fix the problem, add another test

Author: wyattscarpenter

mypy/errors.py

@@ -806,8 +806,8 @@ def generate_unused_ignore_errors(self, file: str) -> None:
                 continue
             if codes.UNUSED_IGNORE.code in ignored_codes:
                 continue
-            used_ignored_codes = used_ignored_lines[line]
-            unused_ignored_codes = set(ignored_codes) - set(used_ignored_codes)
+            used_ignored_codes = set(used_ignored_lines[line])
+            unused_ignored_codes = [c for c in ignored_codes if c not in used_ignored_codes]
             # `ignore` is used
             if not ignored_codes and used_ignored_codes:
                 continue
@@ -817,7 +817,7 @@ def generate_unused_ignore_errors(self, file: str) -> None:
             # Display detail only when `ignore[...]` specifies more than one error code
             unused_codes_message = ""
             if len(ignored_codes) > 1 and unused_ignored_codes:
-                unused_codes_message = f"[{', '.join(sorted(unused_ignored_codes))}]"
+                unused_codes_message = f"[{', '.join(unused_ignored_codes)}]"
             message = f'Unused "type: ignore{unused_codes_message}" comment'
             for unused in unused_ignored_codes:
                 narrower = set(used_ignored_codes) & codes.sub_code_map[unused]

test-data/unit/check-ignore.test

@@ -282,6 +282,8 @@ class CD(six.with_metaclass(M)):  # E: Multiple metaclass definitions
 5 # type: ignore[steven, import] # E: Unused "type: ignore[steven, import]" comment
 -- Spacing is not preserved
 5 # type: ignore[  steven,      import ] # E: Unused "type: ignore[steven, import]" comment
+-- Make sure it works as intended in more complex situations
+1 + "ok" + "ok".foo # type: ignore[  operator,steven,attr-defined, import] # E: Unused "type: ignore[steven, import]" comment
 
 [case testUnusedIgnoreTryExcept]
 # flags: --warn-unused-ignores