diff --git a/compiler/utils/array_ref.h b/compiler/utils/array_ref.h
index b1b0ee5..ff5a77c 100644
--- a/compiler/utils/array_ref.h
+++ b/compiler/utils/array_ref.h
@@ -89,6 +89,8 @@
       : array_(v.data()), size_(v.size()) {
   }
 
+  ArrayRef(const ArrayRef&) = default;
+
   // Assignment operators.
 
   ArrayRef& operator=(const ArrayRef& other) {