diff --git a/src/caosdb/transaction.cpp b/src/caosdb/transaction.cpp
index 9150dca5e87daa6954ee4c3793fc60f023bd34af..9709a884aa8e2e2a9b9481f08d0ccba9b8feef74 100644
--- a/src/caosdb/transaction.cpp
+++ b/src/caosdb/transaction.cpp
@@ -104,7 +104,10 @@ ResultSet::iterator::iterator(const ResultSet *result_set_param, size_t index)
   : current_index(index), result_set(result_set_param) {}
 
 auto ResultSet::iterator::operator*() const -> const Entity & {
-  return this->result_set->At(current_index);
+  // TODO(tf) clang warns about a bugprone conversion from unsigned
+  // size_t to signed int, i.e., the `index` of ResultSet::At. Should
+  // we make this unsigned as well?
+  return this->result_set->At(current_index); // NOLINT
 }
 
 auto ResultSet::iterator::operator++() -> ResultSet::iterator & {