diff --git a/src/runtime/reusable_node.h b/src/runtime/reusable_node.h
index 803304de..71d56b68 100644
--- a/src/runtime/reusable_node.h
+++ b/src/runtime/reusable_node.h
@@ -25,11 +25,15 @@ static inline void reusable_node_reset(ReusableNode *self, Tree *tree) {
 }
 
 static inline Tree *reusable_node_tree(ReusableNode *self) {
-  return array_back(&self->stack)->tree;
+  return self->stack.size > 0
+    ? self->stack.contents[self->stack.size - 1].tree
+    : NULL;
 }
 
 static inline uint32_t reusable_node_byte_offset(ReusableNode *self) {
-  return array_back(&self->stack)->byte_offset;
+  return self->stack.size > 0
+    ? self->stack.contents[self->stack.size - 1].byte_offset
+    : UINT32_MAX;
 }
 
 static inline void reusable_node_delete(ReusableNode *self) {
@@ -52,6 +56,7 @@ static inline void reusable_node_advance(ReusableNode *self) {
   do {
     StackEntry popped_entry = array_pop(&self->stack);
     next_index = popped_entry.child_index + 1;
+    if (self->stack.size == 0) return;
     tree = array_back(&self->stack)->tree;
   } while (tree->children.size <= next_index);