diff --git a/mercurial/revset.py b/mercurial/revset.py
--- a/mercurial/revset.py
+++ b/mercurial/revset.py
@@ -572,7 +572,7 @@ def children(repo, subset, x):
     """``children(set)``
     Child changesets of changesets in set.
     """
-    s = getset(repo, baseset(repo), x)
+    s = getset(repo, fullreposet(repo), x)
     cs = _children(repo, subset, s)
     return subset & cs