diff --git a/src/stage0/init/lean/compiler/ir/borrow.c b/src/stage0/init/lean/compiler/ir/borrow.c
index cfc4170c8e..77bacc2711 100644
--- a/src/stage0/init/lean/compiler/ir/borrow.c
+++ b/src/stage0/init/lean/compiler/ir/borrow.c
@@ -72,7 +72,6 @@ lean_object* l_Array_mforAux___main___at_Lean_IR_Borrow_InitParamMap_visitDecls_
 lean_object* l_Lean_IR_Borrow_applyParamMap___boxed(lean_object*, lean_object*);
 lean_object* l_Lean_IR_Borrow_isOwned___boxed(lean_object*, lean_object*, lean_object*);
 lean_object* l_RBNode_insert___at_Lean_IR_mkIndexSet___spec__1(lean_object*, lean_object*, lean_object*);
-lean_object* l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__4;
 lean_object* l_Lean_IR_Borrow_collectDecl(lean_object*, lean_object*, lean_object*);
 lean_object* l_Nat_repr(lean_object*);
 lean_object* l_Lean_IR_Borrow_Key_HasBeq;
@@ -161,6 +160,7 @@ extern lean_object* l_Lean_Name_toString___closed__1;
 uint8_t lean_nat_dec_le(lean_object*, lean_object*);
 size_t lean_usize_of_nat(lean_object*);
 lean_object* l_Lean_IR_Borrow_mkInitParamMap___closed__1;
+extern lean_object* l_panicWithPos___rarg___closed__2;
 lean_object* l_Lean_IR_Borrow_whileModifingOwnedAux___main___at_Lean_IR_Borrow_collectDecl___spec__1(lean_object*, lean_object*, lean_object*, lean_object*);
 lean_object* l_Lean_IR_Borrow_collectDecls___boxed(lean_object*, lean_object*, lean_object*);
 lean_object* l_AssocList_replace___main___at_Lean_IR_Borrow_InitParamMap_visitFnBody___main___spec__6(lean_object*, lean_object*, lean_object*);
@@ -324,16 +324,8 @@ return x_2;
 lean_object* _init_l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__3() {
 _start:
 {
-lean_object* x_1; 
-x_1 = lean_mk_string(":");
-return x_1;
-}
-}
-lean_object* _init_l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__4() {
-_start:
-{
 lean_object* x_1; lean_object* x_2; 
-x_1 = l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__3;
+x_1 = l_panicWithPos___rarg___closed__2;
 x_2 = lean_alloc_ctor(2, 1, 0);
 lean_ctor_set(x_2, 0, x_1);
 return x_2;
@@ -405,7 +397,7 @@ x_23 = l_Lean_Name_toString___closed__1;
 x_24 = l_Lean_Name_toStringWithSep___main(x_23, x_21);
 x_25 = lean_alloc_ctor(2, 1, 0);
 lean_ctor_set(x_25, 0, x_24);
-x_26 = l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__4;
+x_26 = l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__3;
 x_27 = lean_alloc_ctor(4, 2, 1);
 lean_ctor_set(x_27, 0, x_25);
 lean_ctor_set(x_27, 1, x_26);
@@ -3876,8 +3868,6 @@ l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__2
 lean_mark_persistent(l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__2);
 l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__3 = _init_l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__3();
 lean_mark_persistent(l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__3);
-l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__4 = _init_l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__4();
-lean_mark_persistent(l_AssocList_mfoldl___main___at_Lean_IR_Borrow_ParamMap_fmt___spec__1___closed__4);
 l_Lean_IR_Borrow_ParamMap_fmt___closed__1 = _init_l_Lean_IR_Borrow_ParamMap_fmt___closed__1();
 lean_mark_persistent(l_Lean_IR_Borrow_ParamMap_fmt___closed__1);
 l_Lean_IR_Borrow_ParamMap_fmt___closed__2 = _init_l_Lean_IR_Borrow_ParamMap_fmt___closed__2();
diff --git a/src/stage0/init/lean/compiler/ir/emitc.c b/src/stage0/init/lean/compiler/ir/emitc.c
index 1639151143..8558a13351 100644
--- a/src/stage0/init/lean/compiler/ir/emitc.c
+++ b/src/stage0/init/lean/compiler/ir/emitc.c
@@ -457,6 +457,7 @@ lean_object* lean_nat_div(lean_object*, lean_object*);
 lean_object* l_Lean_IR_EmitC_emitMainFn___closed__21;
 lean_object* l_Lean_IR_EmitC_emitDeclInit(lean_object*, lean_object*, lean_object*);
 lean_object* l_Lean_IR_EmitC_emitMainFn___closed__37;
+extern lean_object* l_panicWithPos___rarg___closed__2;
 lean_object* l_Nat_mforAux___main___at_Lean_IR_EmitC_emitJmp___spec__1___closed__1;
 lean_object* l_Lean_IR_EmitC_getJPParams___boxed(lean_object*, lean_object*, lean_object*);
 lean_object* l_Lean_IR_EmitC_emitIf(lean_object*, lean_object*, uint8_t, lean_object*, lean_object*, lean_object*, lean_object*, lean_object*);
@@ -513,7 +514,6 @@ lean_object* l_Lean_IR_EmitC_emitExternDeclAux___boxed(lean_object*, lean_object
 lean_object* l_Lean_IR_EmitC_toCType___closed__1;
 lean_object* l_Lean_IR_EmitC_emitFileHeader___closed__5;
 lean_object* l_Lean_IR_EmitC_emitCase___closed__2;
-lean_object* l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__2;
 lean_object* l_Lean_IR_EmitC_emitCInitName___boxed(lean_object*, lean_object*, lean_object*);
 extern lean_object* l_Unit_HasRepr___closed__1;
 lean_object* l_Lean_IR_EmitC_toStringArgs(lean_object*);
@@ -7616,14 +7616,6 @@ lean_object* _init_l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1_
 _start:
 {
 lean_object* x_1; 
-x_1 = lean_mk_string(":");
-return x_1;
-}
-}
-lean_object* _init_l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__2() {
-_start:
-{
-lean_object* x_1; 
 x_1 = lean_mk_string("default: ");
 return x_1;
 }
@@ -7694,7 +7686,7 @@ x_24 = lean_string_append(x_20, x_23);
 x_25 = l_Nat_repr(x_22);
 x_26 = lean_string_append(x_24, x_25);
 lean_dec(x_25);
-x_27 = l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__1;
+x_27 = l_panicWithPos___rarg___closed__2;
 x_28 = lean_string_append(x_26, x_27);
 x_29 = l_IO_println___rarg___closed__1;
 x_30 = lean_string_append(x_28, x_29);
@@ -7772,7 +7764,7 @@ x_46 = lean_string_append(x_43, x_45);
 x_47 = l_Nat_repr(x_44);
 x_48 = lean_string_append(x_46, x_47);
 lean_dec(x_47);
-x_49 = l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__1;
+x_49 = l_panicWithPos___rarg___closed__2;
 x_50 = lean_string_append(x_48, x_49);
 x_51 = l_IO_println___rarg___closed__1;
 x_52 = lean_string_append(x_50, x_51);
@@ -7849,7 +7841,7 @@ lean_object* x_66; lean_object* x_67; lean_object* x_68; lean_object* x_69; lean
 x_66 = lean_ctor_get(x_5, 1);
 x_67 = lean_ctor_get(x_5, 0);
 lean_dec(x_67);
-x_68 = l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__2;
+x_68 = l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__1;
 x_69 = lean_string_append(x_66, x_68);
 x_70 = l_IO_println___rarg___closed__1;
 x_71 = lean_string_append(x_69, x_70);
@@ -7919,7 +7911,7 @@ lean_object* x_84; lean_object* x_85; lean_object* x_86; lean_object* x_87; lean
 x_84 = lean_ctor_get(x_5, 1);
 lean_inc(x_84);
 lean_dec(x_5);
-x_85 = l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__2;
+x_85 = l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__1;
 x_86 = lean_string_append(x_84, x_85);
 x_87 = l_IO_println___rarg___closed__1;
 x_88 = lean_string_append(x_86, x_87);
@@ -19939,7 +19931,7 @@ x_24 = lean_string_append(x_23, x_22);
 lean_dec(x_22);
 x_25 = lean_string_append(x_20, x_24);
 lean_dec(x_24);
-x_26 = l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__1;
+x_26 = l_panicWithPos___rarg___closed__2;
 x_27 = lean_string_append(x_25, x_26);
 x_28 = l_IO_println___rarg___closed__1;
 x_29 = lean_string_append(x_27, x_28);
@@ -20015,7 +20007,7 @@ x_45 = lean_string_append(x_44, x_43);
 lean_dec(x_43);
 x_46 = lean_string_append(x_42, x_45);
 lean_dec(x_45);
-x_47 = l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__1;
+x_47 = l_panicWithPos___rarg___closed__2;
 x_48 = lean_string_append(x_46, x_47);
 x_49 = l_IO_println___rarg___closed__1;
 x_50 = lean_string_append(x_48, x_49);
@@ -27271,8 +27263,6 @@ l_Lean_IR_EmitC_emitIf___closed__3 = _init_l_Lean_IR_EmitC_emitIf___closed__3();
 lean_mark_persistent(l_Lean_IR_EmitC_emitIf___closed__3);
 l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__1 = _init_l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__1();
 lean_mark_persistent(l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__1);
-l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__2 = _init_l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__2();
-lean_mark_persistent(l_Array_mforAux___main___at_Lean_IR_EmitC_emitCase___spec__1___closed__2);
 l_Lean_IR_EmitC_emitCase___closed__1 = _init_l_Lean_IR_EmitC_emitCase___closed__1();
 lean_mark_persistent(l_Lean_IR_EmitC_emitCase___closed__1);
 l_Lean_IR_EmitC_emitCase___closed__2 = _init_l_Lean_IR_EmitC_emitCase___closed__2();
diff --git a/src/stage0/init/lean/elaborator/term.c b/src/stage0/init/lean/elaborator/term.c
index 37c6bdaf21..07f4e28b91 100644
--- a/src/stage0/init/lean/elaborator/term.c
+++ b/src/stage0/init/lean/elaborator/term.c
@@ -30,7 +30,6 @@ lean_object* l_Lean_Elab_mkExplicitBinder___rarg___closed__4;
 lean_object* l_Lean_Elab_elabList(lean_object*, lean_object*, lean_object*, lean_object*);
 lean_object* l_Lean_Elab_elabTermAux___main___boxed(lean_object*, lean_object*, lean_object*, lean_object*, lean_object*);
 size_t l_USize_shift__right(size_t, size_t);
-extern lean_object* l_Lean_mkErrorStringWithPos___closed__1;
 lean_object* l_Lean_Syntax_mfoldArgsAux___main___at_Lean_Elab_elabList___spec__1___boxed(lean_object*, lean_object*, lean_object*, lean_object*, lean_object*);
 extern lean_object* l_Lean_List_format___rarg___closed__2;
 lean_object* l_Lean_Elab_elabList___closed__3;
@@ -88,6 +87,7 @@ lean_object* l_Array_get(lean_object*, lean_object*, lean_object*, lean_object*)
 lean_object* l_Lean_Elab_elabTerm(lean_object*, lean_object*, lean_object*, lean_object*);
 lean_object* l_Lean_SMap_find___at_Lean_Elab_elabTermAux___main___spec__1(lean_object*, lean_object*);
 extern lean_object* l_Lean_Parser_Term_forall___elambda__1___closed__2;
+extern lean_object* l_panicWithPos___rarg___closed__2;
 extern lean_object* l_Lean_Syntax_asNode___rarg___closed__1;
 lean_object* l_Lean_Elab_mkExplicitBinder___rarg___closed__2;
 lean_object* l_Lean_Elab_elabArrow(lean_object*, lean_object*, lean_object*, lean_object*);
@@ -1552,7 +1552,7 @@ lean_object* _init_l_Lean_Elab_mkExplicitBinder___rarg___closed__2() {
 _start:
 {
 lean_object* x_1; lean_object* x_2; 
-x_1 = l_Lean_mkErrorStringWithPos___closed__1;
+x_1 = l_panicWithPos___rarg___closed__2;
 x_2 = l_Lean_mkAtom___rarg(x_1);
 return x_2;
 }
diff --git a/src/stage0/init/lean/message.c b/src/stage0/init/lean/message.c
index 45fa424e04..e754928438 100644
--- a/src/stage0/init/lean/message.c
+++ b/src/stage0/init/lean/message.c
@@ -17,7 +17,6 @@ lean_object* l_Lean_mkErrorStringWithPos(lean_object*, lean_object*, lean_object
 lean_object* l_Lean_MessageLog_empty;
 lean_object* l_Lean_Message_toString___closed__2;
 lean_object* l_Lean_Message_toString___closed__1;
-lean_object* l_Lean_mkErrorStringWithPos___closed__1;
 lean_object* l_Lean_Message_Inhabited___closed__2;
 lean_object* l_Lean_MessageLog_append(lean_object*, lean_object*);
 extern lean_object* l_EState_Result_toString___rarg___closed__2;
@@ -44,24 +43,17 @@ lean_object* l_Lean_Message_toString(lean_object*);
 lean_object* l_Lean_MessageLog_HasAppend;
 lean_object* l_Lean_MessageLog_isEmpty___boxed(lean_object*);
 lean_object* l_Lean_MessageLog_hasErrors___boxed(lean_object*);
+extern lean_object* l_panicWithPos___rarg___closed__2;
 lean_object* l_Lean_MessageLog_Inhabited;
 uint8_t l_List_foldr___main___at_Lean_MessageLog_hasErrors___spec__1(uint8_t, lean_object*);
 extern lean_object* l_String_splitAux___main___closed__1;
 lean_object* l_Lean_Message_Inhabited___closed__1;
 lean_object* l_Lean_Message_toString___closed__5;
-lean_object* _init_l_Lean_mkErrorStringWithPos___closed__1() {
-_start:
-{
-lean_object* x_1; 
-x_1 = lean_mk_string(":");
-return x_1;
-}
-}
 lean_object* l_Lean_mkErrorStringWithPos(lean_object* x_1, lean_object* x_2, lean_object* x_3, lean_object* x_4) {
 _start:
 {
 lean_object* x_5; lean_object* x_6; lean_object* x_7; lean_object* x_8; lean_object* x_9; lean_object* x_10; lean_object* x_11; lean_object* x_12; lean_object* x_13; lean_object* x_14; 
-x_5 = l_Lean_mkErrorStringWithPos___closed__1;
+x_5 = l_panicWithPos___rarg___closed__2;
 x_6 = lean_string_append(x_1, x_5);
 x_7 = l_Nat_repr(x_2);
 x_8 = lean_string_append(x_6, x_7);
@@ -454,8 +446,6 @@ w = initialize_init_data_tostring(w);
 if (lean_io_result_is_error(w)) return w;
 w = initialize_init_lean_position(w);
 if (lean_io_result_is_error(w)) return w;
-l_Lean_mkErrorStringWithPos___closed__1 = _init_l_Lean_mkErrorStringWithPos___closed__1();
-lean_mark_persistent(l_Lean_mkErrorStringWithPos___closed__1);
 l_Lean_Message_toString___closed__1 = _init_l_Lean_Message_toString___closed__1();
 lean_mark_persistent(l_Lean_Message_toString___closed__1);
 l_Lean_Message_toString___closed__2 = _init_l_Lean_Message_toString___closed__2();
diff --git a/src/stage0/init/lean/parser/parser.c b/src/stage0/init/lean/parser/parser.c
index 8880ed27dc..e5e5001914 100644
--- a/src/stage0/init/lean/parser/parser.c
+++ b/src/stage0/init/lean/parser/parser.c
@@ -138,7 +138,6 @@ lean_object* l_RBNode_ins___main___at_Lean_Parser_TokenMap_insert___spec__6___ra
 extern lean_object* l_Lean_PersistentEnvExtension_inhabited___rarg___closed__3;
 lean_object* l_Lean_Parser_quotedSymbol___elambda__1(uint8_t);
 lean_object* l_Lean_Parser_mkParserContext(lean_object*, lean_object*, lean_object*);
-extern lean_object* l_Lean_mkErrorStringWithPos___closed__1;
 lean_object* l_RBNode_ins___main___at_Lean_Parser_TokenMap_insert___spec__4___rarg(lean_object*, lean_object*, lean_object*);
 extern lean_object* l_Lean_strLitKind___closed__1;
 lean_object* l_AssocList_mfoldl___main___at_Lean_Parser_nodeInfo___elambda__1___spec__5(lean_object*, lean_object*);
@@ -766,6 +765,7 @@ lean_object* l_Lean_Parser_Error_HasBeq;
 lean_object* l_Lean_Parser_declareTrailingBuiltinParser___closed__2;
 lean_object* lean_string_utf8_byte_size(lean_object*);
 uint8_t l_Lean_Syntax_isMissing___rarg(lean_object*);
+extern lean_object* l_panicWithPos___rarg___closed__2;
 lean_object* l_Lean_Parser_rawIdent(uint8_t);
 lean_object* l_Lean_Parser_mkBuiltinTokenTable(lean_object*);
 lean_object* l_Lean_Parser_rawIdent___lambda__1___boxed(lean_object*, lean_object*, lean_object*);
@@ -1125,7 +1125,7 @@ lean_dec(x_1);
 x_13 = lean_ctor_get(x_2, 0);
 lean_inc(x_13);
 lean_dec(x_2);
-x_14 = l_Lean_mkErrorStringWithPos___closed__1;
+x_14 = l_panicWithPos___rarg___closed__2;
 x_15 = lean_string_append(x_12, x_14);
 x_16 = l_Nat_repr(x_13);
 x_17 = lean_string_append(x_15, x_16);
@@ -1144,7 +1144,7 @@ lean_dec(x_2);
 x_20 = lean_ctor_get(x_11, 0);
 lean_inc(x_20);
 lean_dec(x_11);
-x_21 = l_Lean_mkErrorStringWithPos___closed__1;
+x_21 = l_panicWithPos___rarg___closed__2;
 x_22 = lean_string_append(x_18, x_21);
 x_23 = l_Nat_repr(x_19);
 x_24 = lean_string_append(x_22, x_23);
diff --git a/src/stage0/init/util.c b/src/stage0/init/util.c
index 666de35118..26967820b3 100644
--- a/src/stage0/init/util.c
+++ b/src/stage0/init/util.c
@@ -1,6 +1,6 @@
 // Lean compiler output
 // Module: init.util
-// Imports: init.data.string.basic
+// Imports: init.data.string.basic init.data.tostring
 #include "runtime/lean.h"
 #if defined(__clang__)
 #pragma clang diagnostic ignored "-Wunused-parameter"
@@ -14,13 +14,23 @@
 extern "C" {
 #endif
 lean_object* l_unsafeCast(lean_object*, lean_object*, lean_object*, lean_object*);
+lean_object* l_panicWithPos___rarg___boxed(lean_object*, lean_object*, lean_object*, lean_object*, lean_object*);
 lean_object* l_dbgTrace(lean_object*, lean_object*, lean_object*);
+lean_object* l_panic___boxed(lean_object*, lean_object*, lean_object*);
+lean_object* l_Nat_repr(lean_object*);
+lean_object* l_panicWithPos___rarg___closed__3;
+lean_object* lean_string_append(lean_object*, lean_object*);
 lean_object* l_dbgSleep___boxed(lean_object*, lean_object*, lean_object*);
+lean_object* l_panicWithPos(lean_object*);
+lean_object* l_panicWithPos___rarg___closed__1;
 lean_object* l_dbgTraceIfShared___boxed(lean_object*, lean_object*, lean_object*);
 lean_object* l_dbgSleep(lean_object*, uint32_t, lean_object*);
+lean_object* l_panic(lean_object*, lean_object*, lean_object*);
 lean_object* l_unsafeCast___boxed(lean_object*, lean_object*, lean_object*, lean_object*);
 lean_object* l_dbgTrace___boxed(lean_object*, lean_object*, lean_object*);
+lean_object* l_panicWithPos___rarg___closed__2;
 lean_object* l_dbgTraceIfShared(lean_object*, lean_object*, lean_object*);
+lean_object* l_panicWithPos___rarg(lean_object*, lean_object*, lean_object*, lean_object*, lean_object*);
 lean_object* l_dbgTrace___boxed(lean_object* x_1, lean_object* x_2, lean_object* x_3) {
 _start:
 {
@@ -55,7 +65,80 @@ x_5 = x_4;
 return x_5;
 }
 }
+lean_object* l_panic___boxed(lean_object* x_1, lean_object* x_2, lean_object* x_3) {
+_start:
+{
+lean_object* x_4; 
+x_4 = lean_panic_fn(x_3);
+return x_4;
+}
+}
+lean_object* _init_l_panicWithPos___rarg___closed__1() {
+_start:
+{
+lean_object* x_1; 
+x_1 = lean_mk_string("PANIC at ");
+return x_1;
+}
+}
+lean_object* _init_l_panicWithPos___rarg___closed__2() {
+_start:
+{
+lean_object* x_1; 
+x_1 = lean_mk_string(":");
+return x_1;
+}
+}
+lean_object* _init_l_panicWithPos___rarg___closed__3() {
+_start:
+{
+lean_object* x_1; 
+x_1 = lean_mk_string(": ");
+return x_1;
+}
+}
+lean_object* l_panicWithPos___rarg(lean_object* x_1, lean_object* x_2, lean_object* x_3, lean_object* x_4, lean_object* x_5) {
+_start:
+{
+lean_object* x_6; lean_object* x_7; lean_object* x_8; lean_object* x_9; lean_object* x_10; lean_object* x_11; lean_object* x_12; lean_object* x_13; lean_object* x_14; lean_object* x_15; lean_object* x_16; lean_object* x_17; lean_object* x_18; 
+x_6 = l_panicWithPos___rarg___closed__1;
+x_7 = lean_string_append(x_6, x_2);
+x_8 = l_panicWithPos___rarg___closed__2;
+x_9 = lean_string_append(x_7, x_8);
+x_10 = l_Nat_repr(x_3);
+x_11 = lean_string_append(x_9, x_10);
+lean_dec(x_10);
+x_12 = lean_string_append(x_11, x_8);
+x_13 = l_Nat_repr(x_4);
+x_14 = lean_string_append(x_12, x_13);
+lean_dec(x_13);
+x_15 = l_panicWithPos___rarg___closed__3;
+x_16 = lean_string_append(x_14, x_15);
+x_17 = lean_string_append(x_16, x_5);
+x_18 = lean_panic_fn(x_17);
+return x_18;
+}
+}
+lean_object* l_panicWithPos(lean_object* x_1) {
+_start:
+{
+lean_object* x_2; 
+x_2 = lean_alloc_closure((void*)(l_panicWithPos___rarg___boxed), 5, 0);
+return x_2;
+}
+}
+lean_object* l_panicWithPos___rarg___boxed(lean_object* x_1, lean_object* x_2, lean_object* x_3, lean_object* x_4, lean_object* x_5) {
+_start:
+{
+lean_object* x_6; 
+x_6 = l_panicWithPos___rarg(x_1, x_2, x_3, x_4, x_5);
+lean_dec(x_5);
+lean_dec(x_2);
+return x_6;
+}
+}
 lean_object* initialize_init_data_string_basic(lean_object*);
+lean_object* initialize_init_data_tostring(lean_object*);
 static bool _G_initialized = false;
 lean_object* initialize_init_util(lean_object* w) {
 if (_G_initialized) return w;
@@ -63,6 +146,14 @@ _G_initialized = true;
 if (lean_io_result_is_error(w)) return w;
 w = initialize_init_data_string_basic(w);
 if (lean_io_result_is_error(w)) return w;
+w = initialize_init_data_tostring(w);
+if (lean_io_result_is_error(w)) return w;
+l_panicWithPos___rarg___closed__1 = _init_l_panicWithPos___rarg___closed__1();
+lean_mark_persistent(l_panicWithPos___rarg___closed__1);
+l_panicWithPos___rarg___closed__2 = _init_l_panicWithPos___rarg___closed__2();
+lean_mark_persistent(l_panicWithPos___rarg___closed__2);
+l_panicWithPos___rarg___closed__3 = _init_l_panicWithPos___rarg___closed__3();
+lean_mark_persistent(l_panicWithPos___rarg___closed__3);
 return w;
 }
 #ifdef __cplusplus