diff --git a/src/runtime/subtree.h b/src/runtime/subtree.h
index ec8e3032..0fd3311a 100644
--- a/src/runtime/subtree.h
+++ b/src/runtime/subtree.h
@@ -35,7 +35,6 @@ struct Subtree {
   uint32_t error_cost;
   uint32_t node_count;
   uint32_t repeat_depth;
-  uint32_t child_count;
   int32_t dynamic_precedence;
 
   bool visible : 1;
diff --git a/test/runtime/subtree_test.cc b/test/runtime/subtree_test.cc
index 246f985e..1ff7356f 100644
--- a/test/runtime/subtree_test.cc
+++ b/test/runtime/subtree_test.cc
@@ -5,7 +5,7 @@
 #include "runtime/length.h"
 
 void assert_consistent(const Subtree *tree) {
-  if (tree->child_count == 0) return;
+  if (tree->children.size == 0) return;
   AssertThat(tree->children.contents[0]->padding, Equals<Length>(tree->padding));
 
   Length total_children_size = length_zero();