Address review: drop changelog entry, remove comment

Signed-off-by: gopoto <[email protected]>

Author: codex-maintainers

CHANGELOG.md

@@ -45,14 +45,6 @@ class A:
 
 Contributed by Marc Mueller (PR [18641](https://github.com/python/mypy/pull/18641))
 
-### Other Notable Fixes and Improvements
-
-*   Pattern matching on discriminant attributes and keys in union types
-    (such as `tag` fields in `TypedDict`s or classes) now correctly narrows
-    the subject type within each `case` block. Previously, mypy would fail
-    to narrow the parent type when matching on expressions like `match d["tag"]`
-    or `match d.tag`. This fixes issue [#16286](https://github.com/python/mypy/issues/16286).
-
 ## Mypy 1.15
 
 We’ve just uploaded mypy 1.15 to the Python Package Index ([PyPI](https://pypi.org/project/mypy/)).

mypy/checker.py

@@ -5527,12 +5527,6 @@ def visit_match_stmt(self, s: MatchStmt) -> None:
                         pattern_map, else_map = conditional_types_to_typemaps(
                             named_subject, pattern_type.type, pattern_type.rest_type
                         )
-                        # Also refine the parent expression of the subject.
-                        # For example, if the subject is an index or attribute expression like
-                        # ``d["key"]`` or ``d.attr``, propagate any narrowing information about
-                        # the subject back up to ``d`` (and recursively, to further parents).
-                        # This mirrors the behavior of our conditional (``if``) binder,
-                        # which calls ``propagate_up_typemap_info`` when handling comparisons.
                         pattern_map = self.propagate_up_typemap_info(pattern_map)
                         else_map = self.propagate_up_typemap_info(else_map)
                         self.remove_capture_conflicts(pattern_type.captures, inferred_types)