diff --git a/lib/ansible/plugins/action/copy.py b/lib/ansible/plugins/action/copy.py
index 200e02b6678..dc7893e2c18 100644
--- a/lib/ansible/plugins/action/copy.py
+++ b/lib/ansible/plugins/action/copy.py
@@ -199,15 +199,6 @@ def _walk_dirs(topdir, base_path=None, local_follow=False, trailing_slash_detect
     return r_files
 
 
-def combine_result_diffs(dest, source):
-    if not source.get("diff", None):
-        return
-    if isinstance(source["diff"], list):
-        dest["diff"] += source["diff"]
-    else:
-        dest["diff"].append(source["diff"])
-
-
 class ActionModule(ActionBase):
 
     TRANSFERS_FILES = True