Add breaking change notice for #44660
Bug: https://github.com/dart-lang/sdk/issues/44660
Change-Id: Ie0760c933a8adbc8b5964e38681c3f9e9dfef114
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/179584
Reviewed-by: Leaf Petersen <leafp@google.com>
Reviewed-by: Kevin Moore <kevmoo@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a6ea3d3..01e66a5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,15 +2,21 @@
### Language
-**Breaking Change** [Null
-Safety](https://dart.dev/null-safety/understanding-null-safety) is now enabled
-by default in all packages with a lower sdk constraint of 2.12.0 or greater.
-Files that are not subject to language versioning (whether because they are not
-contained in a pub package, or because the package that they are contained in
-has no lower sdk constraint) are treated as opted into to null safety by default
-and may report new errors. Pub packages may be opted out of null safety by
-setting a min sdk constraint in pubspec.yaml of 2.9.0 or less. Files may be
-opted out of null safety by adding `// @dart=2.9` to the beginning of the file.
+* **Breaking Change** [Null
+ Safety](https://dart.dev/null-safety/understanding-null-safety) is now
+ enabled by default in all packages with a lower sdk constraint of 2.12.0 or
+ greater. Files that are not subject to language versioning (whether because
+ they are not contained in a pub package, or because the package that they
+ are contained in has no lower sdk constraint) are treated as opted into to
+ null safety by default and may report new errors. Pub packages may be opted
+ out of null safety by setting a min sdk constraint in pubspec.yaml of 2.9.0
+ or less. Files may be opted out of null safety by adding `// @dart=2.9` to
+ the beginning of the file.
+
+* **Breaking Change** [#44660][]: Fixed an implementation bug where `this`
+ would sometimes undergo type promotion in extensions.
+
+[#44660]: https://github.com/dart-lang/sdk/issues/44660
### Core libraries
