mercurial/copies.py

--- a/mercurial/copies.py	Wed Apr 17 23:10:14 2019 -0700
+++ b/mercurial/copies.py	Thu Apr 18 00:05:05 2019 -0700
@@ -134,10 +134,6 @@
             if t[v] != k:
                 # file wasn't renamed back to itself (i.e. case 4, not 3)
                 t[k] = t[v]
-            if v not in dst:
-                # chain was a rename, not a copy
-                # this deletes the copy for 'y' in case 4
-                del t[v]
         if v in src:
             # file is a copy of an existing file, i.e. case 6.
             t[k] = v