diff --git a/src/core/json/include/sourcemeta/core/json_object.h b/src/core/json/include/sourcemeta/core/json_object.h
index fee9b7249..5c88c42f2 100644
--- a/src/core/json/include/sourcemeta/core/json_object.h
+++ b/src/core/json/include/sourcemeta/core/json_object.h
@@ -393,8 +393,8 @@ template <typename Key, typename Value, typename Hash> class JSONObject {
   inline auto size() const -> std::size_t { return this->data.size(); }
 
   /// Access an object entry by its underlying positional index
-  inline auto at(const size_type index) const noexcept
-      -> const Container::Entry & {
+  inline auto at(const size_type index) const noexcept -> const
+      typename Container::Entry & {
     return this->data.at(index);
   }