diff --git a/mercurial/templatefilters.py b/mercurial/templatefilters.py
--- a/mercurial/templatefilters.py
+++ b/mercurial/templatefilters.py
@@ -106,12 +106,17 @@ def basename(path):
     return os.path.basename(path)
 
 
+def _tocborencodable(obj):
+    if isinstance(obj, smartset.abstractsmartset):
+        return list(obj)
+    return obj
+
+
 @templatefilter(b'cbor')
 def cbor(obj):
     """Any object. Serializes the object to CBOR bytes."""
-    if isinstance(obj, smartset.abstractsmartset):
-        # cborutil is stricter about type than json() filter
-        obj = list(obj)
+    # cborutil is stricter about type than json() filter
+    obj = pycompat.rapply(_tocborencodable, obj)
     return b''.join(cborutil.streamencode(obj))
 
 
diff --git a/tests/test-template-functions.t b/tests/test-template-functions.t
--- a/tests/test-template-functions.t
+++ b/tests/test-template-functions.t
@@ -1616,6 +1616,15 @@ Test cbor filter:
    ]
   ]
 
+  $ hg log -T "{dict(foo=revset('.'))|cbor}" -R a -l1 | "$PYTHON" "$TESTTMP/decodecbor.py"
+  [
+   {
+    'foo': [
+     10
+    ]
+   }
+  ]
+
 json filter should escape HTML tags so that the output can be embedded in hgweb:
 
   $ hg log -T "{'<foo@example.org>'|json}\n" -R a -l1