diff -r ff72bd52d56a -r 9d2b2df2c2ba hgext/fastannotate/commands.py
--- a/hgext/fastannotate/commands.py	Fri Mar 06 10:52:44 2020 +0100
+++ b/hgext/fastannotate/commands.py	Fri Mar 06 13:27:41 2020 -0500
@@ -233,7 +233,7 @@
                         showlines=(showlines and not showdeleted),
                     )
                     if showdeleted:
-                        existinglines = set((l[0], l[1]) for l in result)
+                        existinglines = {(l[0], l[1]) for l in result}
                         result = a.annotatealllines(
                             rev, showpath=showpath, showlines=showlines
                         )