--- a/hgext/rebase.py	Thu Dec 12 23:11:33 2019 -0800
+++ b/hgext/rebase.py	Thu Dec 12 22:43:15 2019 -0800
@@ -1025,6 +1025,7 @@
             opts, action, b'confirm', b'dry_run'
         )
     cmdutil.check_at_most_one_arg(opts, b'confirm', b'dry_run')
+    cmdutil.check_at_most_one_arg(opts, b'rev', b'source', b'base')
 
     if action or repo.currenttransaction() is not None:
         # in-memory rebase is not compatible with resuming rebases.
@@ -1259,12 +1260,6 @@
 
     # destspace is here to work around issues with `hg pull --rebase` see
     # issue5214 for details
-    if srcf and basef:
-        raise error.Abort(_(b'cannot specify both a source and a base'))
-    if revf and basef:
-        raise error.Abort(_(b'cannot specify both a revision and a base'))
-    if revf and srcf:
-        raise error.Abort(_(b'cannot specify both a revision and a source'))
 
     cmdutil.checkunfinished(repo)
     if not inmemory:

--- a/tests/test-rebase-parameters.t	Thu Dec 12 23:11:33 2019 -0800
+++ b/tests/test-rebase-parameters.t	Thu Dec 12 22:43:15 2019 -0800
@@ -73,14 +73,14 @@
   [255]
 
   $ hg rebase --base 5 --source 4
-  abort: cannot specify both a source and a base
+  abort: cannot specify both --source and --base
   [255]
 
   $ hg rebase --rev 5 --source 4
-  abort: cannot specify both a revision and a source
+  abort: cannot specify both --rev and --source
   [255]
   $ hg rebase --base 5 --rev 4
-  abort: cannot specify both a revision and a base
+  abort: cannot specify both --rev and --base
   [255]
 
   $ hg rebase --base 6