diff --git a/src/aeso_ast_to_fcode.erl b/src/aeso_ast_to_fcode.erl
index c2bbe41..c2cf586 100644
--- a/src/aeso_ast_to_fcode.erl
+++ b/src/aeso_ast_to_fcode.erl
@@ -160,7 +160,7 @@
                   context           => context(),
                   vars              => [var_name()],
                   functions         := #{ fun_name() => fun_def() },
-                  saved_fresh_names := #{ var_name() => var_name() }
+                  saved_fresh_names => #{ var_name() => var_name() }
                }.
 
 -define(HASH_BYTES, 32).
@@ -171,8 +171,7 @@
 %% and produces Fate intermediate code.
 -spec ast_to_fcode(aeso_syntax:ast(), [option()]) -> {env(), fcode()}.
 ast_to_fcode(Code, Options) ->
-    init_fresh_names(),
-    init_saved_fresh_names(),
+    init_fresh_names(Options),
     {Env1, FCode1} = to_fcode(init_env(Options), Code),
     FCode2 = optimize(FCode1, Options),
     Env2 = Env1#{ child_con_env :=
@@ -180,9 +179,12 @@ ast_to_fcode(Code, Options) ->
                         fun (_, FC) -> optimize(FC, Options) end,
                         maps:get(child_con_env, Env1)
                        )},
-    Env3 = Env2#{ saved_fresh_names := get(saved_fresh_names) },
-    clear_fresh_names(),
-    clear_saved_fresh_names(),
+    Env3 =
+        case proplists:get_value(debug_info, Options, false) of
+            true  -> Env2#{ saved_fresh_names => get(saved_fresh_names) };
+            false -> Env2
+        end,
+    clear_fresh_names(Options),
     {Env3, FCode2}.
 
 optimize(FCode1, Options) ->
@@ -1733,10 +1735,12 @@ resolve_fun(#{ fun_env := Funs, builtins := Builtin } = Env, Q) ->
         {{Fun, Ar}, _}         -> {def_u, Fun, Ar}
     end.
 
-init_fresh_names() ->
+init_fresh_names(Options) ->
+    proplists:get_value(debug_info, Options, false) andalso init_saved_fresh_names(),
     put('%fresh', 0).
 
-clear_fresh_names() ->
+clear_fresh_names(Options) ->
+    proplists:get_value(debug_info, Options, false) andalso clear_saved_fresh_names(),
     erase('%fresh').
 
 init_saved_fresh_names() ->
@@ -1748,8 +1752,10 @@ clear_saved_fresh_names() ->
 -spec fresh_name_save(string()) -> var_name().
 fresh_name_save(Name) ->
     Fresh = fresh_name(),
-    Old = get(saved_fresh_names),
-    put(saved_fresh_names, Old#{Fresh => Name}),
+    case get(saved_fresh_names) of
+        undefined -> ok;
+        Old       -> put(saved_fresh_names, Old#{Fresh => Name})
+    end,
     Fresh.
 
 -spec fresh_name() -> var_name().
diff --git a/src/aeso_compiler.erl b/src/aeso_compiler.erl
index 389d057..31b4ef8 100644
--- a/src/aeso_compiler.erl
+++ b/src/aeso_compiler.erl
@@ -112,9 +112,11 @@ from_string(ContractString, Options) ->
 
 from_string1(ContractString, Options) ->
     #{ fcode := FCode
-     , fcode_env := #{child_con_env := ChildContracts, saved_fresh_names := SavedFreshNames}
+     , fcode_env := FCodeEnv
      , folded_typed_ast := FoldedTypedAst
      , warnings := Warnings } = string_to_code(ContractString, Options),
+    #{ child_con_env := ChildContracts } = FCodeEnv,
+    SavedFreshNames = maps:get(saved_fresh_names, FCodeEnv, #{}),
     {FateCode, VarsRegs} = aeso_fcode_to_fate:compile(ChildContracts, FCode, SavedFreshNames, Options),
     pp_assembler(FateCode, Options),
     ByteCode = aeb_fate_code:serialize(FateCode, []),
@@ -126,10 +128,15 @@ from_string1(ContractString, Options) ->
             fate_code => FateCode,
             abi_version => aeb_fate_abi:abi_version(),
             payable => maps:get(payable, FCode),
-            variables_registers => VarsRegs,
             warnings => Warnings
            },
-    {ok, maybe_generate_aci(Res, FoldedTypedAst, Options)}.
+    ResDbg = Res#{variables_registers => VarsRegs},
+    FinalRes =
+        case proplists:get_value(debug_info, Options, false) of
+            true  -> ResDbg;
+            false -> Res
+        end,
+    {ok, maybe_generate_aci(FinalRes, FoldedTypedAst, Options)}.
 
 maybe_generate_aci(Result, FoldedTypedAst, Options) ->
     case proplists:get_value(aci, Options) of
@@ -184,9 +191,9 @@ check_call1(ContractString0, FunName, Args, Options) ->
     try
         %% First check the contract without the __call function
         #{fcode := OrgFcode
-        , fcode_env := #{child_con_env := ChildContracts, saved_fresh_names := SavedFreshNames}
+        , fcode_env := #{child_con_env := ChildContracts}
         , ast := Ast} = string_to_code(ContractString0, Options),
-        {FateCode, _VarsRegs} = aeso_fcode_to_fate:compile(ChildContracts, OrgFcode, SavedFreshNames, []),
+        {FateCode, _} = aeso_fcode_to_fate:compile(ChildContracts, OrgFcode, #{}, []),
         %% collect all hashes and compute the first name without hash collision to
         SymbolHashes = maps:keys(aeb_fate_code:symbols(FateCode)),
         CallName = first_none_match(?CALL_NAME, SymbolHashes,
diff --git a/src/aeso_fcode_to_fate.erl b/src/aeso_fcode_to_fate.erl
index 59f1f72..ebc4ebf 100644
--- a/src/aeso_fcode_to_fate.erl
+++ b/src/aeso_fcode_to_fate.erl
@@ -125,7 +125,9 @@ function_to_scode(ChildContracts, ContractName, Functions, Name, Attrs0, Args, B
     {ArgTypes, ResType1} = typesig_to_scode(Args, ResType),
     Attrs = Attrs0 -- [stateful], %% Only track private and payable from here.
     Env = init_env(ChildContracts, ContractName, Functions, Name, Args, SavedFreshNames, Options),
-    [ add_variables_register(Env, Arg, Register) || {Arg, Register} <- Env#env.vars ],
+    [ add_variables_register(Env, Arg, Register) ||
+        proplists:get_value(debug_info, Options, false),
+        {Arg, Register} <- Env#env.vars ],
     SCode = to_scode(Env, Body),
     {Attrs, {ArgTypes, ResType1}, SCode}.
 
@@ -205,7 +207,7 @@ next_var(#env{ vars = Vars }) ->
     1 + lists:max([-1 | [J || {_, {var, J}} <- Vars]]).
 
 bind_var(Name, Var, Env = #env{ vars = Vars }) ->
-    add_variables_register(Env, Name, Var),
+    proplists:get_value(debug_info, Env#env.options, false) andalso add_variables_register(Env, Name, Var),
     Env#env{ vars = [{Name, Var} | Vars] }.
 
 bind_local(Name, Env) ->