diff --git a/src/ant.c b/src/ant.c
index d631ea8..21aa1a9 100644
--- a/src/ant.c
+++ b/src/ant.c
@@ -5024,7 +5024,7 @@ static ant_value_t iter_close_iterator(ant_t *js, ant_value_t iterator) {
   ant_offset_t return_off = lkp_proto(js, iterator, "return", 6);
   if (return_off == 0) return js_mkundef();
   ant_value_t return_method = propref_load(js, return_off);
-  if (vtype(return_method) != T_FUNC && vtype(return_method) != T_CFUNC) {
+  if (!is_callable(return_method)) {
     return js_mkerr(js, "iterator.return is not a function");
   }
   return iter_call_noargs_with_this(js, iterator, return_method);
@@ -5046,7 +5046,7 @@ static ant_value_t iter_foreach(ant_t *js, ant_value_t iterable, iter_callback_t
     if (next_off == 0) { return js_mkerr(js, "iterator.next is not a function"); }
     
     ant_value_t next_method = propref_load(js, next_off);
-    if (vtype(next_method) != T_FUNC && vtype(next_method) != T_CFUNC) {
+    if (!is_callable(next_method)) {
       return js_mkerr(js, "iterator.next is not a function");
     }
     
diff --git a/src/modules/symbol.c b/src/modules/symbol.c
index 0870cda..654f67b 100644
--- a/src/modules/symbol.c
+++ b/src/modules/symbol.c
@@ -266,7 +266,7 @@ ant_value_t maybe_call_symbol_method(
 
   uint8_t mt = vtype(method);
   if (mt == T_UNDEF || mt == T_NULL) return js_mkundef();
-  if (mt != T_FUNC && mt != T_CFUNC) {
+  if (!is_callable(method)) {
     return js_mkerr_typed(js, JS_ERR_TYPE, "Symbol method is not callable");
   }
 
diff --git a/src/silver/glue.c b/src/silver/glue.c
index 1d6ac79..fb79248 100644
--- a/src/silver/glue.c
+++ b/src/silver/glue.c
@@ -344,8 +344,7 @@ static ant_value_t jit_iter_advance_from_buf(
     ant_value_t next_method = iter_buf[1];
     GC_ROOT_PIN(js, iterator);
     GC_ROOT_PIN(js, next_method);
-    uint8_t ft = vtype(next_method);
-    if (ft != T_FUNC && ft != T_CFUNC) {
+    if (!is_callable(next_method)) {
       GC_ROOT_RESTORE(js, root_mark);
       return js_mkerr(js, "iterator.next is not a function");
     }
@@ -388,8 +387,7 @@ void jit_helper_destructure_close(
     GC_ROOT_PIN(js, iterator);
     ant_value_t return_fn = js_getprop_fallback(js, iterator, "return");
     GC_ROOT_PIN(js, return_fn);
-    uint8_t ft = vtype(return_fn);
-    if (ft == T_FUNC || ft == T_CFUNC)
+    if (is_callable(return_fn))
       sv_vm_call(vm, js, return_fn, iterator, NULL, 0, NULL, false);
   }
 
@@ -429,8 +427,7 @@ ant_value_t jit_helper_for_of(
 
   ant_value_t iter_fn = js_get_sym(js, iterable, get_iterator_sym());
   GC_ROOT_PIN(js, iter_fn);
-  uint8_t ft = vtype(iter_fn);
-  if (ft != T_FUNC && ft != T_CFUNC) {
+  if (!is_callable(iter_fn)) {
     GC_ROOT_RESTORE(js, root_mark);
     return js_mkerr(js, "not iterable");
   }
diff --git a/src/silver/ops/iteration.h b/src/silver/ops/iteration.h
index d221368..d9ab44e 100644
--- a/src/silver/ops/iteration.h
+++ b/src/silver/ops/iteration.h
@@ -261,8 +261,7 @@ static inline ant_value_t sv_iter_advance(
   default: {
     ant_value_t next_method = vm->stack[vm->sp - 2];
     ant_value_t iterator = vm->stack[vm->sp - 3];
-    uint8_t ft = vtype(next_method);
-    if (ft != T_FUNC && ft != T_CFUNC)
+    if (!is_callable(next_method))
       return js_mkerr(js, "iterator.next is not a function");
     ant_value_t result = sv_vm_call(vm, js, next_method, iterator, NULL, 0, NULL, false);
     if (is_err(result)) return result;
@@ -304,8 +303,7 @@ static inline void sv_op_iter_close(sv_vm_t *vm, ant_t *js) {
   if (tag == SV_ITER_GENERIC) {
     ant_value_t iterator = vm->stack[vm->sp - 3];
     ant_value_t return_fn = js_getprop_fallback(js, iterator, "return");
-    uint8_t ft = vtype(return_fn);
-    if (ft == T_FUNC || ft == T_CFUNC)
+    if (is_callable(return_fn))
       sv_vm_call(vm, js, return_fn, iterator, NULL, 0, NULL, false);
   }
   vm->sp -= 3;
@@ -347,8 +345,7 @@ static inline ant_value_t sv_op_destructure_rest(sv_vm_t *vm, ant_t *js) {
 static inline ant_value_t sv_op_iter_call(sv_vm_t *vm, ant_t *js, uint8_t *ip) {
   ant_value_t method = vm->stack[vm->sp - 1];
   ant_value_t iterator = vm->stack[vm->sp - 4];
-  uint8_t ft = vtype(method);
-  if (ft != T_FUNC && ft != T_CFUNC)
+  if (!is_callable(method))
     return js_mkerr(js, "iterator method is not callable");
   ant_value_t result = sv_vm_call(vm, js, method, iterator, NULL, 0, NULL, false);
   if (is_err(result)) return result;
@@ -364,8 +361,7 @@ static inline sv_await_result_t sv_op_await_iter_next(sv_vm_t *vm, ant_t *js) {
   };
   ant_value_t next_method = vm->stack[vm->sp - 2];
   ant_value_t iterator = vm->stack[vm->sp - 3];
-  uint8_t ft = vtype(next_method);
-  if (ft != T_FUNC && ft != T_CFUNC)
+  if (!is_callable(next_method))
     return (sv_await_result_t){ .state = SV_AWAIT_ERROR, .value = js_mkerr(js, "iterator.next is not a function"), .handoff = false };
   ant_value_t result = sv_vm_call(vm, js, next_method, iterator, NULL, 0, NULL, false);
   if (is_err(result))