diff --git a/lib/error.c b/lib/error.c
index 65eabc06..ee8e9e95 100644
--- a/lib/error.c
+++ b/lib/error.c
@@ -39,8 +39,6 @@ pic_prepare_try(pic_state *pic)
 {
   struct context *cxt = pic_alloca(pic, sizeof(struct context));
 
-  cxt->ai = pic->cxt->ai;
-  pic->cxt->ai--;               /* cxt should be freed after this try ends */
   cxt->pc = NULL;
   cxt->fp = NULL;
   cxt->sp = NULL;
diff --git a/lib/ext/file.c b/lib/ext/file.c
index 689bd950..4efc9422 100644
--- a/lib/ext/file.c
+++ b/lib/ext/file.c
@@ -5,6 +5,7 @@
 #include <stdio.h>
 
 #include "picrin.h"
+#include "../object.h"
 
 #if PIC_USE_FILE
 
diff --git a/lib/gc.c b/lib/gc.c
index 1b9ebf2b..2b4e1c70 100644
--- a/lib/gc.c
+++ b/lib/gc.c
@@ -144,11 +144,11 @@ pic_free(pic_state *pic, void *ptr)
 static void
 gc_protect(pic_state *pic, struct object *obj)
 {
-  if (pic->cxt->ai >= pic->arena_size) {
+  if (pic->ai >= pic->arena_size) {
     pic->arena_size = pic->arena_size * 2 + 1;
     pic->arena = pic_realloc(pic, pic->arena, sizeof(struct object *) * pic->arena_size);
   }
-  pic->arena[pic->cxt->ai++] = obj;
+  pic->arena[pic->ai++] = obj;
 }
 
 pic_value
@@ -165,13 +165,13 @@ pic_protect(pic_state *pic, pic_value v)
 size_t
 pic_enter(pic_state *pic)
 {
-  return pic->cxt->ai;
+  return pic->ai;
 }
 
 void
 pic_leave(pic_state *pic, size_t state)
 {
-  pic->cxt->ai = state;
+  pic->ai = state;
 }
 
 void *
@@ -332,7 +332,7 @@ gc_mark_phase(pic_state *pic)
   }
 
   /* arena */
-  for (j = 0; j < pic->cxt->ai; ++j) {
+  for (j = 0; j < pic->ai; ++j) {
     gc_mark_object(pic, (struct object *)pic->arena[j]);
   }
 
diff --git a/lib/include/picrin.h b/lib/include/picrin.h
index 0426c186..664050af 100644
--- a/lib/include/picrin.h
+++ b/lib/include/picrin.h
@@ -297,13 +297,14 @@ pic_value pic_raise_continuable(pic_state *pic, pic_value err);
 PIC_NORETURN void pic_raise(pic_state *, pic_value v);
 PIC_NORETURN void pic_error(pic_state *, const char *msg, int n, ...);
 
-#define pic_try pic_try_(PIC_GENSYM(cont), PIC_GENSYM(jmp))
-#define pic_try_(cont, jmp)                                             \
+#define pic_try pic_try_(PIC_GENSYM(jmp))
+#define pic_try_(jmp)                                                   \
   do {                                                                  \
     extern PIC_JMPBUF *pic_prepare_try(pic_state *);                    \
     extern void pic_enter_try(pic_state *);                             \
     extern void pic_exit_try(pic_state *);                              \
     extern pic_value pic_abort_try(pic_state *);                        \
+    size_t pic_try_ai_ = pic_enter(pic);                                \
     PIC_JMPBUF *jmp = pic_prepare_try(pic);                             \
     if (PIC_SETJMP(*jmp) == 0) {                                        \
       pic_enter_try(pic);
@@ -312,6 +313,8 @@ PIC_NORETURN void pic_error(pic_state *, const char *msg, int n, ...);
       pic_exit_try(pic);                                  \
     } else {                                              \
       e = pic_abort_try(pic);                             \
+      pic_leave(pic, pic_try_ai_);                        \
+      pic_protect(pic, e);                                \
       goto label;                                         \
     }                                                     \
   } while (0);                                            \
diff --git a/lib/proc.c b/lib/proc.c
index 10771a05..019153fd 100644
--- a/lib/proc.c
+++ b/lib/proc.c
@@ -360,7 +360,7 @@ pic_value
 pic_apply(pic_state *pic, pic_value proc, int argc, pic_value *argv)
 {
   struct context cxt;
-  size_t arena_base = pic->cxt->ai;
+  size_t arena_base = pic->ai;
 
 #define MKCALL(argc) (cxt.tmpcode[0] = OP_CALL, cxt.tmpcode[1] = (argc), cxt.tmpcode)
 
@@ -376,15 +376,14 @@ pic_apply(pic_state *pic, pic_value proc, int argc, pic_value *argv)
   }
   cxt.fp = NULL;
   cxt.irep = NULL;
-  cxt.ai = pic->cxt->ai;
   cxt.prev = pic->cxt;
   pic->cxt = &cxt;
 
-  if (PIC_SETJMP(cxt.jmp) != 0) {
-    /* pass */
-  }
+#define SAVE (pic->ai = arena_base)
 
-#define SAVE (cxt.ai = arena_base)
+  if (PIC_SETJMP(cxt.jmp) != 0) {
+    SAVE;
+  }
 
 #define A (cxt.pc[1])
 #define B (cxt.pc[2])
diff --git a/lib/state.c b/lib/state.c
index 7534c54c..808ec504 100644
--- a/lib/state.c
+++ b/lib/state.c
@@ -171,7 +171,6 @@ pic_open(pic_allocf allocf, void *userdata)
   pic->userdata = userdata;
 
   /* context */
-  pic->default_cxt.ai = 0;
   pic->default_cxt.pc = NULL;
   pic->default_cxt.fp = NULL;
   pic->default_cxt.sp = NULL;
@@ -182,6 +181,7 @@ pic_open(pic_allocf allocf, void *userdata)
   /* arena */
   pic->arena = allocf(userdata, NULL, PIC_ARENA_SIZE * sizeof(struct object *));
   pic->arena_size = PIC_ARENA_SIZE;
+  pic->ai = 0;
 
   if (! pic->arena) {
     goto EXIT_ARENA;
@@ -250,7 +250,7 @@ pic_close(pic_state *pic)
 
   /* clear out root objects */
   pic->cxt = &pic->default_cxt;
-  pic->cxt->ai = 0;
+  pic->ai = 0;
   pic->halt = pic_invalid_value(pic);
   pic->globals = pic_invalid_value(pic);
   pic->features = pic_invalid_value(pic);
diff --git a/lib/state.h b/lib/state.h
index c96b3f39..60fd9907 100644
--- a/lib/state.h
+++ b/lib/state.h
@@ -16,7 +16,6 @@ KHASH_DECLARE(oblist, struct string *, struct symbol *)
 
 struct context {
   PIC_JMPBUF jmp;
-  size_t ai;
 
   /* vm */
   const code_t *pc;
@@ -35,6 +34,7 @@ struct pic_state {
 
   struct context *cxt, default_cxt;
 
+  size_t ai;
   pic_value dyn_env;
 
   pic_value features;           /* list of symbols */