diff --git a/src/json.hpp b/src/json.hpp
index d8bc7bdf4..9754e464c 100644
--- a/src/json.hpp
+++ b/src/json.hpp
@@ -553,7 +553,7 @@ inline bool operator<(const value_t lhs, const value_t rhs) noexcept
 
     const auto l_index = static_cast<std::size_t>(lhs);
     const auto r_index = static_cast<std::size_t>(rhs);
-    return (l_index < order.size() and r_index <= order.size() and order[l_index] < order[r_index]);
+    return (l_index < order.size() and r_index < order.size() and order[l_index] < order[r_index]);
 }