diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 833d8d4d2..b7fcc466a 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -1255,6 +1255,8 @@ class basic_json
         {
             return j.m_parent == this;
         }));
+#else
+        static_cast<void>(check_parents);
 #endif
     }
 
@@ -3611,7 +3613,7 @@ class basic_json
 
 #if JSON_DIAGNOSTICS
                 // set parent for values added above
-                set_parents(begin() + previous_size, idx + 1 - previous_size);
+                set_parents(begin() + static_cast<typename iterator::difference_type>(previous_size), static_cast<typename iterator::difference_type>(idx + 1 - previous_size));
 #endif
             }
 
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 5f23622f5..8d55debbf 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -18038,6 +18038,8 @@ class basic_json
         {
             return j.m_parent == this;
         }));
+#else
+        static_cast<void>(check_parents);
 #endif
     }
 
@@ -20394,7 +20396,7 @@ class basic_json
 
 #if JSON_DIAGNOSTICS
                 // set parent for values added above
-                set_parents(begin() + previous_size, idx + 1 - previous_size);
+                set_parents(begin() + static_cast<typename iterator::difference_type>(previous_size), static_cast<typename iterator::difference_type>(idx + 1 - previous_size));
 #endif
             }