1 files changed, 2 insertions, 2 deletions
diff --git a/src/google/protobuf/repeated_field.h b/src/google/protobuf/repeated_field.h
index 50051831..df0625c9 100644
--- a/src/google/protobuf/repeated_field.h
+++ b/src/google/protobuf/repeated_field.h
@@ -1307,11 +1307,11 @@ class RepeatedPtrIterator
     it_ += d;
     return *this;
   }
-  friend iterator operator+(iterator it, difference_type d) {
+  friend iterator operator+(iterator it, const difference_type d) {
     it += d;
     return it;
   }
-  friend iterator operator+(difference_type d, iterator it) {
+  friend iterator operator+(const difference_type d, iterator it) {
     it += d;
     return it;
   }