diff --git a/src/stim/util_top/reference_sample_tree.cc b/src/stim/util_top/reference_sample_tree.cc
index c6c0f455..bb8764aa 100644
--- a/src/stim/util_top/reference_sample_tree.cc
+++ b/src/stim/util_top/reference_sample_tree.cc
@@ -130,7 +130,7 @@ ReferenceSampleTree ReferenceSampleTree::simplified() const {
     if (flat.empty()) {
         return ReferenceSampleTree();
     } else if (flat.size() == 1) {
-        return flat[0];
+        return std::move(flat[0]);
     }
 
     ReferenceSampleTree result;
diff --git a/src/stim/util_top/reference_sample_tree.inl b/src/stim/util_top/reference_sample_tree.inl
index 68ff0824..746920dc 100644
--- a/src/stim/util_top/reference_sample_tree.inl
+++ b/src/stim/util_top/reference_sample_tree.inl
@@ -72,7 +72,7 @@ ReferenceSampleTree CompressedReferenceSampleHelper<W>::do_loop_with_tortoise_ha
     }
 
     if (hare_steps == reps) {
-        // No loop found.
+        // No periodic state found before reaching the end of the loop.
         sim = std::move(hare.sim);
         return result;
     }