diff --git a/src/util/_impl/_dedup_impl.scad b/src/util/_impl/_dedup_impl.scad
index 6ba75dea..438204f9 100644
--- a/src/util/_impl/_dedup_impl.scad
+++ b/src/util/_impl/_dedup_impl.scad
@@ -6,7 +6,7 @@ function _dedup(elems, leng, buckets, eq, hash, bucket_numbers) =
         n_buckets_lt = [
         for(i = 0, n_buckets = _dedup_add(buckets, [i, elems[i]], eq, hash, bucket_numbers), is_continue = i < end;
             is_continue; 
-            i = i + 1, is_continue = i < end, n_buckets = is_continue ? _dedup_add(n_buckets, [i, elems[i]], eq, hash, bucket_numbers) : n_buckets) 
+            i = i + 1, is_continue = i < end, n_buckets = is_continue ? _dedup_add(n_buckets, [i, elems[i]], eq, hash, bucket_numbers) : undef) 
             n_buckets
         ]
     )
diff --git a/src/util/map/_impl/_hashmap_impl.scad b/src/util/map/_impl/_hashmap_impl.scad
index 59776f9b..de9babd7 100644
--- a/src/util/map/_impl/_hashmap_impl.scad
+++ b/src/util/map/_impl/_hashmap_impl.scad
@@ -6,7 +6,7 @@ function _hashmap(kv_lt, leng, buckets, b_numbers, eq, hash) =
         n_buckets_lt = [
         for(i = 0, n_buckets = _hashmap_put(buckets, b_numbers, kv_lt[i][0], kv_lt[i][1], eq, hash), is_continue = i < end;
             is_continue; 
-            i = i + 1, is_continue = i < end, n_buckets = is_continue ? _hashmap_put(n_buckets, b_numbers, kv_lt[i][0], kv_lt[i][1], eq, hash) : n_buckets) 
+            i = i + 1, is_continue = i < end, n_buckets = is_continue ? _hashmap_put(n_buckets, b_numbers, kv_lt[i][0], kv_lt[i][1], eq, hash) : undef) 
             n_buckets
         ]
     )
diff --git a/src/util/set/_impl/_hashset_impl.scad b/src/util/set/_impl/_hashset_impl.scad
index c9958ae5..439b82e1 100644
--- a/src/util/set/_impl/_hashset_impl.scad
+++ b/src/util/set/_impl/_hashset_impl.scad
@@ -6,7 +6,7 @@ function _hashset(lt, leng, buckets, b_numbers, eq, hash) =
         n_buckets_lt = [
         for(i = 0, n_buckets = _hashset_add(buckets, b_numbers, lt[i], eq, hash), is_continue = i < end;
             is_continue; 
-            i = i + 1, is_continue = i < end, n_buckets = is_continue ? _hashset_add(n_buckets, b_numbers, lt[i], eq, hash) : n_buckets) 
+            i = i + 1, is_continue = i < end, n_buckets = is_continue ? _hashset_add(n_buckets, b_numbers, lt[i], eq, hash) : undef) 
             n_buckets
         ]
     )