diff --git a/DEPS b/DEPS
index 0353d74..94da789 100644
--- a/DEPS
+++ b/DEPS
@@ -44,7 +44,7 @@
   # co19 is a cipd package. Use update.sh in tests/co19[_2] to update these
   # hashes. It requires access to the dart-build-access group, which EngProd
   # has.
-  "co19_rev": "12eb7bb3dd199c817babce7eb65266b90eb8deca",
+  "co19_rev": "28b7e665580cecdf64bc3c81c5b4ed137380c33d",
   "co19_2_rev": "e48b3090826cf40b8037648f19d211e8eab1b4b6",
 
   # The internal benchmarks to use. See go/dart-benchmarks-internal
diff --git a/pkg/analyzer/lib/error/error.dart b/pkg/analyzer/lib/error/error.dart
index 21485aa..3030d6d 100644
--- a/pkg/analyzer/lib/error/error.dart
+++ b/pkg/analyzer/lib/error/error.dart
@@ -465,7 +465,6 @@
   FfiCode.SUBTYPE_OF_STRUCT_CLASS_IN_EXTENDS,
   FfiCode.SUBTYPE_OF_STRUCT_CLASS_IN_IMPLEMENTS,
   FfiCode.SUBTYPE_OF_STRUCT_CLASS_IN_WITH,
-  HintCode.ASSIGNMENT_OF_DO_NOT_STORE,
   HintCode.CAN_BE_NULL_AFTER_NULL_AWARE,
   HintCode.DEAD_CODE,
   HintCode.DEAD_CODE_CATCH_FOLLOWING_CATCH,
diff --git a/pkg/analyzer/lib/src/dart/ast/extensions.dart b/pkg/analyzer/lib/src/dart/ast/extensions.dart
index 0854bf3..fd66ae4 100644
--- a/pkg/analyzer/lib/src/dart/ast/extensions.dart
+++ b/pkg/analyzer/lib/src/dart/ast/extensions.dart
@@ -3,29 +3,8 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/dart/ast/ast.dart';
-import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/ast/ast.dart';
 
-extension ElementExtension on Element {
-  /// Return `true` if this element, the enclosing class (if there is one), or
-  /// the enclosing library, has been annotated with the `@doNotStore`
-  /// annotation.
-  bool get hasOrInheritsDoNotStore {
-    if (hasDoNotStore) {
-      return true;
-    }
-    var ancestor = enclosingElement;
-    if (ancestor is ClassElement || ancestor is ExtensionElement) {
-      if (ancestor.hasDoNotStore) {
-        return true;
-      }
-      ancestor = ancestor.enclosingElement;
-    }
-    return ancestor is CompilationUnitElement &&
-        ancestor.enclosingElement.hasDoNotStore;
-  }
-}
-
 extension ListOfFormalParameterExtension on List<FormalParameter> {
   Iterable<FormalParameterImpl> get asImpl {
     return cast<FormalParameterImpl>();
diff --git a/pkg/analyzer/lib/src/dart/error/hint_codes.dart b/pkg/analyzer/lib/src/dart/error/hint_codes.dart
index 212ad92..b9ce65f 100644
--- a/pkg/analyzer/lib/src/dart/error/hint_codes.dart
+++ b/pkg/analyzer/lib/src/dart/error/hint_codes.dart
@@ -15,14 +15,6 @@
  */
 class HintCode extends AnalyzerErrorCode {
   /**
-   * Users should not assign values marked `@doNotStore`.
-   */
-  static const HintCode ASSIGNMENT_OF_DO_NOT_STORE = HintCode(
-      'ASSIGNMENT_OF_DO_NOT_STORE',
-      "'{0}' is marked 'doNotStore' and shouldn't be assigned to a field.",
-      correction: "Try removing the assignment.");
-
-  /**
    * When the target expression uses '?.' operator, it can be `null`, so all the
    * subsequent invocations should also use '?.' operator.
    */
diff --git a/pkg/analyzer/lib/src/error/best_practices_verifier.dart b/pkg/analyzer/lib/src/error/best_practices_verifier.dart
index f010244..6eff16b 100644
--- a/pkg/analyzer/lib/src/error/best_practices_verifier.dart
+++ b/pkg/analyzer/lib/src/error/best_practices_verifier.dart
@@ -13,7 +13,6 @@
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/dart/element/type_provider.dart';
 import 'package:analyzer/error/listener.dart';
-import 'package:analyzer/src/dart/ast/extensions.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/inheritance_manager3.dart';
 import 'package:analyzer/src/dart/element/member.dart' show ExecutableMember;
@@ -336,37 +335,6 @@
               field.name,
               [field.name, overriddenElement.enclosingElement.name]);
         }
-
-        var expression = field.initializer;
-
-        Element element;
-        if (expression is PropertyAccess) {
-          element = expression.propertyName.staticElement;
-          // Tear-off.
-          if (element is FunctionElement || element is MethodElement) {
-            element = null;
-          }
-        } else if (expression is MethodInvocation) {
-          element = expression.methodName.staticElement;
-        } else if (expression is Identifier) {
-          element = expression.staticElement;
-          // Tear-off.
-          if (element is FunctionElement || element is MethodElement) {
-            element = null;
-          }
-        }
-        if (element != null) {
-          if (element.isSynthetic) {
-            element = (element as PropertyAccessorElement).variable;
-          }
-          if (element.hasOrInheritsDoNotStore) {
-            _errorReporter.reportErrorForNode(
-              HintCode.ASSIGNMENT_OF_DO_NOT_STORE,
-              expression,
-              [element.name],
-            );
-          }
-        }
       }
     } finally {
       _inDeprecatedMember = wasInDeprecatedMember;
diff --git a/pkg/analyzer/lib/src/test_utilities/mock_packages.dart b/pkg/analyzer/lib/src/test_utilities/mock_packages.dart
index 88d5bc0..28eeeae 100644
--- a/pkg/analyzer/lib/src/test_utilities/mock_packages.dart
+++ b/pkg/analyzer/lib/src/test_utilities/mock_packages.dart
@@ -25,7 +25,6 @@
 library meta;
 
 const _AlwaysThrows alwaysThrows = const _AlwaysThrows();
-const _DoNotStore doNotStore = _DoNotStore();
 const _Factory factory = const _Factory();
 const Immutable immutable = const Immutable();
 const _Literal literal = const _Literal();
@@ -37,19 +36,16 @@
 const _Sealed sealed = const _Sealed();
 const _VisibleForTesting visibleForTesting = const _VisibleForTesting();
 
-class _AlwaysThrows {
-  const _AlwaysThrows();
-}
-class _DoNotStore {
-  const _DoNotStore();
-}
-class _Factory {
-  const _Factory();
-}
 class Immutable {
   final String reason;
   const Immutable([this.reason]);
 }
+class _AlwaysThrows {
+  const _AlwaysThrows();
+}
+class _Factory {
+  const _Factory();
+}
 class _Literal {
   const _Literal();
 }
diff --git a/pkg/analyzer/test/src/diagnostics/assignment_of_do_not_store_test.dart b/pkg/analyzer/test/src/diagnostics/assignment_of_do_not_store_test.dart
deleted file mode 100644
index 18d1264..0000000
--- a/pkg/analyzer/test/src/diagnostics/assignment_of_do_not_store_test.dart
+++ /dev/null
@@ -1,166 +0,0 @@
-// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-import 'package:analyzer/src/error/codes.dart';
-import 'package:test_reflective_loader/test_reflective_loader.dart';
-
-import '../dart/resolution/context_collection_resolution.dart';
-
-main() {
-  defineReflectiveSuite(() {
-    defineReflectiveTests(AssignmentOfDoNotStoreTest);
-  });
-}
-
-@reflectiveTest
-class AssignmentOfDoNotStoreTest extends PubPackageResolutionTest {
-  @override
-  void setUp() {
-    super.setUp();
-    writeTestPackageConfigWithMeta();
-  }
-
-  test_classMemberGetter() async {
-    await assertErrorsInCode('''
-import 'package:meta/meta.dart';
-
-class A {
-  @doNotStore
-  String get v => '';
-}
-
-class B {
-  String f = A().v;
-}
-''', [
-      error(HintCode.ASSIGNMENT_OF_DO_NOT_STORE, 106, 5),
-    ]);
-  }
-
-  test_classMemberVariable() async {
-    await assertErrorsInCode('''
-import 'package:meta/meta.dart';
-
-class A{
-  @doNotStore
-  final f = '';
-}
-
-class B {
-  String f = A().f;
-}
-''', [
-      error(HintCode.ASSIGNMENT_OF_DO_NOT_STORE, 99, 5),
-    ]);
-  }
-
-  test_classStaticGetter() async {
-    await assertErrorsInCode('''
-import 'package:meta/meta.dart';
-
-class A {
-  @doNotStore
-  static String get v => '';
-}
-
-class B {
-  String f = A.v;
-}
-''', [
-      error(HintCode.ASSIGNMENT_OF_DO_NOT_STORE, 113, 3),
-    ]);
-  }
-
-  test_classStaticVariable() async {
-    await assertErrorsInCode('''
-import 'package:meta/meta.dart';
-
-class A{
-  @doNotStore
-  static final f = '';
-}
-
-class B {
-  String f = A.f;
-}
-''', [
-      error(HintCode.ASSIGNMENT_OF_DO_NOT_STORE, 106, 3),
-    ]);
-  }
-
-  test_functionAssignment() async {
-    await assertNoErrorsInCode('''
-import 'package:meta/meta.dart';
-
-@doNotStore
-String g(int i) => '';
-
-class C {
-  String Function(int) f = g;
-}
-''');
-  }
-
-  test_functionReturnValue() async {
-    await assertErrorsInCode('''
-import 'package:meta/meta.dart';
-
-@doNotStore
-String getV() => '';
-
-class A {
-  final f = getV();
-}
-''', [
-      error(HintCode.ASSIGNMENT_OF_DO_NOT_STORE, 90, 6),
-    ]);
-  }
-
-  test_methodReturnValue() async {
-    await assertErrorsInCode('''
-import 'package:meta/meta.dart';
-
-class A {
-  @doNotStore
-  String getV() => '';
-}
-
-class B {
-  final f = A().getV();
-}
-''', [
-      error(HintCode.ASSIGNMENT_OF_DO_NOT_STORE, 106, 10),
-    ]);
-  }
-
-  test_topLevelGetter() async {
-    await assertErrorsInCode('''
-import 'package:meta/meta.dart';
-
-@doNotStore
-String get v => '';
-
-class A {
-  final f = v;
-}
-''', [
-      error(HintCode.ASSIGNMENT_OF_DO_NOT_STORE, 89, 1),
-    ]);
-  }
-
-  test_topLevelVariable() async {
-    await assertErrorsInCode('''
-import 'package:meta/meta.dart';
-
-@doNotStore
-final v = '';
-
-class A {
-  final f = v;
-}
-''', [
-      error(HintCode.ASSIGNMENT_OF_DO_NOT_STORE, 83, 1),
-    ]);
-  }
-}
diff --git a/pkg/analyzer/test/src/diagnostics/test_all.dart b/pkg/analyzer/test/src/diagnostics/test_all.dart
index 5495e4e..9d1aa5b 100644
--- a/pkg/analyzer/test/src/diagnostics/test_all.dart
+++ b/pkg/analyzer/test/src/diagnostics/test_all.dart
@@ -22,7 +22,6 @@
 import 'argument_type_not_assignable_test.dart' as argument_type_not_assignable;
 import 'assert_in_redirecting_constructor_test.dart'
     as assert_in_redirecting_constructor;
-import 'assignment_of_do_not_store_test.dart' as assignment_of_do_not_store;
 import 'assignment_to_const_test.dart' as assignment_to_const;
 import 'assignment_to_final_local_test.dart' as assignment_to_final_local;
 import 'assignment_to_final_no_setter_test.dart'
@@ -653,7 +652,6 @@
     annotation_with_non_class.main();
     argument_type_not_assignable.main();
     assert_in_redirecting_constructor.main();
-    assignment_of_do_not_store.main();
     assignment_to_const.main();
     assignment_to_final_local.main();
     assignment_to_final_no_setter.main();
diff --git a/tools/VERSION b/tools/VERSION
index d90ea8e..6f3f0cf 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 10
 PATCH 0
-PRERELEASE 54
+PRERELEASE 55
 PRERELEASE_PATCH 0
\ No newline at end of file