diff --git a/src/cs_error.cc b/src/cs_error.cc
index eb70973..05e2396 100644
--- a/src/cs_error.cc
+++ b/src/cs_error.cc
@@ -84,9 +84,7 @@ LIBCUBESCRIPT_EXPORT char *error::request_buf(
 }
 
 LIBCUBESCRIPT_EXPORT stack_state error::save_stack(thread_state &ts) {
-    integer_var *dalias = static_cast<integer_var *>(
-        ts.istate->identmap[ID_IDX_DBGALIAS]
-    );
+    integer_var *dalias = ts.istate->ivar_dbgalias;
     auto dval = std::clamp(
         dalias->get_value(), integer_type(0), integer_type(1000)
     );
diff --git a/src/cs_gen.hh b/src/cs_gen.hh
index f963bc2..c4e4a49 100644
--- a/src/cs_gen.hh
+++ b/src/cs_gen.hh
@@ -15,10 +15,6 @@
 
 namespace cubescript {
 
-static constexpr int ID_IDX_DUMMY = MAX_ARGUMENTS;
-static constexpr int ID_IDX_NUMARGS = MAX_ARGUMENTS + 1;
-static constexpr int ID_IDX_DBGALIAS = MAX_ARGUMENTS + 2;
-
 struct codegen_state {
     thread_state &ts;
     codegen_state *prevps;
@@ -112,7 +108,7 @@ struct codegen_state {
     }
 
     void gen_ident() {
-        gen_ident(ts.istate->identmap[ID_IDX_DUMMY]);
+        gen_ident(ts.istate->id_dummy);
     }
 
     void gen_ident(std::string_view word) {
diff --git a/src/cs_state.cc b/src/cs_state.cc
index 5195a07..1591b8a 100644
--- a/src/cs_state.cc
+++ b/src/cs_state.cc
@@ -120,20 +120,10 @@ state::state(alloc_func func, void *data) {
         );
     }
 
-    ident *id = statep->new_ident(*this, "//dummy", IDENT_FLAG_UNKNOWN);
-    if (id->get_index() != ID_IDX_DUMMY) {
-        throw internal_error{"invalid dummy index"};
-    }
+    statep->id_dummy = statep->new_ident(*this, "//dummy", IDENT_FLAG_UNKNOWN);
 
-    id = new_ivar("numargs", 0, true);
-    if (id->get_index() != ID_IDX_NUMARGS) {
-        throw internal_error{"invalid numargs index"};
-    }
-
-    id = new_ivar("dbgalias", 4);
-    if (id->get_index() != ID_IDX_DBGALIAS) {
-        throw internal_error{"invalid dbgalias index"};
-    }
+    statep->ivar_numargs  = new_ivar("numargs", 0, true);
+    statep->ivar_dbgalias = new_ivar("dbgalias", 4);
 
     /* default handlers for variables */
 
diff --git a/src/cs_state.hh b/src/cs_state.hh
index aed3eec..13195d1 100644
--- a/src/cs_state.hh
+++ b/src/cs_state.hh
@@ -52,6 +52,11 @@ struct internal_state {
     string_pool *strman;
     empty_block *empty;
 
+    ident *id_dummy;
+
+    integer_var *ivar_numargs;
+    integer_var *ivar_dbgalias;
+
     command *cmd_ivar;
     command *cmd_fvar;
     command *cmd_svar;
diff --git a/src/cs_vm.cc b/src/cs_vm.cc
index 7233454..dfabc06 100644
--- a/src/cs_vm.cc
+++ b/src/cs_vm.cc
@@ -152,7 +152,7 @@ void exec_command(
                     if (rep) {
                         break;
                     }
-                    args[i].set_ident(ts.istate->identmap[ID_IDX_DUMMY]);
+                    args[i].set_ident(ts.istate->id_dummy);
                     fakeargs++;
                 } else {
                     args[i].force_ident(*ts.pstate);
@@ -217,9 +217,7 @@ bool exec_alias(
     }
     /* excess arguments get ignored (make error maybe?) */
     callargs = std::min(callargs, MAX_ARGUMENTS);
-    integer_var *anargs = static_cast<integer_var *>(
-        ts.istate->identmap[ID_IDX_NUMARGS]
-    );
+    integer_var *anargs = ts.istate->ivar_numargs;
     argset uargs{};
     std::size_t noff = ts.idstack.size();
     for(std::size_t i = 0; i < callargs; i++) {
@@ -771,7 +769,7 @@ std::uint32_t *vm_exec(
             }
             case BC_INST_IDENT_U: {
                 any_value &arg = args.back();
-                ident *id = ts.istate->identmap[ID_IDX_DUMMY];
+                ident *id = ts.istate->id_dummy;
                 if (arg.get_type() == value_type::STRING) {
                     id = ts.istate->new_ident(
                         cs, arg.get_str(), IDENT_FLAG_UNKNOWN