anchor.diff:     and are named embed_x, unembed_x *)
   let rec mk_tac_embedding_path (m: emb_decl) (t: term): mlexpr' =
       match (FStar.Syntax.Subst.compress t).n with
  -    | Tm_fvar fv when fv_eq_lid fv PC.int_lid -> mk_embedding m "int"
  -    | Tm_fvar fv when fv_eq_lid fv PC.bool_lid -> mk_embedding m "bool"
  -    | Tm_fvar fv when fv_eq_lid fv PC.unit_lid -> mk_embedding m "unit"
  -    | Tm_fvar fv when fv_eq_lid fv PC.string_lid -> mk_embedding m "string"
  +    | Tm_fvar fv when fv_eq_lid fv PC.int_lid -> mk_basic_embedding m "int"
  +    | Tm_fvar fv when fv_eq_lid fv PC.bool_lid -> mk_basic_embedding m "bool"
  +    | Tm_fvar fv when fv_eq_lid fv PC.unit_lid -> mk_basic_embedding m "unit"
  +    | Tm_fvar fv when fv_eq_lid fv PC.string_lid -> mk_basic_embedding m "string"
       | Tm_fvar fv when fv_eq_lid fv (RD.fstar_refl_types_lid "binder") -> mk_embedding m "binder"
       | Tm_fvar fv when fv_eq_lid fv (RD.fstar_refl_types_lid "term") -> mk_embedding m "term"
       | Tm_fvar fv when fv_eq_lid fv (RD.fstar_refl_types_lid "fv") -> mk_embedding m "fvar"
  
positive.code: 
  let rec mk_tac_param_type (t: term): mlexpr' =
      match (FStar.Syntax.Subst.compress t).n with
      | Tm_fvar fv when fv_eq_lid fv PC.int_lid -> fstar_tc_common_prefix "t_int"
      | Tm_fvar fv when fv_eq_lid fv PC.bool_lid -> fstar_tc_common_prefix "t_bool"
      | Tm_fvar fv when fv_eq_lid fv PC.unit_lid -> fstar_tc_common_prefix "t_unit"
      | Tm_fvar fv when fv_eq_lid fv PC.string_lid -> fstar_tc_common_prefix "t_string"
      | Tm_fvar fv when fv_eq_lid fv (RD.fstar_refl_types_lid "binder") -> fstar_refl_data_prefix "t_binder"
      | Tm_fvar fv when fv_eq_lid fv (RD.fstar_refl_types_lid "term") -> fstar_refl_data_prefix "t_term"
      | Tm_fvar fv when fv_eq_lid fv (RD.fstar_refl_types_lid "fv") -> fstar_refl_data_prefix "t_fv"
  
negative.code: let str_to_name s = lid_to_name (lid_of_str s)
  let str_to_top_name s = lid_to_top_name (lid_of_str s)
  
  let fstar_syn_syn_prefix s = str_to_name ("FStar_Syntax_Syntax." ^ s)
  let fstar_tc_common_prefix s = str_to_name ("FStar_TypeChecker_Common." ^ s)
  let fstar_refl_basic_prefix s = str_to_name ("FStar_Reflection_Basic." ^ s)
  let fstar_refl_data_prefix s = str_to_name ("FStar_Reflection_Data." ^ s)
  let fstar_emb_basic_prefix s = str_to_name ("FStar_Syntax_Embeddings." ^ s)
  let mk_basic_embedding (m: emb_decl) (s: string) =
      match m with
      | Embed -> fstar_emb_basic_prefix ("embed_" ^ s)
      | Unembed -> fstar_emb_basic_prefix ("unembed_" ^ s)
  let mk_embedding (m: emb_decl) (s: string) =
      match m with
      | Embed -> fstar_refl_basic_prefix ("embed_" ^ s)
  