar.Buffer.join") ->
         (translate_expr env e1)
   
  -  | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ e1; e2 ]) when (string_of_mlpath p = "FStar.Buffer.offset" || string_of_mlpath p = "LowStar.Buffer.offset") ->
  +  | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ e1; e2 ]) when (string_of_mlpath p = "FStar.Buffer.offset") ->
         EBufSub (translate_expr env e1, translate_expr env e2)
   
  -  | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ e1; e2; _e3 ]) when string_of_mlpath p = "LowStar.Monotonic.Buffer.moffset" ->
  +  | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ e1; e2 ]) when string_of_mlpath p = "LowStar.Monotonic.Buffer.moffset" ->
         EBufSub (translate_expr env e1, translate_expr env e2)
   
     | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ e1; e2; e3 ])
  
positive.code:       EBufCreate (Eternal, translate_expr env init, EConstant (UInt32, "1"))
  
    | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) }, [ _e0; e1; e2 ])
      when (string_of_mlpath p = "FStar.Buffer.rcreate" || string_of_mlpath p = "LowStar.Buffer.gcmalloc" ||
            string_of_mlpath p = "LowStar.Monotonic.Buffer.mgcmalloc") ->
        EBufCreate (Eternal, translate_expr env e1, translate_expr env e2)
  
    | MLE_App ({ expr = MLE_TApp({ expr = MLE_Name p }, _) } , [ _rid; init ])
  
negative.code:   | MLTY_Named ([arg; _; _], p) when
      Syntax.string_of_mlpath p = "LowStar.Monotonic.Buffer.mbuffer" -> TBuf (translate_type env arg)
    | MLTY_Named ([arg], p) when
      Syntax.string_of_mlpath p = "FStar.Buffer.buffer" ||
      Syntax.string_of_mlpath p = "LowStar.Buffer.buffer" ||
      Syntax.string_of_mlpath p = "FStar.HyperStack.reference" ||
      Syntax.string_of_mlpath p = "FStar.HyperStack.stackref" ||
      Syntax.string_of_mlpath p = "FStar.HyperStack.ref" ||
  