diff --git a/mypy/messages.py b/mypy/messages.py
index 0f3a5be368a4..83af360821b7 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -2678,7 +2678,14 @@ def format_list(types: Sequence[Type]) -> str:
         return ", ".join(format(typ) for typ in types)
 
     def format_union_items(types: Sequence[Type]) -> list[str]:
-        formatted = [format(typ) for typ in types if format(typ) != "None"]
+        formatted = []
+        has_none = False
+        for typ in types:
+            item = format(typ)
+            if item == "None":
+                has_none = True
+            else:
+                formatted.append(item)
         if len(formatted) > MAX_UNION_ITEMS and verbosity == 0:
             more = len(formatted) - MAX_UNION_ITEMS // 2
             formatted = formatted[: MAX_UNION_ITEMS // 2]
@@ -2686,7 +2693,7 @@ def format_union_items(types: Sequence[Type]) -> list[str]:
             more = 0
         if more:
             formatted.append(f"<{more} more items>")
-        if any(format(typ) == "None" for typ in types):
+        if has_none:
             formatted.append("None")
         return formatted