diff --git a/eden/scm/edenscm/mercurial/revset.py b/eden/scm/edenscm/mercurial/revset.py
index febd799ba6..acd8779791 100644
--- a/eden/scm/edenscm/mercurial/revset.py
+++ b/eden/scm/edenscm/mercurial/revset.py
@@ -576,9 +576,9 @@ def ancestorspec(repo, subset, x, n, order):
     nullrev = node.nullrev
     for r in s:
         if r != nullrev:
-            n = firstancestornth(tonode(r), n)
-            if n is not None:
-                psadd(torev(n))
+            ancestor = firstancestornth(tonode(r), n)
+            if ancestor is not None:
+                psadd(torev(ancestor))
     return subset & baseset(ps, repo=repo)
 
 
diff --git a/eden/scm/tests/test-revset-t.py b/eden/scm/tests/test-revset-t.py
index 6a917344cb..7784f2af24 100644
--- a/eden/scm/tests/test-revset-t.py
+++ b/eden/scm/tests/test-revset-t.py
@@ -2680,3 +2680,9 @@ sh % "hg log -r '\n. +\n.^ +'" == r"""
     ( . + .^ +
               ^ here)
     [255]"""
+
+# test ancestorspec with multiple base revisions
+
+sh % "log '(. + .^)~1'" == r"""
+    4
+    8"""