diff --git a/include/cubescript/cubescript.hh b/include/cubescript/cubescript.hh
index 21a62ce8..a31d67a8 100644
--- a/include/cubescript/cubescript.hh
+++ b/include/cubescript/cubescript.hh
@@ -385,7 +385,14 @@ struct OSTD_EXPORT CsState {
         }, error, stack, &func);
     }
 
-    void error(CsString msg);
+    void error(ostd::ConstCharRange msg);
+
+    template<typename ...A>
+    void error(ostd::ConstCharRange msg, A &&...args) {
+        auto app = ostd::appender<CsString>();
+        ostd::format(app, msg, ostd::forward<A>(args)...);
+        error(app.get());
+    }
 
     void clear_override(CsIdent &id);
     void clear_overrides();
diff --git a/src/cs_vm.cc b/src/cs_vm.cc
index 18b53f04..391c3a34 100644
--- a/src/cs_vm.cc
+++ b/src/cs_vm.cc
@@ -132,29 +132,6 @@ CsStackState cs_save_stack(CsState &cs) {
     return CsStackState(ret, total != dalias->get_value());
 }
 
-void cs_debug_alias(CsState &cs) {
-    CsIvar *dalias = static_cast<CsIvar *>(cs.identmap[DbgaliasIdx]);
-    if (!dalias->get_value()) {
-        return;
-    }
-    int total = 0, depth = 0;
-    for (CsIdentLink *l = cs.p_callstack; l != &cs.noalias; l = l->next) {
-        total++;
-    }
-    for (CsIdentLink *l = cs.p_callstack; l != &cs.noalias; l = l->next) {
-        CsIdent *id = l->id;
-        ++depth;
-        if (depth < dalias->get_value()) {
-            cs.get_err().writefln("  %d) %s", total - depth + 1, id->get_name());
-        } else if (l->next == &cs.noalias) {
-            cs.get_err().writefln(
-                depth == dalias->get_value() ? "  %d) %s" : "  ..%d) %s",
-                total - depth + 1, id->get_name()
-            );
-        }
-    }
-}
-
 static void bcode_ref(ostd::Uint32 *code) {
     if (!code) {
         return;
diff --git a/src/cs_vm.hh b/src/cs_vm.hh
index c8c7c5e5..47dd07ce 100644
--- a/src/cs_vm.hh
+++ b/src/cs_vm.hh
@@ -103,8 +103,6 @@ ostd::ConstCharRange cs_debug_line(
     ostd::ConstCharRange p, ostd::ConstCharRange fmt, ostd::CharRange buf
 );
 
-void cs_debug_alias(CsState &cs);
-
 CsStackState cs_save_stack(CsState &cs);
 
 template<typename ...A>
@@ -113,7 +111,8 @@ void cs_debug_code(CsState &cs, ostd::ConstCharRange fmt, A &&...args) {
         return;
     }
     cs.get_err().writefln(fmt, ostd::forward<A>(args)...);
-    cs_debug_alias(cs);
+    auto st = cs_save_stack(cs);
+    cscript::util::print_stack(cs.get_err().iter(), st);
 }
 
 template<typename ...A>
@@ -128,7 +127,8 @@ void cs_debug_code_line(
         cs_debug_line(p, fmt, ostd::CharRange(buf.data(), buf.size())),
         ostd::forward<A>(args)...
     );
-    cs_debug_alias(cs);
+    auto st = cs_save_stack(cs);
+    cscript::util::print_stack(cs.get_err().iter(), st);
 }
 
 struct GenState {
diff --git a/src/cubescript.cc b/src/cubescript.cc
index 81e39a46..c34762f8 100644
--- a/src/cubescript.cc
+++ b/src/cubescript.cc
@@ -442,12 +442,12 @@ bool CsState::ipcall(
     return true;
 }
 
-void CsState::error(CsString msg) {
+void CsState::error(ostd::ConstCharRange msg) {
     if (protect) {
-        throw CsErrorException(ostd::move(msg), cs_save_stack(*this));
+        throw CsErrorException(msg, cs_save_stack(*this));
     } else {
         if (p_panicfunc) {
-            p_panicfunc(ostd::move(msg), cs_save_stack(*this));
+            p_panicfunc(msg, cs_save_stack(*this));
         }
         exit(EXIT_FAILURE);
     }