diff --git a/core/my_basic.c b/core/my_basic.c
index a6a7072..cf3412d 100644
--- a/core/my_basic.c
+++ b/core/my_basic.c
@@ -3664,7 +3664,8 @@ int mb_pop_value(mb_interpreter_t* s, void** l, mb_value_t* val) {
 
 	running = (_running_context_t*)(s->running_context);
 
-	inep = (int*)_ls_back(running->in_neg_expr)->data;
+	if(!_ls_empty(running->in_neg_expr))
+		inep = (int*)_ls_back(running->in_neg_expr)->data;
 
 	val_ptr = &val_obj;
 	memset(val_ptr, 0, sizeof(_object_t));
@@ -3681,7 +3682,7 @@ int mb_pop_value(mb_interpreter_t* s, void** l, mb_value_t* val) {
 		_ls_pushback(running->temp_values, val_ptr);
 	}
 
-	if(running->no_eat_comma_mark < _NO_EAT_COMMA && !(*inep)) {
+	if(running->no_eat_comma_mark < _NO_EAT_COMMA && (inep && !(*inep))) {
 		if(ast && ((_object_t*)(ast->data))->type == _DT_SEP && ((_object_t*)(ast->data))->data.separator == ',') {
 			ast = ast->next;
 		}