Version 2.11.0-235.0.dev

Merge commit '23b9cce2a1219a122529d68a4e702ac10bcf7522' into 'dev'
diff --git a/DEPS b/DEPS
index 403ba49..f254878 100644
--- a/DEPS
+++ b/DEPS
@@ -131,7 +131,7 @@
   "pub_rev": "f0c7771b38155d3829a60d60b5dba2784b100811",
   "pub_semver_tag": "v1.4.4",
   "quiver-dart_tag": "246e754fe45cecb6aa5f3f13b4ed61037ff0d784",
-  "resource_rev": "f8e37558a1c4f54550aa463b88a6a831e3e33cd6",
+  "resource_rev": "6b79867d0becf5395e5819a75720963b8298e9a7",
   "root_certificates_rev": "7e5ec82c99677a2e5b95ce296c4d68b0d3378ed8",
   "rust_revision": "b7856f695d65a8ebc846754f97d15814bcb1c244",
   "shelf_static_rev": "v0.2.8",
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_super_constructor_invocation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_super_constructor_invocation_test.dart
index ba495c8..0fe23f1 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_super_constructor_invocation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_super_constructor_invocation_test.dart
@@ -62,7 +62,7 @@
   Future<void> test_named_private() async {
     await resolveTestUnit('''
 class A {
-  A._named(int p); // ignore: unused_element
+  A._named(int p);
 }
 class B extends A {
   B() {}
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_constructor_super_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_constructor_super_test.dart
index 77e3e05..c6a46c6 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_constructor_super_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_constructor_super_test.dart
@@ -128,7 +128,7 @@
   Future<void> test_private() async {
     await resolveTestUnit('''
 class A {
-  A._named(p); // ignore: unused_element
+  A._named(p);
 }
 class B extends A {
 }
diff --git a/pkg/analyzer/lib/error/error.dart b/pkg/analyzer/lib/error/error.dart
index aba9652..30ed3d0 100644
--- a/pkg/analyzer/lib/error/error.dart
+++ b/pkg/analyzer/lib/error/error.dart
@@ -481,6 +481,7 @@
   HintCode.DEPRECATED_MIXIN_FUNCTION,
   HintCode.DIVISION_OPTIMIZATION,
   HintCode.DUPLICATE_HIDDEN_NAME,
+  HintCode.DUPLICATE_IGNORE,
   HintCode.DUPLICATE_IMPORT,
   HintCode.DUPLICATE_SHOWN_NAME,
   HintCode.EQUAL_ELEMENTS_IN_SET,
@@ -560,7 +561,9 @@
   HintCode.TYPE_CHECK_IS_NULL,
   HintCode.UNDEFINED_HIDDEN_NAME,
   HintCode.UNDEFINED_SHOWN_NAME,
+  HintCode.UNIGNORABLE_IGNORE,
   HintCode.UNNECESSARY_CAST,
+  HintCode.UNNECESSARY_IGNORE,
   HintCode.UNNECESSARY_NO_SUCH_METHOD,
   HintCode.UNNECESSARY_NULL_COMPARISON_FALSE,
   HintCode.UNNECESSARY_NULL_COMPARISON_TRUE,
diff --git a/pkg/analyzer/lib/src/dart/analysis/file_state.dart b/pkg/analyzer/lib/src/dart/analysis/file_state.dart
index 0a3dee5..2524193 100644
--- a/pkg/analyzer/lib/src/dart/analysis/file_state.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/file_state.dart
@@ -13,7 +13,6 @@
 import 'package:analyzer/dart/ast/standard_ast_factory.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
-import 'package:analyzer/error/error.dart';
 import 'package:analyzer/error/listener.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
@@ -27,7 +26,6 @@
 import 'package:analyzer/src/dart/ast/ast.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart';
-import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/source.dart';
@@ -590,7 +588,11 @@
 ''');
     }
 
-    _setLanguageVersion(unit, scanner.languageVersion, errorListener);
+    var unitImpl = unit as CompilationUnitImpl;
+    unitImpl.languageVersion = LibraryLanguageVersion(
+      package: packageLanguageVersion,
+      override: scanner.overrideVersion,
+    );
 
     // StringToken uses a static instance of StringCanonicalizer, so we need
     // to clear it explicitly once we are done using it for this file.
@@ -613,38 +615,6 @@
     return directive.uri;
   }
 
-  /// Set the language version for the file, from the [versionToken], or from
-  /// the package language version.
-  void _setLanguageVersion(
-    CompilationUnit unit,
-    LanguageVersionToken versionToken,
-    AnalysisErrorListener errorListener,
-  ) {
-    Version overrideVersion;
-    if (versionToken != null) {
-      overrideVersion = Version(versionToken.major, versionToken.minor, 0);
-      var latestVersion = ExperimentStatus.currentVersion;
-      if (overrideVersion > latestVersion) {
-        errorListener.onError(
-          AnalysisError(
-            source,
-            versionToken.offset,
-            versionToken.length,
-            HintCode.INVALID_LANGUAGE_VERSION_OVERRIDE_GREATER,
-            [latestVersion.major, latestVersion.minor],
-          ),
-        );
-        overrideVersion = null;
-      }
-    }
-
-    var unitImpl = unit as CompilationUnitImpl;
-    unitImpl.languageVersion = LibraryLanguageVersion(
-      package: packageLanguageVersion,
-      override: overrideVersion,
-    );
-  }
-
   static UnlinkedUnit2Builder serializeAstUnlinked2(CompilationUnit unit) {
     var exports = <UnlinkedNamespaceDirectiveBuilder>[];
     var imports = <UnlinkedNamespaceDirectiveBuilder>[];
@@ -847,6 +817,19 @@
     return featureSetProvider.getFeatureSet(path, uri);
   }
 
+  Version contextLanguageVersion(
+    String path,
+    Uri uri,
+    WorkspacePackage workspacePackage,
+  ) {
+    var workspaceLanguageVersion = workspacePackage?.languageVersion;
+    if (workspaceLanguageVersion != null) {
+      return workspaceLanguageVersion;
+    }
+
+    return featureSetProvider.getLanguageVersion(path, uri);
+  }
+
   /// Return the canonical [FileState] for the given absolute [path]. The
   /// returned file has the last known state since if was last refreshed.
   ///
@@ -870,7 +853,7 @@
       WorkspacePackage workspacePackage = _workspace?.findPackageFor(path);
       FeatureSet featureSet = contextFeatureSet(path, uri, workspacePackage);
       Version packageLanguageVersion =
-          featureSetProvider.getLanguageVersion(path, uri);
+          contextLanguageVersion(path, uri, workspacePackage);
       file = FileState._(this, path, uri, uriSource, workspacePackage,
           featureSet, packageLanguageVersion);
       _uriToFile[uri] = file;
@@ -914,7 +897,7 @@
       WorkspacePackage workspacePackage = _workspace?.findPackageFor(path);
       FeatureSet featureSet = contextFeatureSet(path, uri, workspacePackage);
       Version packageLanguageVersion =
-          featureSetProvider.getLanguageVersion(path, uri);
+          contextLanguageVersion(path, uri, workspacePackage);
       file = FileState._(this, path, uri, source, workspacePackage, featureSet,
           packageLanguageVersion);
       _uriToFile[uri] = file;
diff --git a/pkg/analyzer/lib/src/dart/analysis/library_analyzer.dart b/pkg/analyzer/lib/src/dart/analysis/library_analyzer.dart
index a70c405..e6ca405 100644
--- a/pkg/analyzer/lib/src/dart/analysis/library_analyzer.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/library_analyzer.dart
@@ -22,13 +22,13 @@
 import 'package:analyzer/src/dart/element/inheritance_manager3.dart';
 import 'package:analyzer/src/dart/element/type_provider.dart';
 import 'package:analyzer/src/dart/element/type_system.dart';
-import 'package:analyzer/src/dart/error/syntactic_errors.dart';
 import 'package:analyzer/src/dart/resolver/flow_analysis_visitor.dart';
 import 'package:analyzer/src/dart/resolver/legacy_type_asserter.dart';
 import 'package:analyzer/src/dart/resolver/resolution_visitor.dart';
 import 'package:analyzer/src/error/best_practices_verifier.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer/src/error/dead_code_verifier.dart';
+import 'package:analyzer/src/error/ignore_validator.dart';
 import 'package:analyzer/src/error/imports_verifier.dart';
 import 'package:analyzer/src/error/inheritance_override.dart';
 import 'package:analyzer/src/error/language_version_override_verifier.dart';
@@ -181,6 +181,16 @@
 
     _checkForInconsistentLanguageVersionOverride(units);
 
+    // This must happen after all other diagnostics have been computed but
+    // before the list of diagnostics has been filtered.
+    for (var file in _library.libraryFiles) {
+      if (file.source != null) {
+        IgnoreValidator(_getErrorReporter(file), _getErrorListener(file).errors,
+                _fileToIgnoreInfo[file], _fileToLineInfo[file])
+            .reportErrors();
+      }
+    }
+
     timerLibraryAnalyzerVerify.stop();
 
     // Return full results.
@@ -428,39 +438,8 @@
     bool isIgnored(AnalysisError error) {
       var code = error.errorCode;
       // Don't allow error severity issues to be ignored.
-      if (!code.isIgnorable) {
-        // The [code] is not ignorable, but we've allowed a few "privileged"
-        // cases. Each is annotated with an issue which represents technical
-        // debt. Once cleaned up, we may remove this notion of "privileged".
-        // In the case of [CompileTimeErrorCode.IMPORT_INTERNAL_LIBRARY], we may
-        // just decide that it happens enough in tests that it can be declared
-        // an ignorable error, and in practice other back ends will prevent
-        // non-internal code from importing internal code.
-        bool privileged = false;
-
-        if (code == CompileTimeErrorCode.UNDEFINED_FUNCTION ||
-            code == CompileTimeErrorCode.UNDEFINED_PREFIXED_NAME) {
-          // Special case a small number of errors in Flutter code which are
-          // ignored. The erroneous code is found in a conditionally imported
-          // library, which uses a special version of the "dart:ui" library
-          // which the Analyzer does not use during analysis. See
-          // https://github.com/flutter/flutter/issues/52899.
-          if (file.path.contains('flutter')) {
-            privileged = true;
-          }
-        }
-
-        if ((code == CompileTimeErrorCode.IMPORT_INTERNAL_LIBRARY ||
-                code == CompileTimeErrorCode.UNDEFINED_ANNOTATION ||
-                code == ParserErrorCode.NATIVE_FUNCTION_BODY_IN_NON_SDK_CODE) &&
-            (file.path.contains('tests/compiler/dart2js') ||
-                file.path.contains('pkg/compiler/test'))) {
-          // Special case the dart2js language tests. Some of these import
-          // various internal libraries.
-          privileged = true;
-        }
-
-        if (!privileged) return false;
+      if (!IgnoreValidator.isIgnorable(file.path, code)) {
+        return false;
       }
 
       int errorLine = lineInfo.getLocation(error.offset).lineNumber;
diff --git a/pkg/analyzer/lib/src/dart/error/hint_codes.dart b/pkg/analyzer/lib/src/dart/error/hint_codes.dart
index 04450e8..6d31ea1 100644
--- a/pkg/analyzer/lib/src/dart/error/hint_codes.dart
+++ b/pkg/analyzer/lib/src/dart/error/hint_codes.dart
@@ -339,6 +339,18 @@
               "members.");
 
   /**
+   * Parameters:
+   * 0: the name of the diagnostic being ignored
+   */
+  static const HintCode DUPLICATE_IGNORE = HintCode(
+      'DUPLICATE_IGNORE',
+      "The diagnostic '{0}' does not need to be ignored here because it is "
+          "already being ignored.",
+      correction:
+          "Try removing the name from the list, or removing the whole comment "
+          "if this is the only name in the list.");
+
+  /**
    * Duplicate imports.
    *
    * No parameters.
@@ -2350,6 +2362,16 @@
       hasPublishedDocs: true);
 
   /**
+   * Parameters:
+   * 0: the name of the non-diagnostic being ignored
+   */
+  static const HintCode UNIGNORABLE_IGNORE = HintCode(
+      'UNIGNORABLE_IGNORE', "The diagnostic '{0}' can't be ignored.",
+      correction:
+          "Try removing the name from the list, or removing the whole comment "
+          "if this is the only name in the list.");
+
+  /**
    * No parameters.
    */
   // #### Description
@@ -2386,6 +2408,18 @@
       correction: "Try removing the cast.", hasPublishedDocs: true);
 
   /**
+   * Parameters:
+   * 0: the name of the diagnostic being ignored
+   */
+  static const HintCode UNNECESSARY_IGNORE = HintCode(
+      'UNNECESSARY_IGNORE',
+      "The diagnostic '{0}' isn't produced at this location so it doesn't "
+          "need to be ignored.",
+      correction:
+          "Try removing the name from the list, or removing the whole comment "
+          "if this is the only name in the list.");
+
+  /**
    * Unnecessary `noSuchMethod` declaration.
    */
   static const HintCode UNNECESSARY_NO_SUCH_METHOD = HintCode(
diff --git a/pkg/analyzer/lib/src/dart/micro/library_analyzer.dart b/pkg/analyzer/lib/src/dart/micro/library_analyzer.dart
index 32a7b18..0695ce0 100644
--- a/pkg/analyzer/lib/src/dart/micro/library_analyzer.dart
+++ b/pkg/analyzer/lib/src/dart/micro/library_analyzer.dart
@@ -28,6 +28,7 @@
 import 'package:analyzer/src/error/best_practices_verifier.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer/src/error/dead_code_verifier.dart';
+import 'package:analyzer/src/error/ignore_validator.dart';
 import 'package:analyzer/src/error/imports_verifier.dart';
 import 'package:analyzer/src/error/inheritance_override.dart';
 import 'package:analyzer/src/error/override_verifier.dart';
@@ -245,6 +246,16 @@
         }
       });
     }
+
+    // This must happen after all other diagnostics have been computed but
+    // before the list of diagnostics has been filtered.
+    for (var file in _library.libraryFiles) {
+      if (file.source != null) {
+        IgnoreValidator(_getErrorReporter(file), _getErrorListener(file).errors,
+                _fileToIgnoreInfo[file], _fileToLineInfo[file])
+            .reportErrors();
+      }
+    }
   }
 
   void _computeHints(FileState file, CompilationUnit unit) {
diff --git a/pkg/analyzer/lib/src/dart/micro/library_graph.dart b/pkg/analyzer/lib/src/dart/micro/library_graph.dart
index d116df5..527a89b 100644
--- a/pkg/analyzer/lib/src/dart/micro/library_graph.dart
+++ b/pkg/analyzer/lib/src/dart/micro/library_graph.dart
@@ -521,6 +521,19 @@
     return featureSetProvider.getFeatureSet(path, uri);
   }
 
+  Version contextLanguageVersion(
+    String path,
+    Uri uri,
+    WorkspacePackage workspacePackage,
+  ) {
+    var workspaceLanguageVersion = workspacePackage?.languageVersion;
+    if (workspaceLanguageVersion != null) {
+      return workspaceLanguageVersion;
+    }
+
+    return featureSetProvider.getLanguageVersion(path, uri);
+  }
+
   FileState getFileForPath({
     @required String path,
     @required OperationPerformanceImpl performance,
@@ -536,7 +549,7 @@
       var workspacePackage = _workspace?.findPackageFor(path);
       var featureSet = contextFeatureSet(path, uri, workspacePackage);
       var packageLanguageVersion =
-          featureSetProvider.getLanguageVersion(path, uri);
+          contextLanguageVersion(path, uri, workspacePackage);
       file = FileState._(this, path, uri, source, workspacePackage, featureSet,
           packageLanguageVersion);
 
@@ -567,7 +580,7 @@
       var workspacePackage = _workspace?.findPackageFor(path);
       var featureSet = contextFeatureSet(path, uri, workspacePackage);
       var packageLanguageVersion =
-          featureSetProvider.getLanguageVersion(path, uri);
+          contextLanguageVersion(path, uri, workspacePackage);
 
       file = FileState._(this, path, uri, source, workspacePackage, featureSet,
           packageLanguageVersion);
diff --git a/pkg/analyzer/lib/src/dart/scanner/scanner.dart b/pkg/analyzer/lib/src/dart/scanner/scanner.dart
index 7266b2d..56ff5ef 100644
--- a/pkg/analyzer/lib/src/dart/scanner/scanner.dart
+++ b/pkg/analyzer/lib/src/dart/scanner/scanner.dart
@@ -10,8 +10,10 @@
 import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/error/listener.dart';
+import 'package:analyzer/src/dart/analysis/experiments.dart';
 import 'package:analyzer/src/dart/error/syntactic_errors.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
+import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:meta/meta.dart';
 import 'package:pub_semver/pub_semver.dart';
@@ -63,7 +65,7 @@
   /// Use [configureFeatures] rather than this field.
   bool enableNonNullable = false;
 
-  fasta.LanguageVersionToken _languageVersion;
+  Version _overrideVersion;
 
   FeatureSet _featureSet;
 
@@ -99,7 +101,7 @@
 
   /// The language version override specified for this compilation unit using a
   /// token like '// @dart = 2.7', or `null` if no override is specified.
-  fasta.LanguageVersionToken get languageVersion => _languageVersion;
+  Version get overrideVersion => _overrideVersion;
 
   set preserveComments(bool preserveComments) {
     _preserveComments = preserveComments;
@@ -186,12 +188,30 @@
   }
 
   void _languageVersionChanged(
-      fasta.Scanner scanner, fasta.LanguageVersionToken languageVersion) {
-    if (languageVersion.major >= 0 && languageVersion.minor >= 0) {
-      _languageVersion = languageVersion;
+      fasta.Scanner scanner, fasta.LanguageVersionToken versionToken) {
+    var overrideMajor = versionToken.major;
+    var overrideMinor = versionToken.minor;
+    if (overrideMajor < 0 || overrideMinor < 0) {
+      return;
+    }
+    _overrideVersion = Version(overrideMajor, overrideMinor, 0);
+
+    var latestVersion = ExperimentStatus.currentVersion;
+    if (overrideVersion > latestVersion) {
+      _errorListener.onError(
+        AnalysisError(
+          source,
+          versionToken.offset,
+          versionToken.length,
+          HintCode.INVALID_LANGUAGE_VERSION_OVERRIDE_GREATER,
+          [latestVersion.major, latestVersion.minor],
+        ),
+      );
+      _overrideVersion = null;
+    } else {
       if (_featureSet != null) {
         _featureSet = _featureSetForOverriding.restrictToVersion(
-          Version(languageVersion.major, languageVersion.minor, 0),
+          _overrideVersion,
         );
         scanner.configuration = buildConfig(_featureSet);
       }
diff --git a/pkg/analyzer/lib/src/error/best_practices_verifier.dart b/pkg/analyzer/lib/src/error/best_practices_verifier.dart
index 12daf7c3..3b9013c 100644
--- a/pkg/analyzer/lib/src/error/best_practices_verifier.dart
+++ b/pkg/analyzer/lib/src/error/best_practices_verifier.dart
@@ -2010,7 +2010,6 @@
       return true;
     }
     if (element is PropertyAccessorElement &&
-        element.enclosingElement is ClassElement &&
         element.variable.hasVisibleForTemplate) {
       return true;
     }
@@ -2025,7 +2024,6 @@
       return true;
     }
     if (element is PropertyAccessorElement &&
-        element.enclosingElement is ClassElement &&
         element.variable.hasVisibleForTesting) {
       return true;
     }
diff --git a/pkg/analyzer/lib/src/error/ignore_validator.dart b/pkg/analyzer/lib/src/error/ignore_validator.dart
new file mode 100644
index 0000000..9f81675
--- /dev/null
+++ b/pkg/analyzer/lib/src/error/ignore_validator.dart
@@ -0,0 +1,192 @@
+// Copyright (c) 2020, 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/error/error.dart';
+import 'package:analyzer/error/listener.dart';
+import 'package:analyzer/source/line_info.dart';
+import 'package:analyzer/src/dart/error/hint_codes.dart';
+import 'package:analyzer/src/dart/error/syntactic_errors.dart';
+import 'package:analyzer/src/error/codes.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/ignore_comments/ignore_info.dart';
+
+/// Used to validate the ignore comments in a single file.
+class IgnoreValidator {
+  /// The error reporter to which errors are to be reported.
+  final ErrorReporter _errorReporter;
+
+  /// The diagnostics that are reported in the file being analyzed.
+  final List<AnalysisError> _reportedErrors;
+
+  /// The information about the ignore comments in the file being analyzed.
+  final IgnoreInfo _ignoreInfo;
+
+  /// The line info for the file being analyzed.
+  final LineInfo _lineInfo;
+
+  /// A list of the names and unique names of all known error codes that can't
+  /// be ignored. Note that this list is incomplete. Plugins might well define
+  /// diagnostics with a severity of `ERROR`, but we won't be able to flag their
+  /// use because we have no visibility of them here.
+  final Set<String> unignorableNames = {};
+
+  /// Initialize a newly created validator to report any issues with ignore
+  /// comments in the file being analyzed. The diagnostics will be reported to
+  /// the [_errorReporter].
+  IgnoreValidator(this._errorReporter, this._reportedErrors, this._ignoreInfo,
+      this._lineInfo) {
+    var filePath = _errorReporter.source.fullName;
+    for (var code in errorCodeValues) {
+      if (!isIgnorable(filePath, code)) {
+        unignorableNames.add(code.name.toLowerCase());
+        unignorableNames.add(code.uniqueName.toLowerCase());
+      }
+    }
+  }
+
+  /// Report any issues with ignore comments in the file being analyzed.
+  void reportErrors() {
+    if (!_ignoreInfo.hasIgnores) {
+      return;
+    }
+    var ignoredOnLineMap = _ignoreInfo.ignoredOnLine;
+    var ignoredForFile = _ignoreInfo.ignoredForFile;
+    //
+    // Report and remove any un-ignorable or duplicated names.
+    //
+    var namesIgnoredForFile = <String>{};
+    var unignorable = <DiagnosticName>[];
+    var duplicated = <DiagnosticName>[];
+    for (var ignoredName in ignoredForFile) {
+      var name = ignoredName.name;
+      if (unignorableNames.contains(name)) {
+        unignorable.add(ignoredName);
+      } else if (!namesIgnoredForFile.add(name)) {
+        duplicated.add(ignoredName);
+      }
+    }
+    _reportUnknownAndDuplicateIgnores(unignorable, duplicated, ignoredForFile);
+    for (var ignoredOnLine in ignoredOnLineMap.values) {
+      var namedIgnoredOnLine = <String>{};
+      var unignorable = <DiagnosticName>[];
+      var duplicated = <DiagnosticName>[];
+      for (var ignoredName in ignoredOnLine) {
+        var name = ignoredName.name;
+        if (unignorableNames.contains(name)) {
+          unignorable.add(ignoredName);
+        } else if (namesIgnoredForFile.contains(name) ||
+            !namedIgnoredOnLine.add(name)) {
+          duplicated.add(ignoredName);
+        }
+      }
+      _reportUnknownAndDuplicateIgnores(unignorable, duplicated, ignoredOnLine);
+    }
+    //
+    // Remove all of the errors that are actually being ignored.
+    //
+    for (var error in _reportedErrors) {
+      var lineNumber = _lineInfo.getLocation(error.offset).lineNumber;
+      var ignoredOnLine = ignoredOnLineMap[lineNumber];
+
+      ignoredForFile.removeByName(error.ignoreName);
+      ignoredForFile.removeByName(error.ignoreUniqueName);
+
+      ignoredOnLine?.removeByName(error.ignoreName);
+      ignoredOnLine?.removeByName(error.ignoreUniqueName);
+    }
+    //
+    // Report any remaining ignored names as being unnecessary.
+    //
+    _reportUnnecessaryIgnores(ignoredForFile);
+    for (var ignoredOnLine in ignoredOnLineMap.values) {
+      _reportUnnecessaryIgnores(ignoredOnLine);
+    }
+  }
+
+  /// Report the names that are [unignorable] or [duplicated] and remove them
+  /// from the [list] of names from which they were extracted.
+  void _reportUnknownAndDuplicateIgnores(List<DiagnosticName> unignorable,
+      List<DiagnosticName> duplicated, List<DiagnosticName> list) {
+    // TODO(brianwilkerson) Uncomment the code below after the unignorable
+    //  ignores in the Flutter code base have been cleaned up.
+    // for (var unignorableName in unignorable) {
+    //   var name = unignorableName.name;
+    //   _errorReporter.reportErrorForOffset(HintCode.UNIGNORABLE_IGNORE,
+    //       unignorableName.offset, name.length, [name]);
+    //   list.remove(unignorableName);
+    // }
+    for (var ignoredName in duplicated) {
+      var name = ignoredName.name;
+      _errorReporter.reportErrorForOffset(
+          HintCode.DUPLICATE_IGNORE, ignoredName.offset, name.length, [name]);
+      list.remove(ignoredName);
+    }
+  }
+
+  /// Report the [ignoredNames] as being unnecessary.
+  void _reportUnnecessaryIgnores(List<DiagnosticName> ignoredNames) {
+    // TODO(brianwilkerson) Uncomment the code below after the unnecessary
+    //  ignores in the Flutter code base have been cleaned up.
+    // for (var ignoredName in ignoredNames) {
+    //   var name = ignoredName.name;
+    //   _errorReporter.reportErrorForOffset(
+    //       HintCode.UNNECESSARY_IGNORE, ignoredName.offset, name.length,
+    //       [name]);
+    // }
+  }
+
+  static bool isIgnorable(String filePath, ErrorCode code) {
+    if (code.isIgnorable) {
+      return true;
+    }
+    // The [code] is not ignorable, but we've allowed a few "privileged"
+    // cases. Each is annotated with an issue which represents technical
+    // debt. Once cleaned up, we may remove this notion of "privileged".
+    // In the case of [CompileTimeErrorCode.IMPORT_INTERNAL_LIBRARY], we may
+    // just decide that it happens enough in tests that it can be declared
+    // an ignorable error, and in practice other back ends will prevent
+    // non-internal code from importing internal code.
+    if (code == CompileTimeErrorCode.UNDEFINED_FUNCTION ||
+        code == CompileTimeErrorCode.UNDEFINED_PREFIXED_NAME) {
+      // Special case a small number of errors in Flutter code which are
+      // ignored. The erroneous code is found in a conditionally imported
+      // library, which uses a special version of the "dart:ui" library
+      // which the Analyzer does not use during analysis. See
+      // https://github.com/flutter/flutter/issues/52899.
+      if (filePath.contains('flutter')) {
+        return true;
+      }
+    }
+
+    if ((code == CompileTimeErrorCode.IMPORT_INTERNAL_LIBRARY ||
+            code == CompileTimeErrorCode.UNDEFINED_ANNOTATION ||
+            code == ParserErrorCode.NATIVE_FUNCTION_BODY_IN_NON_SDK_CODE) &&
+        (filePath.contains('tests/compiler/dart2js') ||
+            filePath.contains('pkg/compiler/test'))) {
+      // Special case the dart2js language tests. Some of these import
+      // various internal libraries.
+      return true;
+    }
+    return false;
+  }
+}
+
+extension on AnalysisError {
+  String get ignoreName => errorCode.name.toLowerCase();
+
+  String get ignoreUniqueName {
+    String uniqueName = errorCode.uniqueName;
+    int period = uniqueName.indexOf('.');
+    if (period >= 0) {
+      uniqueName = uniqueName.substring(period + 1);
+    }
+    return uniqueName.toLowerCase();
+  }
+}
+
+extension on List<DiagnosticName> {
+  void removeByName(String name) {
+    removeWhere((ignoredName) => ignoredName.name == name);
+  }
+}
diff --git a/pkg/analyzer/lib/src/ignore_comments/ignore_info.dart b/pkg/analyzer/lib/src/ignore_comments/ignore_info.dart
index d019194..6d37999 100644
--- a/pkg/analyzer/lib/src/ignore_comments/ignore_info.dart
+++ b/pkg/analyzer/lib/src/ignore_comments/ignore_info.dart
@@ -8,10 +8,27 @@
 import 'package:analyzer/src/dart/ast/token.dart';
 import 'package:analyzer/src/generated/source.dart';
 
+/// The name and location of a diagnostic name in an ignore comment.
+class DiagnosticName {
+  /// The name of the diagnostic being ignored.
+  final String name;
+
+  /// The offset of the diagnostic in the source file.
+  final int offset;
+
+  /// Initialize a newly created diagnostic name to have the given [name] and
+  /// [offset].
+  DiagnosticName(this.name, this.offset);
+
+  /// Return `true` if this diagnostic name matches the given error code.
+  bool matches(String errorCode) => name == errorCode;
+}
+
 /// Information about analysis `//ignore:` and `//ignore_for_file` comments
 /// within a source file.
 class IgnoreInfo {
   ///  Instance shared by all cases without matches.
+  // ignore: deprecated_member_use_from_same_package
   static final IgnoreInfo _EMPTY_INFO = IgnoreInfo();
 
   /// A regular expression for matching 'ignore' comments.  Produces matches
@@ -34,12 +51,13 @@
 
   /// A table mapping line numbers to the diagnostics that are ignored on that
   /// line.
-  final Map<int, List<_DiagnosticName>> _ignoredOnLine = {};
+  final Map<int, List<DiagnosticName>> _ignoredOnLine = {};
 
   /// A list containing all of the diagnostics that are ignored for the whole
   /// file.
-  final List<_DiagnosticName> _ignoredForFile = [];
+  final List<DiagnosticName> _ignoredForFile = [];
 
+  @Deprecated('Use the constructor IgnoreInfo.forDart')
   IgnoreInfo();
 
   /// Initialize a newly created instance of this class to represent the ignore
@@ -73,6 +91,20 @@
   bool get hasIgnores =>
       _ignoredOnLine.isNotEmpty || _ignoredForFile.isNotEmpty;
 
+  /// Return a list containing all of the diagnostics that are ignored for the
+  /// whole file.
+  List<DiagnosticName> get ignoredForFile => _ignoredForFile.toList();
+
+  /// Return a table mapping line numbers to the diagnostics that are ignored on
+  /// that line.
+  Map<int, List<DiagnosticName>> get ignoredOnLine {
+    Map<int, List<DiagnosticName>> ignoredOnLine = {};
+    for (var entry in _ignoredOnLine.entries) {
+      ignoredOnLine[entry.key] = entry.value.toList();
+    }
+    return ignoredOnLine;
+  }
+
   /// Return `true` if the [errorCode] is ignored at the given [line].
   bool ignoredAt(String errorCode, int line) {
     for (var name in _ignoredForFile) {
@@ -92,16 +124,17 @@
   }
 
   /// Ignore these [errorCodes] at [line].
-  void _addAll(int line, Iterable<_DiagnosticName> errorCodes) {
+  void _addAll(int line, Iterable<DiagnosticName> errorCodes) {
     _ignoredOnLine.putIfAbsent(line, () => []).addAll(errorCodes);
   }
 
   /// Ignore these [errorCodes] in the whole file.
-  void _addAllForFile(Iterable<_DiagnosticName> errorCodes) {
+  void _addAllForFile(Iterable<DiagnosticName> errorCodes) {
     _ignoredForFile.addAll(errorCodes);
   }
 
   /// Calculate ignores for the given [content] with line [info].
+  @Deprecated('Use the constructor IgnoreInfo.forDart')
   static IgnoreInfo calculateIgnores(String content, LineInfo info) {
     Iterable<Match> matches = _IGNORE_MATCHER.allMatches(content);
     Iterable<Match> fileMatches = _IGNORE_FOR_FILE_MATCHER.allMatches(content);
@@ -115,10 +148,10 @@
       // Note that the offsets are not being computed here. This shouldn't
       // affect older clients of this class because none of the previous APIs
       // depended on having offsets.
-      Iterable<_DiagnosticName> codes = match
+      Iterable<DiagnosticName> codes = match
           .group(1)
           .split(',')
-          .map((String code) => _DiagnosticName(code.trim().toLowerCase(), -1));
+          .map((String code) => DiagnosticName(code.trim().toLowerCase(), -1));
       CharacterLocation location = info.getLocation(match.start);
       int lineNumber = location.lineNumber;
       String beforeMatch = content.substring(
@@ -137,32 +170,16 @@
     // older clients of this class because none of the previous APIs depended on
     // having offsets.
     for (Match match in fileMatches) {
-      Iterable<_DiagnosticName> codes = match
+      Iterable<DiagnosticName> codes = match
           .group(1)
           .split(',')
-          .map((String code) => _DiagnosticName(code.trim().toLowerCase(), -1));
+          .map((String code) => DiagnosticName(code.trim().toLowerCase(), -1));
       ignoreInfo._addAllForFile(codes);
     }
     return ignoreInfo;
   }
 }
 
-/// The name and location of a diagnostic name in an ignore comment.
-class _DiagnosticName {
-  /// The name of the diagnostic being ignored.
-  final String name;
-
-  /// The offset of the diagnostic in the source file.
-  final int offset;
-
-  /// Initialize a newly created diagnostic name to have the given [name] and
-  /// [offset].
-  _DiagnosticName(this.name, this.offset);
-
-  /// Return `true` if this diagnostic name matches the given error code.
-  bool matches(String errorCode) => name == errorCode;
-}
-
 extension on CompilationUnit {
   /// Return all of the ignore comments in this compilation unit.
   Iterable<CommentToken> get ignoreComments sync* {
@@ -195,12 +212,16 @@
 extension on CommentToken {
   /// Return the diagnostic names contained in this comment, assuming that it is
   /// a correctly formatted ignore comment.
-  Iterable<_DiagnosticName> get diagnosticNames sync* {
+  Iterable<DiagnosticName> get diagnosticNames sync* {
     int offset = lexeme.indexOf(':') + 1;
     var names = lexeme.substring(offset).split(',');
     offset += this.offset;
     for (var name in names) {
-      yield _DiagnosticName(name.trim().toLowerCase(), offset);
+      var trimmedName = name.trim();
+      if (trimmedName.isNotEmpty) {
+        var innerOffset = name.indexOf(trimmedName);
+        yield DiagnosticName(trimmedName.toLowerCase(), offset + innerOffset);
+      }
       offset += name.length + 1;
     }
   }
diff --git a/pkg/analyzer/lib/src/workspace/bazel.dart b/pkg/analyzer/lib/src/workspace/bazel.dart
index 2c474e6..da3cafa 100644
--- a/pkg/analyzer/lib/src/workspace/bazel.dart
+++ b/pkg/analyzer/lib/src/workspace/bazel.dart
@@ -15,6 +15,7 @@
 import 'package:analyzer/src/util/uri.dart';
 import 'package:analyzer/src/workspace/workspace.dart';
 import 'package:path/path.dart' as path;
+import 'package:pub_semver/pub_semver.dart';
 
 /// Instances of the class `BazelFileUriResolver` resolve `file` URI's by first
 /// resolving file uri's in the expected way, and then by looking in the
@@ -267,11 +268,11 @@
     // Handle files which are given with their location in "bazel-bin", etc.
     // This does not typically happen during usual analysis, but it still could,
     // and it can come up in tests.
-    if ([genfiles, ...binPaths]
-        .any((binPath) => context.isWithin(binPath, folder.path))) {
-      var relative = context.relative(filePath, from: root);
-      return findPackageFor(
-          context.joinAll([root, ...context.split(relative).skip(1)]));
+    for (var binPath in [genfiles, ...binPaths]) {
+      if (context.isWithin(binPath, folder.path)) {
+        return findPackageFor(
+            context.join(root, context.relative(filePath, from: binPath)));
+      }
     }
 
     while (true) {
@@ -502,42 +503,26 @@
   @override
   final BazelWorkspace workspace;
 
-  bool _enabledExperimentsReady = false;
+  bool _buildFileReady = false;
   List<String> _enabledExperiments;
+  Version _languageVersion;
 
   BazelWorkspacePackage(String packageName, this.root, this.workspace)
       : _uriPrefix = 'package:$packageName/';
 
   @override
   List<String> get enabledExperiments {
-    if (_enabledExperimentsReady) {
-      return _enabledExperiments;
-    }
-
-    try {
-      _enabledExperimentsReady = true;
-      var buildContent = workspace.provider
-          .getFolder(root)
-          .getChildAssumingFile('BUILD')
-          .readAsStringSync();
-      var hasNonNullableFlag = buildContent
-          .split('\n')
-          .map((e) => e.trim())
-          .where((e) => !e.startsWith('#'))
-          .map((e) => e.replaceAll(' ', ''))
-          .join()
-          .contains('dart_package(null_safety=True');
-      if (hasNonNullableFlag) {
-        _enabledExperiments = [EnableString.non_nullable];
-      }
-    } on FileSystemException {
-      // ignored
-    }
-
+    _readBuildFile();
     return _enabledExperiments;
   }
 
   @override
+  Version get languageVersion {
+    _readBuildFile();
+    return _languageVersion;
+  }
+
+  @override
   bool contains(Source source) {
     if (source.uri.isScheme('package')) {
       return source.uri.toString().startsWith(_uriPrefix);
@@ -599,4 +584,32 @@
 
     return false;
   }
+
+  void _readBuildFile() {
+    if (_buildFileReady) {
+      return;
+    }
+
+    try {
+      _buildFileReady = true;
+      var buildContent = workspace.provider
+          .getFolder(root)
+          .getChildAssumingFile('BUILD')
+          .readAsStringSync();
+      var hasNonNullableFlag = buildContent
+          .split('\n')
+          .map((e) => e.trim())
+          .where((e) => !e.startsWith('#'))
+          .map((e) => e.replaceAll(' ', ''))
+          .join()
+          .contains('dart_package(null_safety=True');
+      if (hasNonNullableFlag) {
+        _enabledExperiments = [EnableString.non_nullable];
+      } else {
+        _languageVersion = Version.parse('2.9.0');
+      }
+    } on FileSystemException {
+      // ignored
+    }
+  }
 }
diff --git a/pkg/analyzer/lib/src/workspace/workspace.dart b/pkg/analyzer/lib/src/workspace/workspace.dart
index 0b83b88..777f116 100644
--- a/pkg/analyzer/lib/src/workspace/workspace.dart
+++ b/pkg/analyzer/lib/src/workspace/workspace.dart
@@ -7,6 +7,7 @@
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/summary/package_bundle_reader.dart';
 import 'package:analyzer/src/workspace/bazel.dart';
+import 'package:pub_semver/pub_semver.dart';
 
 /// Abstract superclass of classes that provide information about the workspace
 /// in which analysis is being performed.
@@ -44,6 +45,15 @@
   /// Return `null` if this package does not have enabled experiments.
   List<String> get enabledExperiments => null;
 
+  /// Return the language version override for all files in the package.
+  ///
+  /// We use [enabledExperiments] to enable Null Safety for selected packages
+  /// when it is not enabled by default in the SDK, and use [languageVersion]
+  /// to disable Null Safety for packages that are not migrated yet.
+  ///
+  /// Return `null` if this package does not have a language version override.
+  Version get languageVersion => null;
+
   String get root;
 
   Workspace get workspace;
diff --git a/pkg/analyzer/test/src/dart/analysis/base.dart b/pkg/analyzer/test/src/dart/analysis/base.dart
index 738a807..dc79e24 100644
--- a/pkg/analyzer/test/src/dart/analysis/base.dart
+++ b/pkg/analyzer/test/src/dart/analysis/base.dart
@@ -23,6 +23,7 @@
 import 'package:analyzer/src/summary/package_bundle_reader.dart';
 import 'package:analyzer/src/test_utilities/mock_sdk.dart';
 import 'package:analyzer/src/test_utilities/resource_provider_mixin.dart';
+import 'package:pub_semver/pub_semver.dart';
 import 'package:test/test.dart';
 
 /// Finds an [Element] with the given [name].
@@ -98,7 +99,26 @@
           ResourceUriResolver(resourceProvider)
         ]),
         createAnalysisOptions(),
-        packages: Packages.empty,
+        packages: Packages({
+          'test': Package(
+            name: 'test',
+            rootFolder: getFolder(testProject),
+            libFolder: getFolder('$testProject/lib'),
+            languageVersion: Version.parse('2.9.0'),
+          ),
+          'aaa': Package(
+            name: 'aaa',
+            rootFolder: getFolder('/aaa'),
+            libFolder: getFolder('/aaa/lib'),
+            languageVersion: Version.parse('2.9.0'),
+          ),
+          'bbb': Package(
+            name: 'bbb',
+            rootFolder: getFolder('/bbb'),
+            libFolder: getFolder('/bbb/lib'),
+            languageVersion: Version.parse('2.9.0'),
+          ),
+        }),
         enableIndex: true,
         externalSummaries: externalSummaries);
   }
diff --git a/pkg/analyzer/test/src/dart/analysis/driver_resolution_test.dart b/pkg/analyzer/test/src/dart/analysis/driver_resolution_test.dart
index c58b0ca..7f16523 100644
--- a/pkg/analyzer/test/src/dart/analysis/driver_resolution_test.dart
+++ b/pkg/analyzer/test/src/dart/analysis/driver_resolution_test.dart
@@ -781,9 +781,20 @@
   }
 
   test_binaryExpression_gtGtGt() async {
+    var latestLanguageVersionStr = '${ExperimentStatus.currentVersion.major}.'
+        '${ExperimentStatus.currentVersion.minor}';
+
+    writeTestPackageConfig(
+      PackageConfigFileBuilder(),
+      languageVersion: latestLanguageVersionStr,
+    );
+
     writeTestPackageAnalysisOptionsFile(
       AnalysisOptionsFileConfig(
-        experiments: [EnableString.triple_shift],
+        experiments: [
+          EnableString.non_nullable,
+          EnableString.triple_shift,
+        ],
       ),
     );
 
diff --git a/pkg/analyzer/test/src/dart/analysis/driver_test.dart b/pkg/analyzer/test/src/dart/analysis/driver_test.dart
index 0743fd3..7d59c48 100644
--- a/pkg/analyzer/test/src/dart/analysis/driver_test.dart
+++ b/pkg/analyzer/test/src/dart/analysis/driver_test.dart
@@ -2937,7 +2937,7 @@
 
     newFile(a, content: '');
     newFile(b, content: r'''
-import 'package:aaa/a.dart'; // ignore: unused_import
+import 'package:aaa/a.dart';
 A a;
 ''');
 
@@ -2949,7 +2949,7 @@
     await waitForIdleWithoutExceptions();
     expect(allResults, hasLength(1));
     expect(allResults[0].path, b);
-    expect(allResults[0].errors, hasLength(1));
+    expect(allResults[0].errors, hasLength(2));
 
     // Create generated file for `package:aaa/a.dart`.
     var aUri = Uri.parse('package:aaa/a.dart');
diff --git a/pkg/analyzer/test/src/dart/constant/evaluation_test.dart b/pkg/analyzer/test/src/dart/constant/evaluation_test.dart
index cb7aa88..a1753b8 100644
--- a/pkg/analyzer/test/src/dart/constant/evaluation_test.dart
+++ b/pkg/analyzer/test/src/dart/constant/evaluation_test.dart
@@ -17,950 +17,17 @@
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(ConstantVisitorTest);
-    defineReflectiveTests(ConstantVisitorWithConstantUpdate2018Test);
-    defineReflectiveTests(
-        ConstantVisitorWithFlowControlAndSpreadCollectionsTest);
+    defineReflectiveTests(ConstantVisitorWithNullSafetyWithTripleShiftTest);
     defineReflectiveTests(ConstantVisitorWithNullSafetyTest);
   });
 }
 
 @reflectiveTest
-class ConstantVisitorTest extends ConstantVisitorTestSupport {
-  test_visitBinaryExpression_questionQuestion_eager_notNull_notNull() async {
-    await resolveTestCode('''
-const c = 'a' ?? 'b';
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.stringType);
-    expect(result.toStringValue(), 'a');
-  }
-
-  test_visitBinaryExpression_questionQuestion_eager_null_notNull() async {
-    await resolveTestCode('''
-const c = null ?? 'b';
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.stringType);
-    expect(result.toStringValue(), 'b');
-  }
-
-  test_visitBinaryExpression_questionQuestion_eager_null_null() async {
-    await resolveTestCode('''
-const c = null ?? null;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.isNull, isTrue);
-  }
-
-  test_visitConditionalExpression_eager_false_int_int() async {
-    await resolveTestCode('''
-const c = false ? 1 : 0;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0);
-  }
-
-  test_visitConditionalExpression_eager_invalid_int_int() async {
-    await resolveTestCode('''
-const c = null ? 1 : 0;
-''');
-    DartObjectImpl result = _evaluateConstant(
-      'c',
-      errorCodes: [CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL],
-    );
-    expect(result, isNull);
-  }
-
-  test_visitConditionalExpression_eager_true_int_int() async {
-    await resolveTestCode('''
-const c = true ? 1 : 0;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 1);
-  }
-
-  test_visitConditionalExpression_eager_true_int_invalid() async {
-    await resolveTestCode('''
-const c = true ? 1 : x;
-''');
-    DartObjectImpl result = _evaluateConstant(
-      'c',
-      errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT],
-    );
-    if (analysisOptions.experimentStatus.constant_update_2018) {
-      expect(result.toIntValue(), 1);
-    } else {
-      expect(result, isNull);
-    }
-  }
-
-  test_visitConditionalExpression_eager_true_invalid_int() async {
-    await resolveTestCode('''
-const c = true ? x : 0;
-''');
-    DartObjectImpl result = _evaluateConstant(
-      'c',
-      errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT],
-    );
-    expect(result, isNull);
-  }
-
-  test_visitInstanceCreationExpression_bool_fromEnvironment() async {
-    await resolveTestCode('''
-const a = bool.fromEnvironment('a');
-const b = bool.fromEnvironment('b', defaultValue: true);
-''');
-    expect(
-      _evaluateConstant('a'),
-      _boolValue(false),
-    );
-    expect(
-      _evaluateConstant('a', declaredVariables: {'a': 'true'}),
-      _boolValue(true),
-    );
-
-    expect(
-      _evaluateConstant(
-        'b',
-        declaredVariables: {'b': 'bbb'},
-        lexicalEnvironment: {'defaultValue': _boolValue(true)},
-      ),
-      _boolValue(true),
-    );
-  }
-
-  test_visitInstanceCreationExpression_bool_hasEnvironment() async {
-    await resolveTestCode('''
-const a = bool.hasEnvironment('a');
-''');
-    expect(
-      _evaluateConstant('a'),
-      _boolValue(false),
-    );
-
-    expect(
-      _evaluateConstant('a', declaredVariables: {'a': '42'}),
-      _boolValue(true),
-    );
-  }
-
-  test_visitInstanceCreationExpression_int_fromEnvironment() async {
-    await resolveTestCode('''
-const a = int.fromEnvironment('a');
-const b = int.fromEnvironment('b', defaultValue: 42);
-''');
-    expect(
-      _evaluateConstant('a'),
-      _intValue(0),
-    );
-    expect(
-      _evaluateConstant('a', declaredVariables: {'a': '5'}),
-      _intValue(5),
-    );
-
-    expect(
-      _evaluateConstant(
-        'b',
-        declaredVariables: {'b': 'bbb'},
-        lexicalEnvironment: {'defaultValue': _intValue(42)},
-      ),
-      _intValue(42),
-    );
-  }
-
-  test_visitInstanceCreationExpression_string_fromEnvironment() async {
-    await resolveTestCode('''
-const a = String.fromEnvironment('a');
-''');
-    expect(
-      _evaluateConstant('a'),
-      DartObjectImpl(
-        typeSystem,
-        typeProvider.stringType,
-        StringState(''),
-      ),
-    );
-    expect(
-      _evaluateConstant('a', declaredVariables: {'a': 'test'}),
-      DartObjectImpl(
-        typeSystem,
-        typeProvider.stringType,
-        StringState('test'),
-      ),
-    );
-  }
-
-  test_visitIntegerLiteral() async {
-    await resolveTestCode('''
-const double d = 3;
-''');
-    DartObjectImpl result = _evaluateConstant('d');
-    expect(result.type, typeProvider.doubleType);
-    expect(result.toDoubleValue(), 3.0);
-  }
-
-  test_visitPropertyAccess_fromExtension() async {
-    await resolveTestCode('''
-extension ExtObject on Object {
-  int get length => 4;
-}
-
-class B {
-  final l;
-  const B(Object o) : l = o.length;
-}
-
-const b = B('');
-''');
-    _evaluateConstant('b', errorCodes: [
-      CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION,
-      CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION
-    ]);
-  }
-
-  test_visitSimpleIdentifier_className() async {
-    await resolveTestCode('''
-const a = C;
-class C {}
-''');
-    DartObjectImpl result = _evaluateConstant('a');
-    expect(result.type, typeProvider.typeType);
-    assertType(result.toTypeValue(), 'C');
-  }
-
-  test_visitSimpleIdentifier_dynamic() async {
-    await resolveTestCode('''
-const a = dynamic;
-''');
-    DartObjectImpl result = _evaluateConstant('a');
-    expect(result.type, typeProvider.typeType);
-    expect(result.toTypeValue(), typeProvider.dynamicType);
-  }
-
-  test_visitSimpleIdentifier_inEnvironment() async {
-    await resolveTestCode(r'''
-const a = b;
-const b = 3;''');
-    var environment = <String, DartObjectImpl>{
-      'b': DartObjectImpl(typeSystem, typeProvider.intType, IntState(6)),
-    };
-    var result = _evaluateConstant('a', lexicalEnvironment: environment);
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 6);
-  }
-
-  test_visitSimpleIdentifier_notInEnvironment() async {
-    await resolveTestCode(r'''
-const a = b;
-const b = 3;''');
-    var environment = <String, DartObjectImpl>{
-      'c': DartObjectImpl(typeSystem, typeProvider.intType, IntState(6)),
-    };
-    var result = _evaluateConstant('a', lexicalEnvironment: environment);
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 3);
-  }
-
-  test_visitSimpleIdentifier_withoutEnvironment() async {
-    await resolveTestCode(r'''
-const a = b;
-const b = 3;''');
-    var result = _evaluateConstant('a');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 3);
-  }
-
-  DartObjectImpl _boolValue(bool value) {
-    if (identical(value, false)) {
-      return DartObjectImpl(
-        typeSystem,
-        typeProvider.boolType,
-        BoolState.FALSE_STATE,
-      );
-    } else if (identical(value, true)) {
-      return DartObjectImpl(
-        typeSystem,
-        typeProvider.boolType,
-        BoolState.TRUE_STATE,
-      );
-    }
-    fail("Invalid boolean value used in test");
-  }
-
-  DartObjectImpl _intValue(int value) {
-    return DartObjectImpl(
-      typeSystem,
-      typeProvider.intType,
-      IntState(value),
-    );
-  }
-}
-
-class ConstantVisitorTestSupport extends PubPackageResolutionTest {
-  DartObjectImpl _evaluateConstant(
-    String name, {
-    List<ErrorCode> errorCodes,
-    Map<String, String> declaredVariables = const {},
-    Map<String, DartObjectImpl> lexicalEnvironment,
-  }) {
-    var expression = findNode.topVariableDeclarationByName(name).initializer;
-
-    var source = this.result.unit.declaredElement.source;
-    var errorListener = GatheringErrorListener();
-    var errorReporter = ErrorReporter(
-      errorListener,
-      source,
-      isNonNullableByDefault: false,
-    );
-
-    DartObjectImpl result = expression.accept(
-      ConstantVisitor(
-        ConstantEvaluationEngine(
-          DeclaredVariables.fromMap(declaredVariables),
-        ),
-        this.result.libraryElement,
-        errorReporter,
-        lexicalEnvironment: lexicalEnvironment,
-      ),
-    );
-    if (errorCodes == null) {
-      errorListener.assertNoErrors();
-    } else {
-      errorListener.assertErrorsWithCodes(errorCodes);
-    }
-    return result;
-  }
-}
+class ConstantVisitorTest extends ConstantVisitorTestSupport
+    with ConstantVisitorTestCases {}
 
 @reflectiveTest
-class ConstantVisitorWithConstantUpdate2018Test
-    extends ConstantVisitorTestSupport {
-  @override
-  void setUp() {
-    super.setUp();
-    writeTestPackageAnalysisOptionsFile(
-      AnalysisOptionsFileConfig(
-        experiments: [EnableString.triple_shift],
-      ),
-    );
-  }
-
-  test_visitAsExpression_instanceOfSameClass() async {
-    await resolveTestCode('''
-const a = const A();
-const b = a as A;
-class A {
-  const A();
-}
-''');
-    DartObjectImpl resultA = _evaluateConstant('a');
-    DartObjectImpl resultB = _evaluateConstant('b');
-    expect(resultB, resultA);
-  }
-
-  test_visitAsExpression_instanceOfSubclass() async {
-    await resolveTestCode('''
-const a = const B();
-const b = a as A;
-class A {
-  const A();
-}
-class B extends A {
-  const B();
-}
-''');
-    DartObjectImpl resultA = _evaluateConstant('a');
-    DartObjectImpl resultB = _evaluateConstant('b');
-    expect(resultB, resultA);
-  }
-
-  test_visitAsExpression_instanceOfSuperclass() async {
-    await resolveTestCode('''
-const a = const A();
-const b = a as B;
-class A {
-  const A();
-}
-class B extends A {
-  const B();
-}
-''');
-    DartObjectImpl result = _evaluateConstant('b',
-        errorCodes: [CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION]);
-    expect(result, isNull);
-  }
-
-  test_visitAsExpression_instanceOfUnrelatedClass() async {
-    await resolveTestCode('''
-const a = const A();
-const b = a as B;
-class A {
-  const A();
-}
-class B {
-  const B();
-}
-''');
-    DartObjectImpl result = _evaluateConstant('b',
-        errorCodes: [CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION]);
-    expect(result, isNull);
-  }
-
-  test_visitAsExpression_null() async {
-    await resolveTestCode('''
-const a = null;
-const b = a as A;
-class A {}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.nullType);
-  }
-
-  test_visitAsExpression_potentialConst() async {
-    await assertNoErrorsInCode('''
-class A {
-  const A();
-}
-
-class MyClass {
-  final A a;
-  const MyClass(Object o) : a = o as A;
-}
-''');
-  }
-
-  test_visitBinaryExpression_and_bool_known_known() async {
-    await resolveTestCode('''
-const c = false & true;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_and_bool_known_unknown() async {
-    await resolveTestCode('''
-const b = bool.fromEnvironment('y');
-const c = false & b;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_and_bool_unknown_known() async {
-    await resolveTestCode('''
-const a = bool.fromEnvironment('x');
-const c = a & true;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_and_bool_unknown_unknown() async {
-    await resolveTestCode('''
-const a = bool.fromEnvironment('x');
-const b = bool.fromEnvironment('y');
-const c = a & b;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_and_int() async {
-    await resolveTestCode('''
-const c = 3 & 5;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-  }
-
-  test_visitBinaryExpression_and_mixed() async {
-    await resolveTestCode('''
-const c = 3 & false;
-''');
-    _evaluateConstant('c',
-        errorCodes: [CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL_INT]);
-  }
-
-  test_visitBinaryExpression_gtGtGt_negative_fewerBits() async {
-    await resolveTestCode('''
-const c = 0xFFFFFFFF >>> 8;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0xFFFFFF);
-  }
-
-  test_visitBinaryExpression_gtGtGt_negative_moreBits() async {
-    await resolveTestCode('''
-const c = 0xFFFFFFFF >>> 33;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0);
-  }
-
-  test_visitBinaryExpression_gtGtGt_negative_moreThan64Bits() async {
-    await resolveTestCode('''
-const c = 0xFFFFFFFF >>> 65;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0);
-  }
-
-  test_visitBinaryExpression_gtGtGt_negative_negativeBits() async {
-    await resolveTestCode('''
-const c = 0xFFFFFFFF >>> -2;
-''');
-    _evaluateConstant('c',
-        errorCodes: [CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION]);
-  }
-
-  test_visitBinaryExpression_gtGtGt_negative_zeroBits() async {
-    await resolveTestCode('''
-const c = 0xFFFFFFFF >>> 0;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0xFFFFFFFF);
-  }
-
-  test_visitBinaryExpression_gtGtGt_positive_fewerBits() async {
-    await resolveTestCode('''
-const c = 0xFF >>> 3;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0x1F);
-  }
-
-  test_visitBinaryExpression_gtGtGt_positive_moreBits() async {
-    await resolveTestCode('''
-const c = 0xFF >>> 9;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0);
-  }
-
-  test_visitBinaryExpression_gtGtGt_positive_moreThan64Bits() async {
-    await resolveTestCode('''
-const c = 0xFF >>> 65;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0);
-  }
-
-  test_visitBinaryExpression_gtGtGt_positive_negativeBits() async {
-    await resolveTestCode('''
-const c = 0xFF >>> -2;
-''');
-    _evaluateConstant('c',
-        errorCodes: [CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION]);
-  }
-
-  test_visitBinaryExpression_gtGtGt_positive_zeroBits() async {
-    await resolveTestCode('''
-const c = 0xFF >>> 0;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0xFF);
-  }
-
-  test_visitBinaryExpression_or_bool_known_known() async {
-    await resolveTestCode('''
-const c = false | true;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_or_bool_known_unknown() async {
-    await resolveTestCode('''
-const b = bool.fromEnvironment('y');
-const c = false | b;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_or_bool_unknown_known() async {
-    await resolveTestCode('''
-const a = bool.fromEnvironment('x');
-const c = a | true;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_or_bool_unknown_unknown() async {
-    await resolveTestCode('''
-const a = bool.fromEnvironment('x');
-const b = bool.fromEnvironment('y');
-const c = a | b;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_or_int() async {
-    await resolveTestCode('''
-const c = 3 | 5;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-  }
-
-  test_visitBinaryExpression_or_mixed() async {
-    await resolveTestCode('''
-const c = 3 | false;
-''');
-    _evaluateConstant('c',
-        errorCodes: [CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL_INT]);
-  }
-
-  test_visitBinaryExpression_questionQuestion_lazy_notNull_invalid() async {
-    await resolveTestCode('''
-const c = 'a' ?? new C();
-class C {}
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.stringType);
-    expect(result.toStringValue(), 'a');
-  }
-
-  test_visitBinaryExpression_questionQuestion_lazy_notNull_notNull() async {
-    await resolveTestCode('''
-const c = 'a' ?? 'b';
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.stringType);
-    expect(result.toStringValue(), 'a');
-  }
-
-  test_visitBinaryExpression_questionQuestion_lazy_null_invalid() async {
-    await resolveTestCode('''
-const c = null ?? new C();
-class C {}
-''');
-    _evaluateConstant('c', errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT]);
-  }
-
-  test_visitBinaryExpression_questionQuestion_lazy_null_notNull() async {
-    await resolveTestCode('''
-const c = null ?? 'b';
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.stringType);
-    expect(result.toStringValue(), 'b');
-  }
-
-  test_visitBinaryExpression_questionQuestion_lazy_null_null() async {
-    await resolveTestCode('''
-const c = null ?? null;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.isNull, isTrue);
-  }
-
-  test_visitBinaryExpression_xor_bool_known_known() async {
-    await resolveTestCode('''
-const c = false ^ true;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_xor_bool_known_unknown() async {
-    await resolveTestCode('''
-const b = bool.fromEnvironment('y');
-const c = false ^ b;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_xor_bool_unknown_known() async {
-    await resolveTestCode('''
-const a = bool.fromEnvironment('x');
-const c = a ^ true;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_xor_bool_unknown_unknown() async {
-    await resolveTestCode('''
-const a = bool.fromEnvironment('x');
-const b = bool.fromEnvironment('y');
-const c = a ^ b;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.boolType);
-  }
-
-  test_visitBinaryExpression_xor_int() async {
-    await resolveTestCode('''
-const c = 3 ^ 5;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-  }
-
-  test_visitBinaryExpression_xor_mixed() async {
-    await resolveTestCode('''
-const c = 3 ^ false;
-''');
-    _evaluateConstant('c',
-        errorCodes: [CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL_INT]);
-  }
-
-  test_visitConditionalExpression_lazy_false_int_int() async {
-    await resolveTestCode('''
-const c = false ? 1 : 0;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0);
-  }
-
-  test_visitConditionalExpression_lazy_false_int_invalid() async {
-    await resolveTestCode('''
-const c = false ? 1 : new C();
-''');
-    _evaluateConstant('c', errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT]);
-  }
-
-  test_visitConditionalExpression_lazy_false_invalid_int() async {
-    await resolveTestCode('''
-const c = false ? new C() : 0;
-''');
-    DartObjectImpl result = _evaluateConstant('c',
-        errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT]);
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 0);
-  }
-
-  test_visitConditionalExpression_lazy_invalid_int_int() async {
-    await resolveTestCode('''
-const c = 3 ? 1 : 0;
-''');
-    _evaluateConstant('c',
-        errorCodes: [CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL]);
-  }
-
-  test_visitConditionalExpression_lazy_true_int_int() async {
-    await resolveTestCode('''
-const c = true ? 1 : 0;
-''');
-    DartObjectImpl result = _evaluateConstant('c');
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 1);
-  }
-
-  test_visitConditionalExpression_lazy_true_int_invalid() async {
-    await resolveTestCode('''
-const c = true ? 1: new C();
-''');
-    DartObjectImpl result = _evaluateConstant('c',
-        errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT]);
-    expect(result.type, typeProvider.intType);
-    expect(result.toIntValue(), 1);
-  }
-
-  test_visitConditionalExpression_lazy_true_invalid_int() async {
-    await resolveTestCode('''
-const c = true ? new C() : 0;
-class C {}
-''');
-    _evaluateConstant('c', errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT]);
-  }
-
-  test_visitIsExpression_is_instanceOfSameClass() async {
-    await resolveTestCode('''
-const a = const A();
-const b = a is A;
-class A {
-  const A();
-}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), true);
-  }
-
-  test_visitIsExpression_is_instanceOfSubclass() async {
-    await resolveTestCode('''
-const a = const B();
-const b = a is A;
-class A {
-  const A();
-}
-class B extends A {
-  const B();
-}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), true);
-  }
-
-  test_visitIsExpression_is_instanceOfSuperclass() async {
-    await resolveTestCode('''
-const a = const A();
-const b = a is B;
-class A {
-  const A();
-}
-class B extends A {
-  const B();
-}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), false);
-  }
-
-  test_visitIsExpression_is_instanceOfUnrelatedClass() async {
-    await resolveTestCode('''
-const a = const A();
-const b = a is B;
-class A {
-  const A();
-}
-class B {
-  const B();
-}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), false);
-  }
-
-  test_visitIsExpression_is_null() async {
-    await resolveTestCode('''
-const a = null;
-const b = a is A;
-class A {}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), false);
-  }
-
-  test_visitIsExpression_is_null_dynamic() async {
-    await resolveTestCode('''
-const a = null;
-const b = a is dynamic;
-class A {}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), true);
-  }
-
-  test_visitIsExpression_is_null_null() async {
-    await resolveTestCode('''
-const a = null;
-const b = a is Null;
-class A {}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), true);
-  }
-
-  test_visitIsExpression_is_null_object() async {
-    await resolveTestCode('''
-const a = null;
-const b = a is Object;
-class A {}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), true);
-  }
-
-  test_visitIsExpression_isNot_instanceOfSameClass() async {
-    await resolveTestCode('''
-const a = const A();
-const b = a is! A;
-class A {
-  const A();
-}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), false);
-  }
-
-  test_visitIsExpression_isNot_instanceOfSubclass() async {
-    await resolveTestCode('''
-const a = const B();
-const b = a is! A;
-class A {
-  const A();
-}
-class B extends A {
-  const B();
-}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), false);
-  }
-
-  test_visitIsExpression_isNot_instanceOfSuperclass() async {
-    await resolveTestCode('''
-const a = const A();
-const b = a is! B;
-class A {
-  const A();
-}
-class B extends A {
-  const B();
-}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), true);
-  }
-
-  test_visitIsExpression_isNot_instanceOfUnrelatedClass() async {
-    await resolveTestCode('''
-const a = const A();
-const b = a is! B;
-class A {
-  const A();
-}
-class B {
-  const B();
-}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), true);
-  }
-
-  test_visitIsExpression_isNot_null() async {
-    await resolveTestCode('''
-const a = null;
-const b = a is! A;
-class A {}
-''');
-    DartObjectImpl result = _evaluateConstant('b');
-    expect(result.type, typeProvider.boolType);
-    expect(result.toBoolValue(), true);
-  }
-}
-
-@reflectiveTest
-class ConstantVisitorWithFlowControlAndSpreadCollectionsTest
-    extends ConstantVisitorTestSupport {
+mixin ConstantVisitorTestCases on ConstantVisitorTestSupport {
   test_listLiteral_ifElement_false_withElse() async {
     await resolveTestCode('''
 const c = [1, if (1 < 0) 2 else 3, 4];
@@ -1151,6 +218,835 @@
     expect(result.type, typeProvider.setType2(typeProvider.intType));
     expect(result.toSetValue().map((e) => e.toIntValue()), [1, 2, 3, 4]);
   }
+
+  test_visitAsExpression_instanceOfSameClass() async {
+    await resolveTestCode('''
+const a = const A();
+const b = a as A;
+class A {
+  const A();
+}
+''');
+    DartObjectImpl resultA = _evaluateConstant('a');
+    DartObjectImpl resultB = _evaluateConstant('b');
+    expect(resultB, resultA);
+  }
+
+  test_visitAsExpression_instanceOfSubclass() async {
+    await resolveTestCode('''
+const a = const B();
+const b = a as A;
+class A {
+  const A();
+}
+class B extends A {
+  const B();
+}
+''');
+    DartObjectImpl resultA = _evaluateConstant('a');
+    DartObjectImpl resultB = _evaluateConstant('b');
+    expect(resultB, resultA);
+  }
+
+  test_visitAsExpression_instanceOfSuperclass() async {
+    await resolveTestCode('''
+const a = const A();
+const b = a as B;
+class A {
+  const A();
+}
+class B extends A {
+  const B();
+}
+''');
+    DartObjectImpl result = _evaluateConstant('b',
+        errorCodes: [CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION]);
+    expect(result, isNull);
+  }
+
+  test_visitAsExpression_instanceOfUnrelatedClass() async {
+    await resolveTestCode('''
+const a = const A();
+const b = a as B;
+class A {
+  const A();
+}
+class B {
+  const B();
+}
+''');
+    DartObjectImpl result = _evaluateConstant('b',
+        errorCodes: [CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION]);
+    expect(result, isNull);
+  }
+
+  test_visitAsExpression_null() async {
+    await resolveTestCode('''
+const a = null;
+const b = a as A;
+class A {}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.nullType);
+  }
+
+  test_visitAsExpression_potentialConst() async {
+    await assertNoErrorsInCode('''
+class A {
+  const A();
+}
+
+class MyClass {
+  final A a;
+  const MyClass(Object o) : a = o as A;
+}
+''');
+  }
+
+  test_visitBinaryExpression_and_bool_known_known() async {
+    await resolveTestCode('''
+const c = false & true;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_and_bool_known_unknown() async {
+    await resolveTestCode('''
+const b = bool.fromEnvironment('y');
+const c = false & b;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_and_bool_unknown_known() async {
+    await resolveTestCode('''
+const a = bool.fromEnvironment('x');
+const c = a & true;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_and_bool_unknown_unknown() async {
+    await resolveTestCode('''
+const a = bool.fromEnvironment('x');
+const b = bool.fromEnvironment('y');
+const c = a & b;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_and_int() async {
+    await resolveTestCode('''
+const c = 3 & 5;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+  }
+
+  test_visitBinaryExpression_and_mixed() async {
+    await resolveTestCode('''
+const c = 3 & false;
+''');
+    _evaluateConstant('c',
+        errorCodes: [CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL_INT]);
+  }
+
+  test_visitBinaryExpression_or_bool_known_known() async {
+    await resolveTestCode('''
+const c = false | true;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_or_bool_known_unknown() async {
+    await resolveTestCode('''
+const b = bool.fromEnvironment('y');
+const c = false | b;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_or_bool_unknown_known() async {
+    await resolveTestCode('''
+const a = bool.fromEnvironment('x');
+const c = a | true;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_or_bool_unknown_unknown() async {
+    await resolveTestCode('''
+const a = bool.fromEnvironment('x');
+const b = bool.fromEnvironment('y');
+const c = a | b;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_or_int() async {
+    await resolveTestCode('''
+const c = 3 | 5;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+  }
+
+  test_visitBinaryExpression_or_mixed() async {
+    await resolveTestCode('''
+const c = 3 | false;
+''');
+    _evaluateConstant('c',
+        errorCodes: [CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL_INT]);
+  }
+
+  test_visitBinaryExpression_questionQuestion_eager_notNull_notNull() async {
+    await resolveTestCode('''
+const c = 'a' ?? 'b';
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.stringType);
+    expect(result.toStringValue(), 'a');
+  }
+
+  test_visitBinaryExpression_questionQuestion_eager_null_notNull() async {
+    await resolveTestCode('''
+const c = null ?? 'b';
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.stringType);
+    expect(result.toStringValue(), 'b');
+  }
+
+  test_visitBinaryExpression_questionQuestion_eager_null_null() async {
+    await resolveTestCode('''
+const c = null ?? null;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.isNull, isTrue);
+  }
+
+  test_visitBinaryExpression_questionQuestion_lazy_notNull_invalid() async {
+    await resolveTestCode('''
+const c = 'a' ?? new C();
+class C {}
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.stringType);
+    expect(result.toStringValue(), 'a');
+  }
+
+  test_visitBinaryExpression_questionQuestion_lazy_notNull_notNull() async {
+    await resolveTestCode('''
+const c = 'a' ?? 'b';
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.stringType);
+    expect(result.toStringValue(), 'a');
+  }
+
+  test_visitBinaryExpression_questionQuestion_lazy_null_invalid() async {
+    await resolveTestCode('''
+const c = null ?? new C();
+class C {}
+''');
+    _evaluateConstant('c', errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT]);
+  }
+
+  test_visitBinaryExpression_questionQuestion_lazy_null_notNull() async {
+    await resolveTestCode('''
+const c = null ?? 'b';
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.stringType);
+    expect(result.toStringValue(), 'b');
+  }
+
+  test_visitBinaryExpression_questionQuestion_lazy_null_null() async {
+    await resolveTestCode('''
+const c = null ?? null;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.isNull, isTrue);
+  }
+
+  test_visitBinaryExpression_xor_bool_known_known() async {
+    await resolveTestCode('''
+const c = false ^ true;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_xor_bool_known_unknown() async {
+    await resolveTestCode('''
+const b = bool.fromEnvironment('y');
+const c = false ^ b;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_xor_bool_unknown_known() async {
+    await resolveTestCode('''
+const a = bool.fromEnvironment('x');
+const c = a ^ true;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_xor_bool_unknown_unknown() async {
+    await resolveTestCode('''
+const a = bool.fromEnvironment('x');
+const b = bool.fromEnvironment('y');
+const c = a ^ b;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.boolType);
+  }
+
+  test_visitBinaryExpression_xor_int() async {
+    await resolveTestCode('''
+const c = 3 ^ 5;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+  }
+
+  test_visitBinaryExpression_xor_mixed() async {
+    await resolveTestCode('''
+const c = 3 ^ false;
+''');
+    _evaluateConstant('c',
+        errorCodes: [CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL_INT]);
+  }
+
+  test_visitConditionalExpression_eager_false_int_int() async {
+    await resolveTestCode('''
+const c = false ? 1 : 0;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0);
+  }
+
+  test_visitConditionalExpression_eager_invalid_int_int() async {
+    await resolveTestCode('''
+const c = null ? 1 : 0;
+''');
+    DartObjectImpl result = _evaluateConstant(
+      'c',
+      errorCodes: [CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL],
+    );
+    expect(result, isNull);
+  }
+
+  test_visitConditionalExpression_eager_true_int_int() async {
+    await resolveTestCode('''
+const c = true ? 1 : 0;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 1);
+  }
+
+  test_visitConditionalExpression_eager_true_int_invalid() async {
+    await resolveTestCode('''
+const c = true ? 1 : x;
+''');
+    DartObjectImpl result = _evaluateConstant(
+      'c',
+      errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT],
+    );
+    if (analysisOptions.experimentStatus.constant_update_2018) {
+      expect(result.toIntValue(), 1);
+    } else {
+      expect(result, isNull);
+    }
+  }
+
+  test_visitConditionalExpression_eager_true_invalid_int() async {
+    await resolveTestCode('''
+const c = true ? x : 0;
+''');
+    DartObjectImpl result = _evaluateConstant(
+      'c',
+      errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT],
+    );
+    expect(result, isNull);
+  }
+
+  test_visitConditionalExpression_lazy_false_int_int() async {
+    await resolveTestCode('''
+const c = false ? 1 : 0;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0);
+  }
+
+  test_visitConditionalExpression_lazy_false_int_invalid() async {
+    await resolveTestCode('''
+const c = false ? 1 : new C();
+''');
+    _evaluateConstant('c', errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT]);
+  }
+
+  test_visitConditionalExpression_lazy_false_invalid_int() async {
+    await resolveTestCode('''
+const c = false ? new C() : 0;
+''');
+    DartObjectImpl result = _evaluateConstant('c',
+        errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT]);
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0);
+  }
+
+  test_visitConditionalExpression_lazy_invalid_int_int() async {
+    await resolveTestCode('''
+const c = 3 ? 1 : 0;
+''');
+    _evaluateConstant('c',
+        errorCodes: [CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL]);
+  }
+
+  test_visitConditionalExpression_lazy_true_int_int() async {
+    await resolveTestCode('''
+const c = true ? 1 : 0;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 1);
+  }
+
+  test_visitConditionalExpression_lazy_true_int_invalid() async {
+    await resolveTestCode('''
+const c = true ? 1: new C();
+''');
+    DartObjectImpl result = _evaluateConstant('c',
+        errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT]);
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 1);
+  }
+
+  test_visitConditionalExpression_lazy_true_invalid_int() async {
+    await resolveTestCode('''
+const c = true ? new C() : 0;
+class C {}
+''');
+    _evaluateConstant('c', errorCodes: [CompileTimeErrorCode.INVALID_CONSTANT]);
+  }
+
+  test_visitInstanceCreationExpression_bool_fromEnvironment() async {
+    await resolveTestCode('''
+const a = bool.fromEnvironment('a');
+const b = bool.fromEnvironment('b', defaultValue: true);
+''');
+    expect(
+      _evaluateConstant('a'),
+      _boolValue(false),
+    );
+    expect(
+      _evaluateConstant('a', declaredVariables: {'a': 'true'}),
+      _boolValue(true),
+    );
+
+    expect(
+      _evaluateConstant(
+        'b',
+        declaredVariables: {'b': 'bbb'},
+        lexicalEnvironment: {'defaultValue': _boolValue(true)},
+      ),
+      _boolValue(true),
+    );
+  }
+
+  test_visitInstanceCreationExpression_bool_hasEnvironment() async {
+    await resolveTestCode('''
+const a = bool.hasEnvironment('a');
+''');
+    expect(
+      _evaluateConstant('a'),
+      _boolValue(false),
+    );
+
+    expect(
+      _evaluateConstant('a', declaredVariables: {'a': '42'}),
+      _boolValue(true),
+    );
+  }
+
+  test_visitInstanceCreationExpression_int_fromEnvironment() async {
+    await resolveTestCode('''
+const a = int.fromEnvironment('a');
+const b = int.fromEnvironment('b', defaultValue: 42);
+''');
+    expect(
+      _evaluateConstant('a'),
+      _intValue(0),
+    );
+    expect(
+      _evaluateConstant('a', declaredVariables: {'a': '5'}),
+      _intValue(5),
+    );
+
+    expect(
+      _evaluateConstant(
+        'b',
+        declaredVariables: {'b': 'bbb'},
+        lexicalEnvironment: {'defaultValue': _intValue(42)},
+      ),
+      _intValue(42),
+    );
+  }
+
+  test_visitInstanceCreationExpression_string_fromEnvironment() async {
+    await resolveTestCode('''
+const a = String.fromEnvironment('a');
+''');
+    expect(
+      _evaluateConstant('a'),
+      DartObjectImpl(
+        typeSystem,
+        typeProvider.stringType,
+        StringState(''),
+      ),
+    );
+    expect(
+      _evaluateConstant('a', declaredVariables: {'a': 'test'}),
+      DartObjectImpl(
+        typeSystem,
+        typeProvider.stringType,
+        StringState('test'),
+      ),
+    );
+  }
+
+  test_visitIntegerLiteral() async {
+    await resolveTestCode('''
+const double d = 3;
+''');
+    DartObjectImpl result = _evaluateConstant('d');
+    expect(result.type, typeProvider.doubleType);
+    expect(result.toDoubleValue(), 3.0);
+  }
+
+  test_visitIsExpression_is_instanceOfSameClass() async {
+    await resolveTestCode('''
+const a = const A();
+const b = a is A;
+class A {
+  const A();
+}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), true);
+  }
+
+  test_visitIsExpression_is_instanceOfSubclass() async {
+    await resolveTestCode('''
+const a = const B();
+const b = a is A;
+class A {
+  const A();
+}
+class B extends A {
+  const B();
+}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), true);
+  }
+
+  test_visitIsExpression_is_instanceOfSuperclass() async {
+    await resolveTestCode('''
+const a = const A();
+const b = a is B;
+class A {
+  const A();
+}
+class B extends A {
+  const B();
+}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), false);
+  }
+
+  test_visitIsExpression_is_instanceOfUnrelatedClass() async {
+    await resolveTestCode('''
+const a = const A();
+const b = a is B;
+class A {
+  const A();
+}
+class B {
+  const B();
+}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), false);
+  }
+
+  test_visitIsExpression_is_null() async {
+    await resolveTestCode('''
+const a = null;
+const b = a is A;
+class A {}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), false);
+  }
+
+  test_visitIsExpression_is_null_dynamic() async {
+    await resolveTestCode('''
+const a = null;
+const b = a is dynamic;
+class A {}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), true);
+  }
+
+  test_visitIsExpression_is_null_null() async {
+    await resolveTestCode('''
+const a = null;
+const b = a is Null;
+class A {}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), true);
+  }
+
+  test_visitIsExpression_is_null_object() async {
+    await resolveTestCode('''
+const a = null;
+const b = a is Object;
+class A {}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), true);
+  }
+
+  test_visitIsExpression_isNot_instanceOfSameClass() async {
+    await resolveTestCode('''
+const a = const A();
+const b = a is! A;
+class A {
+  const A();
+}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), false);
+  }
+
+  test_visitIsExpression_isNot_instanceOfSubclass() async {
+    await resolveTestCode('''
+const a = const B();
+const b = a is! A;
+class A {
+  const A();
+}
+class B extends A {
+  const B();
+}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), false);
+  }
+
+  test_visitIsExpression_isNot_instanceOfSuperclass() async {
+    await resolveTestCode('''
+const a = const A();
+const b = a is! B;
+class A {
+  const A();
+}
+class B extends A {
+  const B();
+}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), true);
+  }
+
+  test_visitIsExpression_isNot_instanceOfUnrelatedClass() async {
+    await resolveTestCode('''
+const a = const A();
+const b = a is! B;
+class A {
+  const A();
+}
+class B {
+  const B();
+}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), true);
+  }
+
+  test_visitIsExpression_isNot_null() async {
+    await resolveTestCode('''
+const a = null;
+const b = a is! A;
+class A {}
+''');
+    DartObjectImpl result = _evaluateConstant('b');
+    expect(result.type, typeProvider.boolType);
+    expect(result.toBoolValue(), true);
+  }
+
+  test_visitPropertyAccess_fromExtension() async {
+    await resolveTestCode('''
+extension ExtObject on Object {
+  int get length => 4;
+}
+
+class B {
+  final l;
+  const B(Object o) : l = o.length;
+}
+
+const b = B('');
+''');
+    _evaluateConstant('b', errorCodes: [
+      CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION,
+      CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION
+    ]);
+  }
+
+  test_visitSimpleIdentifier_className() async {
+    await resolveTestCode('''
+const a = C;
+class C {}
+''');
+    DartObjectImpl result = _evaluateConstant('a');
+    expect(result.type, typeProvider.typeType);
+    assertType(result.toTypeValue(), 'C');
+  }
+
+  test_visitSimpleIdentifier_dynamic() async {
+    await resolveTestCode('''
+const a = dynamic;
+''');
+    DartObjectImpl result = _evaluateConstant('a');
+    expect(result.type, typeProvider.typeType);
+    expect(result.toTypeValue(), typeProvider.dynamicType);
+  }
+
+  test_visitSimpleIdentifier_inEnvironment() async {
+    await resolveTestCode(r'''
+const a = b;
+const b = 3;''');
+    var environment = <String, DartObjectImpl>{
+      'b': DartObjectImpl(typeSystem, typeProvider.intType, IntState(6)),
+    };
+    var result = _evaluateConstant('a', lexicalEnvironment: environment);
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 6);
+  }
+
+  test_visitSimpleIdentifier_notInEnvironment() async {
+    await resolveTestCode(r'''
+const a = b;
+const b = 3;''');
+    var environment = <String, DartObjectImpl>{
+      'c': DartObjectImpl(typeSystem, typeProvider.intType, IntState(6)),
+    };
+    var result = _evaluateConstant('a', lexicalEnvironment: environment);
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 3);
+  }
+
+  test_visitSimpleIdentifier_withoutEnvironment() async {
+    await resolveTestCode(r'''
+const a = b;
+const b = 3;''');
+    var result = _evaluateConstant('a');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 3);
+  }
+
+  DartObjectImpl _boolValue(bool value) {
+    if (identical(value, false)) {
+      return DartObjectImpl(
+        typeSystem,
+        typeProvider.boolType,
+        BoolState.FALSE_STATE,
+      );
+    } else if (identical(value, true)) {
+      return DartObjectImpl(
+        typeSystem,
+        typeProvider.boolType,
+        BoolState.TRUE_STATE,
+      );
+    }
+    fail("Invalid boolean value used in test");
+  }
+
+  DartObjectImpl _intValue(int value) {
+    return DartObjectImpl(
+      typeSystem,
+      typeProvider.intType,
+      IntState(value),
+    );
+  }
+}
+
+class ConstantVisitorTestSupport extends PubPackageResolutionTest {
+  DartObjectImpl _evaluateConstant(
+    String name, {
+    List<ErrorCode> errorCodes,
+    Map<String, String> declaredVariables = const {},
+    Map<String, DartObjectImpl> lexicalEnvironment,
+  }) {
+    var expression = findNode.topVariableDeclarationByName(name).initializer;
+
+    var source = this.result.unit.declaredElement.source;
+    var errorListener = GatheringErrorListener();
+    var errorReporter = ErrorReporter(
+      errorListener,
+      source,
+      isNonNullableByDefault: false,
+    );
+
+    DartObjectImpl result = expression.accept(
+      ConstantVisitor(
+        ConstantEvaluationEngine(
+          DeclaredVariables.fromMap(declaredVariables),
+        ),
+        this.result.libraryElement,
+        errorReporter,
+        lexicalEnvironment: lexicalEnvironment,
+      ),
+    );
+    if (errorCodes == null) {
+      errorListener.assertNoErrors();
+    } else {
+      errorListener.assertErrorsWithCodes(errorCodes);
+    }
+    return result;
+  }
 }
 
 @reflectiveTest
@@ -1171,3 +1067,115 @@
 ''');
   }
 }
+
+@reflectiveTest
+class ConstantVisitorWithNullSafetyWithTripleShiftTest
+    extends ConstantVisitorTestSupport {
+  @override
+  String get testPackageLanguageVersion =>
+      '${ExperimentStatus.currentVersion.major}.'
+      '${ExperimentStatus.currentVersion.minor}';
+
+  @override
+  void setUp() {
+    super.setUp();
+
+    writeTestPackageAnalysisOptionsFile(
+      AnalysisOptionsFileConfig(
+        experiments: [
+          // TODO(scheglov) https://github.com/dart-lang/sdk/issues/43837
+          EnableString.non_nullable,
+          EnableString.triple_shift,
+        ],
+      ),
+    );
+  }
+
+  test_visitBinaryExpression_gtGtGt_negative_fewerBits() async {
+    await resolveTestCode('''
+const c = 0xFFFFFFFF >>> 8;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0xFFFFFF);
+  }
+
+  test_visitBinaryExpression_gtGtGt_negative_moreBits() async {
+    await resolveTestCode('''
+const c = 0xFFFFFFFF >>> 33;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0);
+  }
+
+  test_visitBinaryExpression_gtGtGt_negative_moreThan64Bits() async {
+    await resolveTestCode('''
+const c = 0xFFFFFFFF >>> 65;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0);
+  }
+
+  test_visitBinaryExpression_gtGtGt_negative_negativeBits() async {
+    await resolveTestCode('''
+const c = 0xFFFFFFFF >>> -2;
+''');
+    _evaluateConstant('c',
+        errorCodes: [CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION]);
+  }
+
+  test_visitBinaryExpression_gtGtGt_negative_zeroBits() async {
+    await resolveTestCode('''
+const c = 0xFFFFFFFF >>> 0;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0xFFFFFFFF);
+  }
+
+  test_visitBinaryExpression_gtGtGt_positive_fewerBits() async {
+    await resolveTestCode('''
+const c = 0xFF >>> 3;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0x1F);
+  }
+
+  test_visitBinaryExpression_gtGtGt_positive_moreBits() async {
+    await resolveTestCode('''
+const c = 0xFF >>> 9;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0);
+  }
+
+  test_visitBinaryExpression_gtGtGt_positive_moreThan64Bits() async {
+    await resolveTestCode('''
+const c = 0xFF >>> 65;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0);
+  }
+
+  test_visitBinaryExpression_gtGtGt_positive_negativeBits() async {
+    await resolveTestCode('''
+const c = 0xFF >>> -2;
+''');
+    _evaluateConstant('c',
+        errorCodes: [CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION]);
+  }
+
+  test_visitBinaryExpression_gtGtGt_positive_zeroBits() async {
+    await resolveTestCode('''
+const c = 0xFF >>> 0;
+''');
+    DartObjectImpl result = _evaluateConstant('c');
+    expect(result.type, typeProvider.intType);
+    expect(result.toIntValue(), 0xFF);
+  }
+}
diff --git a/pkg/analyzer/test/src/dart/micro/file_resolution.dart b/pkg/analyzer/test/src/dart/micro/file_resolution.dart
index 250b588..bc7b664 100644
--- a/pkg/analyzer/test/src/dart/micro/file_resolution.dart
+++ b/pkg/analyzer/test/src/dart/micro/file_resolution.dart
@@ -83,6 +83,7 @@
     sdk = MockSdk(resourceProvider: resourceProvider);
 
     newFile('/workspace/WORKSPACE', content: '');
+    newFile('/workspace/dart/test/BUILD', content: '');
     createFileResolver();
   }
 
diff --git a/pkg/analyzer/test/src/dart/micro/simple_file_resolver_test.dart b/pkg/analyzer/test/src/dart/micro/simple_file_resolver_test.dart
index 5a7a974..327276b 100644
--- a/pkg/analyzer/test/src/dart/micro/simple_file_resolver_test.dart
+++ b/pkg/analyzer/test/src/dart/micro/simple_file_resolver_test.dart
@@ -540,6 +540,9 @@
   }
 
   test_reuse_compatibleOptions() async {
+    newFile('/workspace/dart/aaa/BUILD', content: '');
+    newFile('/workspace/dart/bbb/BUILD', content: '');
+
     var aPath = '/workspace/dart/aaa/lib/a.dart';
     var aResult = await assertErrorsInFile(aPath, r'''
 num a = 0;
@@ -561,12 +564,14 @@
   }
 
   test_reuse_incompatibleOptions_implicitCasts() async {
+    newFile('/workspace/dart/aaa/BUILD', content: '');
     newFile('/workspace/dart/aaa/analysis_options.yaml', content: r'''
 analyzer:
   strong-mode:
     implicit-casts: false
 ''');
 
+    newFile('/workspace/dart/bbb/BUILD', content: '');
     newFile('/workspace/dart/bbb/analysis_options.yaml', content: r'''
 analyzer:
   strong-mode:
diff --git a/pkg/analyzer/test/src/dart/resolution/context_collection_resolution.dart b/pkg/analyzer/test/src/dart/resolution/context_collection_resolution.dart
index 4c28ad0..6f7ba44 100644
--- a/pkg/analyzer/test/src/dart/resolution/context_collection_resolution.dart
+++ b/pkg/analyzer/test/src/dart/resolution/context_collection_resolution.dart
@@ -4,6 +4,7 @@
 
 import 'package:analyzer/dart/analysis/analysis_context.dart';
 import 'package:analyzer/dart/analysis/analysis_context_collection.dart';
+import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/dart/analysis/analysis_context_collection.dart';
@@ -332,6 +333,9 @@
   @override
   String get testFilePath => '$testPackageLibPath/test.dart';
 
+  /// The language version to use by default for `package:test`.
+  String get testPackageLanguageVersion => '2.9';
+
   String get testPackageLibPath => '$testPackageRootPath/lib';
 
   String get testPackageRootPath => '$workspaceRootPath/test';
@@ -368,7 +372,7 @@
     config.add(
       name: 'test',
       rootPath: testPackageRootPath,
-      languageVersion: languageVersion,
+      languageVersion: languageVersion ?? testPackageLanguageVersion,
     );
 
     if (js) {
@@ -422,8 +426,14 @@
 
 mixin WithNullSafetyMixin on PubPackageResolutionTest {
   @override
+  String get testPackageLanguageVersion =>
+      Feature.non_nullable.isEnabledByDefault ? '2.12' : '2.11';
+
+  @override
   bool get typeToStringWithNullability => true;
 
+  /// TODO(scheglov) https://github.com/dart-lang/sdk/issues/43837
+  /// Remove when Null Safety is enabled by default.
   @nonVirtual
   @override
   void setUp() {
diff --git a/pkg/analyzer/test/src/dart/resolution/non_nullable_bazel_workspace_test.dart b/pkg/analyzer/test/src/dart/resolution/non_nullable_bazel_workspace_test.dart
index 517ad52..1168802 100644
--- a/pkg/analyzer/test/src/dart/resolution/non_nullable_bazel_workspace_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/non_nullable_bazel_workspace_test.dart
@@ -61,14 +61,6 @@
     );
     assertNoErrorsInResult();
     assertType(findNode.typeName('int v'), 'int');
-
-    // Legacy in other package.
-    await resolveFileCode(
-      '$workspaceRootPath/dart/aaa/lib/a.dart',
-      'int v = 0;',
-    );
-    assertNoErrorsInResult();
-    assertType(findNode.typeName('int v'), 'int*');
   }
 
   test_buildFile_nonNullable_oneLine_noComma() async {
diff --git a/pkg/analyzer/test/src/diagnostics/duplicate_ignore_test.dart b/pkg/analyzer/test/src/diagnostics/duplicate_ignore_test.dart
new file mode 100644
index 0000000..66d84e5
--- /dev/null
+++ b/pkg/analyzer/test/src/diagnostics/duplicate_ignore_test.dart
@@ -0,0 +1,51 @@
+// Copyright (c) 2020, 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(DuplicateIgnoreTest);
+  });
+}
+
+@reflectiveTest
+class DuplicateIgnoreTest extends PubPackageResolutionTest {
+  test_file() async {
+    await assertErrorsInCode(r'''
+// ignore_for_file: unused_local_variable, unused_local_variable
+void f() {
+  var x = 0;
+}
+''', [
+      error(HintCode.DUPLICATE_IGNORE, 43, 21),
+    ]);
+  }
+
+  test_line() async {
+    await assertErrorsInCode(r'''
+void f() {
+  // ignore: unused_local_variable, unused_local_variable
+  var x = 0;
+}
+''', [
+      error(HintCode.DUPLICATE_IGNORE, 47, 21),
+    ]);
+  }
+
+  test_lineAndFile() async {
+    await assertErrorsInCode(r'''
+// ignore_for_file: unused_local_variable
+void f() {
+  // ignore: unused_local_variable
+  var x = 0;
+}
+''', [
+      error(HintCode.DUPLICATE_IGNORE, 66, 21),
+    ]);
+  }
+}
diff --git a/pkg/analyzer/test/src/diagnostics/invalid_use_of_internal_member_test.dart b/pkg/analyzer/test/src/diagnostics/invalid_use_of_internal_member_test.dart
index ac816b9..2fbaf44 100644
--- a/pkg/analyzer/test/src/diagnostics/invalid_use_of_internal_member_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/invalid_use_of_internal_member_test.dart
@@ -25,9 +25,15 @@
     super.setUp();
     writeTestPackagePubspecYamlFile(PubspecYamlFileConfig());
     writeTestPackageConfig(
-        PackageConfigFileBuilder()
-          ..add(name: 'foo', rootPath: fooPackageRootPath),
-        meta: true);
+      PackageConfigFileBuilder()
+        ..add(
+          name: 'foo',
+          rootPath: fooPackageRootPath,
+          languageVersion: '2.9',
+        ),
+      languageVersion: '2.9',
+      meta: true,
+    );
   }
 
   test_insidePackage() async {
diff --git a/pkg/analyzer/test/src/diagnostics/invalid_use_of_visible_for_template_member_test.dart b/pkg/analyzer/test/src/diagnostics/invalid_use_of_visible_for_template_member_test.dart
index 96eba3d..2e35506 100644
--- a/pkg/analyzer/test/src/diagnostics/invalid_use_of_visible_for_template_member_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/invalid_use_of_visible_for_template_member_test.dart
@@ -252,6 +252,26 @@
     ]);
   }
 
+  test_topLevelVariable() async {
+    newFile('$testPackageLibPath/lib1.dart', content: r'''
+import 'package:angular_meta/angular_meta.dart';
+@visibleForTemplate
+int a = 7;
+''');
+    newFile('$testPackageLibPath/lib2.dart', content: r'''
+import 'lib1.dart';
+
+void main() {
+  a;
+}
+''');
+
+    await _resolveFile('$testPackageLibPath/lib1.dart');
+    await _resolveFile('$testPackageLibPath/lib2.dart', [
+      error(HintCode.INVALID_USE_OF_VISIBLE_FOR_TEMPLATE_MEMBER, 37, 1),
+    ]);
+  }
+
   test_unnamedConstructor() async {
     newFile('$testPackageLibPath/lib1.dart', content: r'''
 import 'package:angular_meta/angular_meta.dart';
diff --git a/pkg/analyzer/test/src/diagnostics/invalid_use_of_visible_for_testing_member_test.dart b/pkg/analyzer/test/src/diagnostics/invalid_use_of_visible_for_testing_member_test.dart
index 80c9b7b..9cbadeb 100644
--- a/pkg/analyzer/test/src/diagnostics/invalid_use_of_visible_for_testing_member_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/invalid_use_of_visible_for_testing_member_test.dart
@@ -287,6 +287,25 @@
     ]);
   }
 
+  test_topLevelVariable() async {
+    newFile('$testPackageRootPath/lib1.dart', content: r'''
+import 'package:meta/meta.dart';
+@visibleForTesting
+int a = 7;
+''');
+    newFile('$testPackageRootPath/lib2.dart', content: r'''
+import 'lib1.dart';
+void main() {
+  a;
+}
+''');
+
+    await _resolveFile('$testPackageRootPath/lib1.dart');
+    await _resolveFile('$testPackageRootPath/lib2.dart', [
+      error(HintCode.INVALID_USE_OF_VISIBLE_FOR_TESTING_MEMBER, 36, 1),
+    ]);
+  }
+
   test_unnamedConstructor() async {
     newFile('$testPackageRootPath/lib1.dart', content: r'''
 import 'package:meta/meta.dart';
diff --git a/pkg/analyzer/test/src/diagnostics/sdk_version_gt_gt_gt_operator_test.dart b/pkg/analyzer/test/src/diagnostics/sdk_version_gt_gt_gt_operator_test.dart
index bcdd907..6ea9193 100644
--- a/pkg/analyzer/test/src/diagnostics/sdk_version_gt_gt_gt_operator_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/sdk_version_gt_gt_gt_operator_test.dart
@@ -18,11 +18,20 @@
 @reflectiveTest
 class SdkVersionGtGtGtOperatorTest extends SdkConstraintVerifierTest {
   @override
+  String get testPackageLanguageVersion =>
+      '${ExperimentStatus.currentVersion.major}.'
+      '${ExperimentStatus.currentVersion.minor}';
+
+  @override
   void setUp() {
     super.setUp();
     writeTestPackageAnalysisOptionsFile(
       AnalysisOptionsFileConfig(
-        experiments: [EnableString.triple_shift],
+        experiments: [
+          // TODO(scheglov) https://github.com/dart-lang/sdk/issues/43837
+          EnableString.non_nullable,
+          EnableString.triple_shift,
+        ],
       ),
     );
   }
diff --git a/pkg/analyzer/test/src/diagnostics/test_all.dart b/pkg/analyzer/test/src/diagnostics/test_all.dart
index 3258ab3..7351538 100644
--- a/pkg/analyzer/test/src/diagnostics/test_all.dart
+++ b/pkg/analyzer/test/src/diagnostics/test_all.dart
@@ -128,6 +128,7 @@
 import 'division_optimization_test.dart' as division_optimization;
 import 'duplicate_definition_test.dart' as duplicate_definition;
 import 'duplicate_hidden_name_test.dart' as duplicate_hidden_name;
+import 'duplicate_ignore_test.dart' as duplicate_ignore;
 import 'duplicate_import_test.dart' as duplicate_import;
 import 'duplicate_named_argument_test.dart' as duplicate_named_argument;
 import 'duplicate_part_test.dart' as duplicate_part;
@@ -613,7 +614,9 @@
 import 'undefined_prefixed_name_test.dart' as undefined_prefixed_name;
 import 'undefined_setter_test.dart' as undefined_setter;
 import 'undefined_shown_name_test.dart' as undefined_shown_name;
+import 'unignorable_ignore_test.dart' as unignorable_ignore;
 import 'unnecessary_cast_test.dart' as unnecessary_cast;
+import 'unnecessary_ignore_test.dart' as unnecessary_ignore;
 import 'unnecessary_no_such_method_test.dart' as unnecessary_no_such_method;
 import 'unnecessary_non_null_assertion_test.dart'
     as unnecessary_non_null_assertion;
@@ -739,6 +742,7 @@
     division_optimization.main();
     duplicate_definition.main();
     duplicate_hidden_name.main();
+    duplicate_ignore.main();
     duplicate_import.main();
     duplicate_named_argument.main();
     duplicate_part.main();
@@ -1062,7 +1066,9 @@
     undefined_prefixed_name.main();
     undefined_setter.main();
     undefined_shown_name.main();
+    unignorable_ignore.main();
     unnecessary_cast.main();
+    unnecessary_ignore.main();
     unnecessary_no_such_method.main();
     unnecessary_non_null_assertion.main();
     unnecessary_null_comparison.main();
diff --git a/pkg/analyzer/test/src/diagnostics/unignorable_ignore_test.dart b/pkg/analyzer/test/src/diagnostics/unignorable_ignore_test.dart
new file mode 100644
index 0000000..33ef317
--- /dev/null
+++ b/pkg/analyzer/test/src/diagnostics/unignorable_ignore_test.dart
@@ -0,0 +1,37 @@
+// Copyright (c) 2020, 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(UnignorableIgnoreTest);
+  });
+}
+
+@reflectiveTest
+class UnignorableIgnoreTest extends PubPackageResolutionTest {
+  @failingTest
+  test_file() async {
+    await assertErrorsInCode(r'''
+// ignore_for_file: top_level_cycle
+var x = 0;
+''', [
+      error(HintCode.UNIGNORABLE_IGNORE, 20, 15),
+    ]);
+  }
+
+  @failingTest
+  test_line() async {
+    await assertErrorsInCode(r'''
+// ignore: top_level_cycle
+var x = 0;
+''', [
+      error(HintCode.UNIGNORABLE_IGNORE, 11, 15),
+    ]);
+  }
+}
diff --git a/pkg/analyzer/test/src/diagnostics/unnecessary_ignore_test.dart b/pkg/analyzer/test/src/diagnostics/unnecessary_ignore_test.dart
new file mode 100644
index 0000000..f7b3beb
--- /dev/null
+++ b/pkg/analyzer/test/src/diagnostics/unnecessary_ignore_test.dart
@@ -0,0 +1,37 @@
+// Copyright (c) 2020, 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(UnnecessaryIgnoreTest);
+  });
+}
+
+@reflectiveTest
+class UnnecessaryIgnoreTest extends PubPackageResolutionTest {
+  @failingTest
+  test_file() async {
+    await assertErrorsInCode(r'''
+// ignore_for_file: unused_local_variable
+void f() {}
+''', [
+      error(HintCode.UNNECESSARY_IGNORE, 20, 21),
+    ]);
+  }
+
+  @failingTest
+  test_line() async {
+    await assertErrorsInCode(r'''
+// ignore: unused_local_variable
+void f() {}
+''', [
+      error(HintCode.UNNECESSARY_IGNORE, 11, 21),
+    ]);
+  }
+}
diff --git a/pkg/analyzer/test/src/diagnostics/use_of_nullable_value_test.dart b/pkg/analyzer/test/src/diagnostics/use_of_nullable_value_test.dart
index d1acc45..aaa54e9 100644
--- a/pkg/analyzer/test/src/diagnostics/use_of_nullable_value_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/use_of_nullable_value_test.dart
@@ -23,7 +23,7 @@
     await assertNoErrorsInCode(r'''
 m() {
   Null x;
-  x as int; // ignore: unnecessary_cast
+  x as int;
 }
 ''');
   }
diff --git a/pkg/analyzer/test/src/summary/top_level_inference_test.dart b/pkg/analyzer/test/src/summary/top_level_inference_test.dart
index 96d5cac..e1a5601 100644
--- a/pkg/analyzer/test/src/summary/top_level_inference_test.dart
+++ b/pkg/analyzer/test/src/summary/top_level_inference_test.dart
@@ -638,7 +638,7 @@
   }
 
   test_initializer_extractProperty_explicitlyTyped_differentLibraryCycle() async {
-    newFile('/a.dart', content: r'''
+    newFile('/test/lib/a.dart', content: r'''
 class C {
   int f = 0;
 }
@@ -648,7 +648,7 @@
 var x = new C().f;
 ''');
     checkElementText(library, r'''
-import 'a.dart';
+import 'package:test/a.dart';
 int x;
 ''');
   }
@@ -669,7 +669,7 @@
   }
 
   test_initializer_extractProperty_explicitlyTyped_sameLibraryCycle() async {
-    newFile('/a.dart', content: r'''
+    newFile('/test/lib/a.dart', content: r'''
 import 'test.dart'; // just do make it part of the library cycle
 class C {
   int f = 0;
@@ -680,13 +680,13 @@
 var x = new C().f;
 ''');
     checkElementText(library, r'''
-import 'a.dart';
+import 'package:test/a.dart';
 int x;
 ''');
   }
 
   test_initializer_extractProperty_implicitlyTyped_differentLibraryCycle() async {
-    newFile('/a.dart', content: r'''
+    newFile('/test/lib/a.dart', content: r'''
 class C {
   var f = 0;
 }
@@ -696,7 +696,7 @@
 var x = new C().f;
 ''');
     checkElementText(library, r'''
-import 'a.dart';
+import 'package:test/a.dart';
 int x;
 ''');
   }
@@ -717,7 +717,7 @@
   }
 
   test_initializer_extractProperty_implicitlyTyped_sameLibraryCycle() async {
-    newFile('/a.dart', content: r'''
+    newFile('/test/lib/a.dart', content: r'''
 import 'test.dart'; // just do make it part of the library cycle
 class C {
   var f = 0;
@@ -728,7 +728,7 @@
 var x = new C().f;
 ''');
     checkElementText(library, r'''
-import 'a.dart';
+import 'package:test/a.dart';
 dynamic x;
 ''');
   }
@@ -2590,7 +2590,7 @@
   }
 
   test_method_OK_single_private_linkThroughOtherLibraryOfCycle() async {
-    newFile('/other.dart', content: r'''
+    newFile('/test/lib/other.dart', content: r'''
 import 'test.dart';
 class B extends A2 {}
 ''');
@@ -2604,7 +2604,7 @@
 }
 ''');
     checkElementText(library, r'''
-import 'other.dart';
+import 'package:test/other.dart';
 class A1 {
   int _foo() {}
 }
@@ -2685,7 +2685,7 @@
   }
 
   Future<LibraryElement> _encodeDecodeLibrary(String text) async {
-    String path = convertPath('/test.dart');
+    String path = convertPath('/test/lib/test.dart');
     newFile(path, content: text);
     UnitElementResult result = await driver.getUnitElement(path);
     return result.element.library;
diff --git a/pkg/analyzer/test/src/workspace/bazel_test.dart b/pkg/analyzer/test/src/workspace/bazel_test.dart
index 0b33c83..2129789 100644
--- a/pkg/analyzer/test/src/workspace/bazel_test.dart
+++ b/pkg/analyzer/test/src/workspace/bazel_test.dart
@@ -776,7 +776,7 @@
   void test_find_hasBlazeBinFolderInOutFolder() {
     _addResources([
       '/workspace/blaze-out/host/bin/',
-      '/workspace/my/module/',
+      '/workspace/my/module/BUILD',
     ]);
     BazelWorkspace workspace = BazelWorkspace.find(
         resourceProvider, convertPath('/workspace/my/module'));
@@ -785,6 +785,12 @@
     expect(workspace.binPaths.single,
         convertPath('/workspace/blaze-out/host/bin'));
     expect(workspace.genfiles, convertPath('/workspace/blaze-genfiles'));
+    expect(
+        workspace
+            .findPackageFor(convertPath(
+                '/workspace/blaze-out/host/bin/my/module/lib/foo.dart'))
+            .root,
+        convertPath('/workspace/my/module'));
   }
 
   void test_find_hasBlazeOutFolder_missingBinFolder() {
diff --git a/pkg/analyzer/test/verify_diagnostics_test.dart b/pkg/analyzer/test/verify_diagnostics_test.dart
index 815b3db..de52dc3 100644
--- a/pkg/analyzer/test/verify_diagnostics_test.dart
+++ b/pkg/analyzer/test/verify_diagnostics_test.dart
@@ -407,6 +407,7 @@
 
   /// Initialize a newly created test to test the given [snippet].
   _SnippetTest(this.snippet) {
+    // TODO(scheglov) https://github.com/dart-lang/sdk/issues/43837
     writeTestPackageAnalysisOptionsFile(
       AnalysisOptionsFileConfig(
         experiments: snippet.experiments,
@@ -415,6 +416,12 @@
   }
 
   @override
+  String get testPackageLanguageVersion {
+    // TODO(scheglov) https://github.com/dart-lang/sdk/issues/43837
+    return snippet.experiments == null ? '2.9' : null;
+  }
+
+  @override
   void setUp() {
     super.setUp();
     _createAuxiliaryFiles(snippet.auxiliaryFiles);
diff --git a/pkg/dev_compiler/lib/src/kernel/compiler.dart b/pkg/dev_compiler/lib/src/kernel/compiler.dart
index 4b6b47d..31eb2d6 100644
--- a/pkg/dev_compiler/lib/src/kernel/compiler.dart
+++ b/pkg/dev_compiler/lib/src/kernel/compiler.dart
@@ -1776,23 +1776,14 @@
   js_ast.Fun _emitNativeFunctionBody(Procedure node) {
     var name = _annotationName(node, isJSAnnotation) ?? node.name.text;
     if (node.isGetter) {
-      var returnValue = js('this.#', [name]);
-      if (_isNullCheckableNative(node)) {
-        // Add a potential null-check on native getter if type is non-nullable.
-        returnValue = runtimeCall('checkNativeNonNull(#)', [returnValue]);
-      }
-      return js_ast.Fun([], js.block('{ return #; }', [returnValue]));
+      return js_ast.Fun([], js.block('{ return this.#; }', [name]));
     } else if (node.isSetter) {
       var params = _emitParameters(node.function);
       return js_ast.Fun(
           params, js.block('{ this.# = #; }', [name, params.last]));
     } else {
-      var returnValue = js('this.#.apply(this, args)', [name]);
-      if (_isNullCheckableNative(node)) {
-        // Add a potential null-check on return value if type is non-nullable.
-        returnValue = runtimeCall('checkNativeNonNull(#)', [returnValue]);
-      }
-      return js.fun('function (...args) { return #; }', [returnValue]);
+      return js.fun(
+          'function (...args) { return this.#.apply(this, args); }', name);
     }
   }
 
@@ -2279,9 +2270,6 @@
       // Fields on a native class are implicitly native.
       // Methods/getters/setters are marked external/native.
       if (member is Field || _isExternal(member)) {
-        // If the native member needs to be null-checked, we require symbolizing
-        // it in order to access the null-check at the member definition.
-        if (_isNullCheckableNative(member)) return true;
         var jsName = _annotationName(member, isJSName);
         return jsName != null && jsName != name;
       } else {
@@ -4227,8 +4215,14 @@
 
   @override
   js_ast.Expression visitPropertyGet(PropertyGet node) {
-    return _emitPropertyGet(
-        node.receiver, node.interfaceTarget, node.name.text);
+    var propertyGet =
+        _emitPropertyGet(node.receiver, node.interfaceTarget, node.name.text);
+    if (_isCheckableNative(node.interfaceTarget)) {
+      // If target is a native getter with a non-nullable type, add a null check
+      // for soundness.
+      return runtimeCall('checkNativeNonNull(#)', [propertyGet]);
+    }
+    return propertyGet;
   }
 
   @override
@@ -4282,8 +4276,8 @@
   }
 
   /// Return whether [member] returns a native object whose type needs to be
-  /// null-checked. This is true for non-nullable native return types.
-  bool _isNullCheckableNative(Member member) =>
+  /// checked.
+  bool _isCheckableNative(Member member) =>
       member != null &&
       member.isExternal &&
       _extensionTypes.isNativeClass(member.enclosingClass) &&
@@ -4361,8 +4355,14 @@
 
   @override
   js_ast.Expression visitMethodInvocation(MethodInvocation node) {
-    return _emitMethodCall(
+    var methodCall = _emitMethodCall(
         node.receiver, node.interfaceTarget, node.arguments, node);
+    if (_isCheckableNative(node.interfaceTarget)) {
+      // If target is a native method with a non-nullable type, add a null check
+      // for soundness.
+      return runtimeCall('checkNativeNonNull(#)', [methodCall]);
+    }
+    return methodCall;
   }
 
   js_ast.Expression _emitMethodCall(Expression receiver, Member target,
diff --git a/pkg/front_end/lib/src/fasta/builder/class_builder.dart b/pkg/front_end/lib/src/fasta/builder/class_builder.dart
index cea8ff8..6f675d8 100644
--- a/pkg/front_end/lib/src/fasta/builder/class_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/class_builder.dart
@@ -6,28 +6,19 @@
 
 import 'package:kernel/ast.dart'
     show
-        Arguments,
-        AsExpression,
-        AsyncMarker,
         Class,
         Constructor,
         DartType,
         DynamicType,
-        Expression,
         FunctionNode,
         FunctionType,
         FutureOrType,
         InterfaceType,
         Member,
-        MethodInvocation,
         Name,
         Nullability,
-        Procedure,
-        ReturnStatement,
         Supertype,
-        ThisExpression,
         TypeParameter,
-        VoidType,
         getAsTypeArguments;
 
 import 'package:kernel/class_hierarchy.dart' show ClassHierarchy;
@@ -49,8 +40,6 @@
 
 import '../kernel/redirecting_factory_body.dart' show getRedirectingFactoryBody;
 
-import '../kernel/kernel_target.dart' show KernelTarget;
-
 import '../loader.dart';
 
 import '../modifier.dart';
@@ -773,48 +762,6 @@
     return noSuchMethod != null && noSuchMethod.enclosingClass != objectClass;
   }
 
-  void transformProcedureToNoSuchMethodForwarder(
-      Member noSuchMethodInterface, KernelTarget target, Procedure procedure) {
-    String prefix = procedure.isGetter
-        ? 'get:'
-        : procedure.isSetter
-            ? 'set:'
-            : '';
-    String invocationName = prefix + procedure.name.text;
-    if (procedure.isSetter) invocationName += '=';
-    Expression invocation = target.backendTarget.instantiateInvocation(
-        target.loader.coreTypes,
-        new ThisExpression(),
-        invocationName,
-        new Arguments.forwarded(procedure.function, library.library),
-        procedure.fileOffset,
-        /*isSuper=*/ false);
-    Expression result = new MethodInvocation(new ThisExpression(),
-        noSuchMethodName, new Arguments([invocation]), noSuchMethodInterface)
-      ..fileOffset = procedure.fileOffset;
-    if (procedure.function.returnType is! VoidType) {
-      result = new AsExpression(result, procedure.function.returnType)
-        ..isTypeError = true
-        ..isForDynamic = true
-        ..isForNonNullableByDefault = library.isNonNullableByDefault
-        ..fileOffset = procedure.fileOffset;
-    }
-    procedure.function.body = new ReturnStatement(result)
-      ..fileOffset = procedure.fileOffset;
-    procedure.function.body.parent = procedure.function;
-    procedure.function.asyncMarker = AsyncMarker.Sync;
-    procedure.function.dartAsyncMarker = AsyncMarker.Sync;
-
-    procedure.isAbstract = false;
-    procedure.isNoSuchMethodForwarder = true;
-    procedure.isMemberSignature = false;
-    procedure.isForwardingStub = false;
-    procedure.isForwardingSemiStub = false;
-    procedure.memberSignatureOrigin = null;
-    procedure.forwardingStubInterfaceTarget = null;
-    procedure.forwardingStubSuperTarget = null;
-  }
-
   @override
   String get fullNameForErrors {
     return isMixinApplication && !isNamedMixinApplication
@@ -1216,17 +1163,3 @@
 
   ConstructorRedirection(this.target) : cycleReported = false;
 }
-
-/// Returns `true` if override problems should be overlooked.
-///
-/// This is needed for the current encoding of some JavaScript implementation
-/// classes that are not valid Dart. For instance `JSInt` in
-/// 'dart:_interceptors' that implements both `int` and `double`, and `JsArray`
-/// in `dart:js` that implement both `ListMixin` and `JsObject`.
-bool shouldOverrideProblemBeOverlooked(ClassBuilder classBuilder) {
-  String uri = '${classBuilder.library.importUri}';
-  return uri == 'dart:js' &&
-          classBuilder.fileUri.pathSegments.last == 'js.dart' ||
-      uri == 'dart:_interceptors' &&
-          classBuilder.fileUri.pathSegments.last == 'js_number.dart';
-}
diff --git a/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart b/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart
index 9868a51..c08ebe5 100644
--- a/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart
@@ -61,8 +61,6 @@
 
 import '../names.dart' show noSuchMethodName;
 
-import '../problems.dart' show unhandled;
-
 import '../scope.dart' show Scope;
 
 import '../source/source_class_builder.dart';
@@ -81,6 +79,8 @@
 
 import '../type_inference/type_schema_environment.dart' show TypeConstraint;
 
+import 'combined_member_signature.dart';
+
 import 'forwarding_node.dart' show ForwardingNode;
 
 import 'kernel_builder.dart' show ImplicitFieldType;
@@ -684,8 +684,8 @@
       Set<ClassMember> overriddenMemberSet =
           toSet(declaredMember.classBuilder, overriddenMembers);
       if (classBuilder.library.isNonNullableByDefault) {
-        CombinedMemberSignature combinedMemberSignature =
-            new CombinedMemberSignature(
+        CombinedClassMemberSignature combinedMemberSignature =
+            new CombinedClassMemberSignature(
                 hierarchy, classBuilder, overriddenMemberSet.toList(),
                 forSetter: false);
         FunctionType combinedMemberSignatureType = combinedMemberSignature
@@ -1101,8 +1101,8 @@
 
         void inferFrom(List<ClassMember> members, {bool forSetter}) {
           assert(forSetter != null);
-          CombinedMemberSignature combinedMemberSignature =
-              new CombinedMemberSignature(hierarchy, classBuilder, members,
+          CombinedClassMemberSignature combinedMemberSignature =
+              new CombinedClassMemberSignature(hierarchy, classBuilder, members,
                   forSetter: forSetter);
           DartType combinedMemberSignatureType =
               combinedMemberSignature.combinedMemberSignatureType;
@@ -1228,8 +1228,8 @@
 
         void inferFrom(List<ClassMember> members, {bool forSetter}) {
           assert(forSetter != null);
-          CombinedMemberSignature combinedMemberSignature =
-              new CombinedMemberSignature(hierarchy, classBuilder, members,
+          CombinedClassMemberSignature combinedMemberSignature =
+              new CombinedClassMemberSignature(hierarchy, classBuilder, members,
                   forSetter: forSetter);
           DartType combinedMemberSignatureType =
               combinedMemberSignature.combinedMemberSignatureType;
@@ -1392,8 +1392,8 @@
 
         DartType inferFrom(List<ClassMember> members, {bool forSetter}) {
           assert(forSetter != null);
-          CombinedMemberSignature combinedMemberSignature =
-              new CombinedMemberSignature(hierarchy, classBuilder, members,
+          CombinedClassMemberSignature combinedMemberSignature =
+              new CombinedClassMemberSignature(hierarchy, classBuilder, members,
                   forSetter: forSetter);
           return combinedMemberSignature.combinedMemberSignatureType;
         }
@@ -3181,11 +3181,11 @@
           declarations.first.getMember(hierarchy);
     }
 
-    CombinedMemberSignature combinedMemberSignature =
-        new CombinedMemberSignature(hierarchy, classBuilder, declarations,
+    CombinedClassMemberSignature combinedMemberSignature =
+        new CombinedClassMemberSignature(hierarchy, classBuilder, declarations,
             forSetter: isSetter);
 
-    if (combinedMemberSignature.canonicalClassMember == null) {
+    if (combinedMemberSignature.canonicalMember == null) {
       String name = classBuilder.fullNameForErrors;
       int length = classBuilder.isAnonymousMixinApplication ? 1 : name.length;
       List<LocatedMessage> context = declarations.map((ClassMember d) {
@@ -3206,13 +3206,13 @@
           declarations.first.getMember(hierarchy);
     }
     debug?.log("Combined Member Signature of ${fullNameForErrors}: "
-        "${combinedMemberSignature.canonicalClassMember.fullName}");
+        "${combinedMemberSignature.canonicalMember.fullName}");
 
     if (modifyKernel) {
       ProcedureKind kind = ProcedureKind.Method;
       Member bestMemberSoFar =
-          combinedMemberSignature.canonicalClassMember.getMember(hierarchy);
-      if (combinedMemberSignature.canonicalClassMember.isProperty) {
+          combinedMemberSignature.canonicalMember.getMember(hierarchy);
+      if (combinedMemberSignature.canonicalMember.isProperty) {
         kind = isSetter ? ProcedureKind.Setter : ProcedureKind.Getter;
       } else if (bestMemberSoFar is Procedure &&
           bestMemberSoFar.kind == ProcedureKind.Operator) {
@@ -3221,7 +3221,7 @@
 
       debug?.log("Combined Member Signature of ${fullNameForErrors}: new "
           "ForwardingNode($classBuilder, "
-          "${combinedMemberSignature.canonicalClassMember}, "
+          "${combinedMemberSignature.canonicalMember}, "
           "$declarations, $kind)");
       Member stub =
           new ForwardingNode(combinedMemberSignature, kind).finalize();
@@ -3229,7 +3229,7 @@
         classBuilder.cls.addMember(stub);
         SourceLibraryBuilder library = classBuilder.library;
         Member bestMemberSoFar =
-            combinedMemberSignature.canonicalClassMember.getMember(hierarchy);
+            combinedMemberSignature.canonicalMember.getMember(hierarchy);
         if (bestMemberSoFar is Procedure) {
           library.forwardersOrigins..add(stub)..add(bestMemberSoFar);
         }
@@ -3242,7 +3242,7 @@
     debug?.log(
         "Combined Member Signature of ${fullNameForErrors}: picked bestSoFar");
     return combinedMemberSignatureResult =
-        combinedMemberSignature.canonicalClassMember.getMember(hierarchy);
+        combinedMemberSignature.canonicalMember.getMember(hierarchy);
   }
 
   @override
@@ -3342,8 +3342,9 @@
         // This call will add a body to the abstract method if needed for
         // isGenericCovariantImpl checks.
         new ForwardingNode(
-                new CombinedMemberSignature.internal(
-                    hierarchy, classBuilder, 1, declarations),
+                new CombinedClassMemberSignature.internal(
+                    hierarchy, classBuilder, 1, declarations,
+                    forSetter: isSetter),
                 kind)
             .finalize();
       }
@@ -3574,300 +3575,3 @@
     }
   }
 }
-
-/// Class used for computing and inspecting the combined member signature for
-/// a set of overridden/inherited members.
-class CombinedMemberSignature {
-  /// The class hierarchy builder used for building this class.
-  final ClassHierarchyBuilder hierarchy;
-
-  /// The target class for the combined member signature.
-  ///
-  /// The [_memberTypes] are computed in terms of each member is inherited into
-  /// [classBuilder].
-  ///
-  /// [classBuilder] is also used for determining whether the combined member
-  /// signature should be computed using nnbd or legacy semantics.
-  final SourceClassBuilder classBuilder;
-
-  /// The list of the members inherited into or overridden in [classBuilder].
-  final List<ClassMember> members;
-
-  /// The index within [members] for the member whose type is the most specific
-  /// among [members]. If `null`, the combined member signature is not defined
-  /// for [members] in [classBuilder].
-  ///
-  /// For the legacy computation, the type of this member defines the combined
-  /// member signature.
-  ///
-  /// For the nnbd computation, this is one of the members whose type define
-  /// the combined member signature, and the indices of the remaining members
-  /// are stored in [_mutualSubtypes].
-  int _canonicalMemberIndex;
-
-  /// For the nnbd computation, this maps each distinct but most specific member
-  /// type to the index of one of the [members] with that type.
-  ///
-  /// If there is only one most specific member type, this is `null`.
-  Map<DartType, int> _mutualSubtypes;
-
-  /// Cache for the types of [members] as inherited into [classBuilder].
-  List<DartType> _memberTypes;
-
-  /// Cache for the this type of [classBuilder].
-  DartType _thisType;
-
-  /// If `true` the combined member signature type has been computed.
-  ///
-  /// Note that the combined member signature type might be undefined in which
-  /// case [_combinedMemberSignatureType] is `null`.
-  bool _isCombinedMemberSignatureTypeComputed = false;
-
-  /// Cache the computed combined member signature type.
-  ///
-  /// If the combined member signature type is undefined this is set to `null`.
-  DartType _combinedMemberSignatureType;
-
-  /// Creates a [CombinedMemberSignature] whose canonical member is already
-  /// defined.
-  CombinedMemberSignature.internal(this.hierarchy, this.classBuilder,
-      this._canonicalMemberIndex, this.members);
-
-  /// Creates a [CombinedMemberSignature] for [members] inherited into
-  /// [classBuilder].
-  ///
-  /// If [forSetter] is `true`, contravariance of the setter types is used to
-  /// compute the most specific member type. Otherwise covariance of the getter
-  /// types or function types is used.
-  CombinedMemberSignature(this.hierarchy, this.classBuilder, this.members,
-      {bool forSetter}) {
-    assert(forSetter != null);
-    ClassMember bestSoFar;
-    int bestSoFarIndex;
-    if (members.length == 1) {
-      bestSoFar = members.first;
-      bestSoFarIndex = 0;
-    } else {
-      bool isNonNullableByDefault = classBuilder.library.isNonNullableByDefault;
-
-      DartType bestTypeSoFar;
-      for (int candidateIndex = members.length - 1;
-          candidateIndex >= 0;
-          candidateIndex--) {
-        ClassMember candidate = members[candidateIndex];
-        DartType candidateType = getMemberType(candidateIndex);
-        if (bestSoFar == null) {
-          bestSoFar = candidate;
-          bestTypeSoFar = candidateType;
-          bestSoFarIndex = candidateIndex;
-        } else {
-          if (_isMoreSpecific(candidateType, bestTypeSoFar, forSetter)) {
-            if (isNonNullableByDefault &&
-                _isMoreSpecific(bestTypeSoFar, candidateType, forSetter)) {
-              if (_mutualSubtypes == null) {
-                _mutualSubtypes = {
-                  bestTypeSoFar: bestSoFarIndex,
-                  candidateType: candidateIndex
-                };
-              } else {
-                _mutualSubtypes[candidateType] = candidateIndex;
-              }
-            } else {
-              _mutualSubtypes = null;
-            }
-            bestSoFarIndex = candidateIndex;
-            bestSoFar = candidate;
-            bestTypeSoFar = candidateType;
-          }
-        }
-      }
-      if (bestSoFar != null) {
-        for (int candidateIndex = 0;
-            candidateIndex < members.length;
-            candidateIndex++) {
-          DartType candidateType = getMemberType(candidateIndex);
-          if (!_isMoreSpecific(bestTypeSoFar, candidateType, forSetter)) {
-            if (!shouldOverrideProblemBeOverlooked(classBuilder)) {
-              bestSoFar = null;
-              bestSoFarIndex = null;
-              bestTypeSoFar = null;
-              _mutualSubtypes = null;
-            }
-            break;
-          }
-        }
-      }
-    }
-
-    _canonicalMemberIndex = bestSoFarIndex;
-  }
-
-  /// The member within [members] type is the most specific among [members].
-  /// If `null`, the combined member signature is not defined for [members] in
-  /// [classBuilder].
-  ///
-  /// For the legacy computation, the type of this member defines the combined
-  /// member signature.
-  ///
-  /// For the nnbd computation, this is one of the members whose type define
-  /// the combined member signature, and the indices of the all members whose
-  /// type define the combined member signature are in [mutualSubtypeIndices].
-  ClassMember get canonicalClassMember =>
-      _canonicalMemberIndex != null ? members[_canonicalMemberIndex] : null;
-
-  /// The index within [members] for the member whose type is the most specific
-  /// among [members]. If `null`, the combined member signature is not defined
-  /// for [members] in [classBuilder].
-  ///
-  /// For the legacy computation, the type of this member defines the combined
-  /// member signature.
-  ///
-  /// For the nnbd computation, this is one of the members whose type define
-  /// the combined member signature, and the indices of the all members whose
-  /// type define the combined member signature are in [mutualSubtypeIndices].
-  int get classMemberIndex => _canonicalMemberIndex;
-
-  /// For the nnbd computation, the indices of the [members] with most specific
-  /// member type.
-  ///
-  /// If there is only one most specific member type, this is `null`.
-  Set<int> get mutualSubtypeIndices => _mutualSubtypes?.values?.toSet();
-
-  /// The this type of [classBuilder].
-  DartType get thisType {
-    return _thisType ??= hierarchy.coreTypes
-        .thisInterfaceType(classBuilder.cls, classBuilder.library.nonNullable);
-  }
-
-  /// Returns type of the [index]th member in [members] as inherited in
-  /// [classBuilder].
-  DartType getMemberType(int index) {
-    _memberTypes ??= new List<DartType>(members.length);
-    DartType candidateType = _memberTypes[index];
-    if (candidateType == null) {
-      ClassMember candidate = members[index];
-      Member target = candidate.getMember(hierarchy);
-      assert(target != null,
-          "No member computed for ${candidate} (${candidate.runtimeType})");
-      candidateType = _computeMemberType(thisType, target);
-      if (!classBuilder.library.isNonNullableByDefault) {
-        candidateType = legacyErasure(hierarchy.coreTypes, candidateType);
-      }
-      _memberTypes[index] = candidateType;
-    }
-    return candidateType;
-  }
-
-  /// Returns the type of the combined member signature, if defined.
-  DartType get combinedMemberSignatureType {
-    if (!_isCombinedMemberSignatureTypeComputed) {
-      _isCombinedMemberSignatureTypeComputed = true;
-      if (_canonicalMemberIndex == null) {
-        return null;
-      }
-      if (classBuilder.library.isNonNullableByDefault) {
-        _combinedMemberSignatureType = getMemberType(_canonicalMemberIndex);
-        if (_mutualSubtypes != null) {
-          _combinedMemberSignatureType =
-              norm(hierarchy.coreTypes, _combinedMemberSignatureType);
-          for (int index in _mutualSubtypes.values) {
-            if (_canonicalMemberIndex != index) {
-              _combinedMemberSignatureType = nnbdTopMerge(
-                  hierarchy.coreTypes,
-                  _combinedMemberSignatureType,
-                  norm(hierarchy.coreTypes, getMemberType(index)));
-            }
-          }
-        }
-      } else {
-        _combinedMemberSignatureType = legacyErasure(
-            hierarchy.coreTypes, getMemberType(_canonicalMemberIndex));
-      }
-    }
-    return _combinedMemberSignatureType;
-  }
-
-  /// Returns the type of the combined member signature, if defined, with
-  /// all method type parameters substituted with [typeParameters].
-  ///
-  /// This is used for inferring types on a declared member from the type of the
-  /// combined member signature.
-  DartType getCombinedSignatureTypeInContext(
-      List<TypeParameter> typeParameters) {
-    DartType type = combinedMemberSignatureType;
-    if (type == null) {
-      return null;
-    }
-    int typeParameterCount = typeParameters.length;
-    if (type is FunctionType) {
-      List<TypeParameter> signatureTypeParameters = type.typeParameters;
-      if (typeParameterCount != signatureTypeParameters.length) {
-        return null;
-      }
-      if (typeParameterCount == 0) {
-        return type;
-      }
-      List<DartType> types = new List<DartType>(typeParameterCount);
-      for (int i = 0; i < typeParameterCount; i++) {
-        types[i] = new TypeParameterType.forAlphaRenaming(
-            signatureTypeParameters[i], typeParameters[i]);
-      }
-      Substitution substitution =
-          Substitution.fromPairs(signatureTypeParameters, types);
-      for (int i = 0; i < typeParameterCount; i++) {
-        DartType typeParameterBound = typeParameters[i].bound;
-        DartType signatureTypeParameterBound =
-            substitution.substituteType(signatureTypeParameters[i].bound);
-        if (!hierarchy.types
-            .performNullabilityAwareMutualSubtypesCheck(
-                typeParameterBound, signatureTypeParameterBound)
-            .isSubtypeWhenUsingNullabilities()) {
-          return null;
-        }
-      }
-      return substitution.substituteType(type.withoutTypeParameters);
-    } else if (typeParameterCount != 0) {
-      return null;
-    }
-    return type;
-  }
-
-  DartType _computeMemberType(DartType thisType, Member member) {
-    DartType type;
-    if (member is Procedure) {
-      if (member.isGetter) {
-        type = member.getterType;
-      } else if (member.isSetter) {
-        type = member.setterType;
-      } else {
-        type = member.function
-            .computeFunctionType(member.enclosingLibrary.nonNullable);
-      }
-    } else if (member is Field) {
-      type = member.type;
-    } else {
-      unhandled("${member.runtimeType}", "$member", classBuilder.charOffset,
-          classBuilder.fileUri);
-    }
-    InterfaceType instance = hierarchy.getTypeAsInstanceOf(
-        thisType,
-        member.enclosingClass,
-        classBuilder.library.library,
-        hierarchy.coreTypes);
-    assert(
-        instance != null,
-        "No instance of $thisType as ${member.enclosingClass} found for "
-        "$member.");
-    return Substitution.fromInterfaceType(instance).substituteType(type);
-  }
-
-  bool _isMoreSpecific(DartType a, DartType b, bool forSetter) {
-    if (forSetter) {
-      return hierarchy.types
-          .isSubtypeOf(b, a, SubtypeCheckMode.withNullabilities);
-    } else {
-      return hierarchy.types
-          .isSubtypeOf(a, b, SubtypeCheckMode.withNullabilities);
-    }
-  }
-}
diff --git a/pkg/front_end/lib/src/fasta/kernel/combined_member_signature.dart b/pkg/front_end/lib/src/fasta/kernel/combined_member_signature.dart
new file mode 100644
index 0000000..96a3f02
--- /dev/null
+++ b/pkg/front_end/lib/src/fasta/kernel/combined_member_signature.dart
@@ -0,0 +1,578 @@
+// Copyright (c) 2018, 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.
+
+library fasta.class_hierarchy_builder;
+
+import 'package:kernel/ast.dart' hide MapEntry;
+
+import 'package:kernel/class_hierarchy.dart' show ClassHierarchyBase;
+
+import 'package:kernel/core_types.dart' show CoreTypes;
+
+import 'package:kernel/type_algebra.dart' show Substitution;
+import 'package:kernel/type_environment.dart';
+
+import 'package:kernel/src/legacy_erasure.dart';
+import 'package:kernel/src/nnbd_top_merge.dart';
+import 'package:kernel/src/norm.dart';
+import 'package:kernel/src/types.dart' show Types;
+
+import '../problems.dart' show unhandled;
+
+import '../source/source_class_builder.dart';
+
+import 'class_hierarchy_builder.dart';
+
+/// Class used for computing and inspecting the combined member signature for
+/// a set of overridden/inherited members.
+abstract class CombinedMemberSignatureBase<T> {
+  ClassHierarchyBase get hierarchy;
+
+  /// The target class for the combined member signature.
+  ///
+  /// The [_memberTypes] are computed in terms of each member is inherited into
+  /// [classBuilder].
+  ///
+  /// [classBuilder] is also used for determining whether the combined member
+  /// signature should be computed using nnbd or legacy semantics.
+  final SourceClassBuilder classBuilder;
+
+  /// The list of members from which the combined member signature is computed.
+  List<T> get members;
+
+  /// If `true` the combined member signature is for the setter aspect of the
+  /// members. Otherwise it is for the getter/method aspect of the members.
+  final bool forSetter;
+
+  /// The index within [members] for the member whose type is the most specific
+  /// among [members]. If `null`, the combined member signature is not defined
+  /// for [members] in [classBuilder].
+  ///
+  /// For the legacy computation, the type of this member defines the combined
+  /// member signature.
+  ///
+  /// For the nnbd computation, this is one of the members whose type define
+  /// the combined member signature, and the indices of the remaining members
+  /// are stored in [_mutualSubtypes].
+  int _canonicalMemberIndex;
+
+  /// For the nnbd computation, this maps each distinct but most specific member
+  /// type to the index of one of the [members] with that type.
+  ///
+  /// If there is only one most specific member type, this is `null`.
+  Map<DartType, int> _mutualSubtypes;
+
+  /// Cache for the types of [members] as inherited into [classBuilder].
+  List<DartType> _memberTypes;
+
+  /// Cache for the this type of [classBuilder].
+  DartType _thisType;
+
+  /// If `true` the combined member signature type has been computed.
+  ///
+  /// Note that the combined member signature type might be undefined in which
+  /// case [_combinedMemberSignatureType] is `null`.
+  bool _isCombinedMemberSignatureTypeComputed = false;
+
+  /// Cache the computed combined member signature type.
+  ///
+  /// If the combined member signature type is undefined this is set to `null`.
+  DartType _combinedMemberSignatureType;
+
+  /// Accumulated result for [neededLegacyErasure]. This is fully computed when
+  /// [combinedMemberSignatureType] has been computed.
+  bool _neededLegacyErasure = false;
+
+  /// Creates a [CombinedClassMemberSignature] whose canonical member is already
+  /// defined.
+  CombinedMemberSignatureBase.internal(
+      this.classBuilder, this._canonicalMemberIndex, this.forSetter)
+      : assert(forSetter != null);
+
+  /// Creates a [CombinedClassMemberSignature] for [members] inherited into
+  /// [classBuilder].
+  ///
+  /// If [forSetter] is `true`, contravariance of the setter types is used to
+  /// compute the most specific member type. Otherwise covariance of the getter
+  /// types or function types is used.
+  CombinedMemberSignatureBase(this.classBuilder, {this.forSetter}) {
+    assert(forSetter != null);
+    int bestSoFarIndex;
+    if (members.length == 1) {
+      bestSoFarIndex = 0;
+    } else {
+      bool isNonNullableByDefault = classBuilder.library.isNonNullableByDefault;
+
+      DartType bestTypeSoFar;
+      for (int candidateIndex = members.length - 1;
+          candidateIndex >= 0;
+          candidateIndex--) {
+        DartType candidateType = getMemberType(candidateIndex);
+        if (bestSoFarIndex == null) {
+          bestTypeSoFar = candidateType;
+          bestSoFarIndex = candidateIndex;
+        } else {
+          if (_isMoreSpecific(candidateType, bestTypeSoFar, forSetter)) {
+            if (isNonNullableByDefault &&
+                _isMoreSpecific(bestTypeSoFar, candidateType, forSetter)) {
+              if (_mutualSubtypes == null) {
+                _mutualSubtypes = {
+                  bestTypeSoFar: bestSoFarIndex,
+                  candidateType: candidateIndex
+                };
+              } else {
+                _mutualSubtypes[candidateType] = candidateIndex;
+              }
+            } else {
+              _mutualSubtypes = null;
+            }
+            bestSoFarIndex = candidateIndex;
+            bestTypeSoFar = candidateType;
+          }
+        }
+      }
+      if (bestSoFarIndex != null) {
+        for (int candidateIndex = 0;
+            candidateIndex < members.length;
+            candidateIndex++) {
+          DartType candidateType = getMemberType(candidateIndex);
+          if (!_isMoreSpecific(bestTypeSoFar, candidateType, forSetter)) {
+            if (!shouldOverrideProblemBeOverlooked(classBuilder)) {
+              bestSoFarIndex = null;
+              bestTypeSoFar = null;
+              _mutualSubtypes = null;
+            }
+            break;
+          }
+        }
+      }
+    }
+
+    _canonicalMemberIndex = bestSoFarIndex;
+  }
+
+  /// The member within [members] type is the most specific among [members].
+  /// If `null`, the combined member signature is not defined for [members] in
+  /// [classBuilder].
+  ///
+  /// For the legacy computation, the type of this member defines the combined
+  /// member signature.
+  ///
+  /// For the nnbd computation, this is one of the members whose type define
+  /// the combined member signature, and the indices of the all members whose
+  /// type define the combined member signature are in [mutualSubtypeIndices].
+  T get canonicalMember =>
+      _canonicalMemberIndex != null ? members[_canonicalMemberIndex] : null;
+
+  /// The index within [members] for the member whose type is the most specific
+  /// among [members]. If `null`, the combined member signature is not defined
+  /// for [members] in [classBuilder].
+  ///
+  /// For the legacy computation, the type of this member defines the combined
+  /// member signature.
+  ///
+  /// For the nnbd computation, this is one of the members whose type define
+  /// the combined member signature, and the indices of the all members whose
+  /// type define the combined member signature are in [mutualSubtypeIndices].
+  int get canonicalMemberIndex => _canonicalMemberIndex;
+
+  /// For the nnbd computation, the indices of the [members] with most specific
+  /// member type.
+  ///
+  /// If there is only one most specific member type, this is `null`.
+  Set<int> get mutualSubtypeIndices => _mutualSubtypes?.values?.toSet();
+
+  Member _getMember(int index);
+
+  CoreTypes get _coreTypes => hierarchy.coreTypes;
+
+  Types get _types;
+
+  /// Returns `true` if legacy erasure was needed to compute the combined
+  /// member signature type.
+  ///
+  /// Legacy erasure is considered need of if the used of it resulted in a
+  /// different type.
+  bool get neededLegacyErasure {
+    _ensureCombinedMemberSignatureType();
+    return _neededLegacyErasure;
+  }
+
+  /// The this type of [classBuilder].
+  DartType get thisType {
+    return _thisType ??= _coreTypes.thisInterfaceType(
+        classBuilder.cls, classBuilder.library.nonNullable);
+  }
+
+  /// Returns type of the [index]th member in [members] as inherited in
+  /// [classBuilder].
+  DartType getMemberType(int index) {
+    _memberTypes ??= new List<DartType>(members.length);
+    DartType candidateType = _memberTypes[index];
+    if (candidateType == null) {
+      Member target = _getMember(index);
+      assert(target != null,
+          "No member computed for index ${index} in ${members}");
+      candidateType = _computeMemberType(thisType, target);
+      if (!classBuilder.library.isNonNullableByDefault) {
+        DartType legacyErasure = rawLegacyErasure(_coreTypes, candidateType);
+        if (legacyErasure != null) {
+          _neededLegacyErasure = true;
+          candidateType = legacyErasure;
+        }
+      }
+      _memberTypes[index] = candidateType;
+    }
+    return candidateType;
+  }
+
+  void _ensureCombinedMemberSignatureType() {
+    if (!_isCombinedMemberSignatureTypeComputed) {
+      _isCombinedMemberSignatureTypeComputed = true;
+      if (_canonicalMemberIndex == null) {
+        return null;
+      }
+      if (classBuilder.library.isNonNullableByDefault) {
+        _combinedMemberSignatureType = getMemberType(_canonicalMemberIndex);
+        if (_mutualSubtypes != null) {
+          _combinedMemberSignatureType =
+              norm(_coreTypes, _combinedMemberSignatureType);
+          for (int index in _mutualSubtypes.values) {
+            if (_canonicalMemberIndex != index) {
+              _combinedMemberSignatureType = nnbdTopMerge(
+                  _coreTypes,
+                  _combinedMemberSignatureType,
+                  norm(_coreTypes, getMemberType(index)));
+            }
+          }
+        }
+      } else {
+        _combinedMemberSignatureType = getMemberType(_canonicalMemberIndex);
+      }
+    }
+  }
+
+  /// Returns the type of the combined member signature, if defined.
+  DartType get combinedMemberSignatureType {
+    _ensureCombinedMemberSignatureType();
+    return _combinedMemberSignatureType;
+  }
+
+  /// Returns the type of the combined member signature, if defined, with
+  /// all method type parameters substituted with [typeParameters].
+  ///
+  /// This is used for inferring types on a declared member from the type of the
+  /// combined member signature.
+  DartType getCombinedSignatureTypeInContext(
+      List<TypeParameter> typeParameters) {
+    DartType type = combinedMemberSignatureType;
+    if (type == null) {
+      return null;
+    }
+    int typeParameterCount = typeParameters.length;
+    if (type is FunctionType) {
+      List<TypeParameter> signatureTypeParameters = type.typeParameters;
+      if (typeParameterCount != signatureTypeParameters.length) {
+        return null;
+      }
+      if (typeParameterCount == 0) {
+        return type;
+      }
+      List<DartType> types = new List<DartType>(typeParameterCount);
+      for (int i = 0; i < typeParameterCount; i++) {
+        types[i] = new TypeParameterType.forAlphaRenaming(
+            signatureTypeParameters[i], typeParameters[i]);
+      }
+      Substitution substitution =
+          Substitution.fromPairs(signatureTypeParameters, types);
+      for (int i = 0; i < typeParameterCount; i++) {
+        DartType typeParameterBound = typeParameters[i].bound;
+        DartType signatureTypeParameterBound =
+            substitution.substituteType(signatureTypeParameters[i].bound);
+        if (!_types
+            .performNullabilityAwareMutualSubtypesCheck(
+                typeParameterBound, signatureTypeParameterBound)
+            .isSubtypeWhenUsingNullabilities()) {
+          return null;
+        }
+      }
+      return substitution.substituteType(type.withoutTypeParameters);
+    } else if (typeParameterCount != 0) {
+      return null;
+    }
+    return type;
+  }
+
+  /// Create a member signature with the [combinedMemberSignatureType] using the
+  /// [canonicalMember] as member signature origin.
+  Procedure createMemberFromSignature() {
+    if (canonicalMemberIndex == null) {
+      return null;
+    }
+    Member member = _getMember(canonicalMemberIndex);
+    if (member is Procedure) {
+      switch (member.kind) {
+        case ProcedureKind.Getter:
+          return _createGetterMemberSignature(
+              member, combinedMemberSignatureType);
+        case ProcedureKind.Setter:
+          VariableDeclaration parameter =
+              member.function.positionalParameters.first;
+          return _createSetterMemberSignature(
+              member, combinedMemberSignatureType,
+              isGenericCovariantImpl: parameter.isGenericCovariantImpl,
+              isCovariant: parameter.isCovariant,
+              parameterName: parameter.name);
+        case ProcedureKind.Method:
+        case ProcedureKind.Operator:
+          return _createMethodSignature(member, combinedMemberSignatureType);
+        case ProcedureKind.Factory:
+        default:
+          throw new UnsupportedError(
+              'Unexpected canonical member kind ${member.kind} for $member');
+      }
+    } else if (member is Field) {
+      if (forSetter) {
+        return _createSetterMemberSignature(member, combinedMemberSignatureType,
+            isGenericCovariantImpl: member.isGenericCovariantImpl,
+            isCovariant: member.isCovariant);
+      } else {
+        return _createGetterMemberSignature(
+            member, combinedMemberSignatureType);
+      }
+    } else {
+      throw new UnsupportedError(
+          'Unexpected canonical member $member (${member.runtimeType})');
+    }
+  }
+
+  /// Creates a getter member signature for [member] with the given
+  /// [type].
+  Member _createGetterMemberSignature(Member member, DartType type) {
+    Class enclosingClass = classBuilder.cls;
+    Procedure referenceFrom;
+    if (classBuilder.referencesFromIndexed != null) {
+      referenceFrom = classBuilder.referencesFromIndexed
+          .lookupProcedureNotSetter(member.name.text);
+    }
+    Uri fileUri = member.fileUri;
+    int startFileOffset =
+        member is Procedure ? member.startFileOffset : member.fileOffset;
+    int fileOffset = member.fileOffset;
+    return new Procedure(member.name, ProcedureKind.Getter,
+        new FunctionNode(null, returnType: type),
+        isAbstract: true,
+        isMemberSignature: true,
+        fileUri: fileUri,
+        memberSignatureOrigin: member.memberSignatureOrigin ?? member,
+        reference: referenceFrom?.reference)
+      ..startFileOffset = startFileOffset
+      ..fileOffset = fileOffset
+      ..parent = enclosingClass;
+  }
+
+  /// Creates a setter member signature for [member] with the given
+  /// [type]. The flags of parameter is set according to [isCovariant] and
+  /// [isGenericCovariantImpl] and the [parameterName] is used, if provided.
+  Member _createSetterMemberSignature(Member member, DartType type,
+      {bool isCovariant, bool isGenericCovariantImpl, String parameterName}) {
+    assert(isCovariant != null);
+    assert(isGenericCovariantImpl != null);
+    Class enclosingClass = classBuilder.cls;
+    Procedure referenceFrom;
+    if (classBuilder.referencesFromIndexed != null) {
+      referenceFrom = classBuilder.referencesFromIndexed
+          .lookupProcedureSetter(member.name.text);
+    }
+    Uri fileUri = member.fileUri;
+    int startFileOffset =
+        member is Procedure ? member.startFileOffset : member.fileOffset;
+    int fileOffset = member.fileOffset;
+    return new Procedure(
+        member.name,
+        ProcedureKind.Setter,
+        new FunctionNode(null,
+            returnType: const VoidType(),
+            positionalParameters: [
+              new VariableDeclaration(parameterName ?? 'value',
+                  type: type, isCovariant: isCovariant)
+                ..isGenericCovariantImpl = isGenericCovariantImpl
+            ]),
+        isAbstract: true,
+        isMemberSignature: true,
+        fileUri: fileUri,
+        memberSignatureOrigin: member.memberSignatureOrigin ?? member,
+        reference: referenceFrom?.reference)
+      ..startFileOffset = startFileOffset
+      ..fileOffset = fileOffset
+      ..parent = enclosingClass;
+  }
+
+  Member _createMethodSignature(
+      Procedure procedure, FunctionType functionType) {
+    Class enclosingClass = classBuilder.cls;
+    Procedure referenceFrom;
+    if (classBuilder.referencesFromIndexed != null) {
+      referenceFrom = classBuilder.referencesFromIndexed
+          .lookupProcedureNotSetter(procedure.name.text);
+    }
+    Uri fileUri = procedure.fileUri;
+    int startFileOffset = procedure.startFileOffset;
+    int fileOffset = procedure.fileOffset;
+    FunctionNode function = procedure.function;
+    List<VariableDeclaration> positionalParameters = [];
+    for (int i = 0; i < function.positionalParameters.length; i++) {
+      VariableDeclaration parameter = function.positionalParameters[i];
+      DartType parameterType = functionType.positionalParameters[i];
+      if (i == 0 && procedure == hierarchy.coreTypes.objectEquals) {
+        // In legacy code we special case `Object.==` to infer `dynamic`
+        // instead `Object!`.
+        parameterType = const DynamicType();
+      }
+      positionalParameters.add(new VariableDeclaration(parameter.name,
+          type: parameterType, isCovariant: parameter.isCovariant)
+        ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
+    }
+    List<VariableDeclaration> namedParameters = [];
+    int namedParameterCount = function.namedParameters.length;
+    if (namedParameterCount == 1) {
+      NamedType namedType = functionType.namedParameters.first;
+      VariableDeclaration parameter = function.namedParameters.first;
+      namedParameters.add(new VariableDeclaration(parameter.name,
+          type: namedType.type, isCovariant: parameter.isCovariant)
+        ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
+    } else if (namedParameterCount > 1) {
+      Map<String, DartType> namedTypes = {};
+      for (NamedType namedType in functionType.namedParameters) {
+        namedTypes[namedType.name] = namedType.type;
+      }
+      for (int i = 0; i < namedParameterCount; i++) {
+        VariableDeclaration parameter = function.namedParameters[i];
+        DartType parameterType = namedTypes[parameter.name];
+        namedParameters.add(new VariableDeclaration(parameter.name,
+            type: parameterType, isCovariant: parameter.isCovariant)
+          ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
+      }
+    }
+    return new Procedure(
+        procedure.name,
+        procedure.kind,
+        new FunctionNode(null,
+            typeParameters: functionType.typeParameters,
+            returnType: functionType.returnType,
+            positionalParameters: positionalParameters,
+            namedParameters: namedParameters,
+            requiredParameterCount: function.requiredParameterCount),
+        isAbstract: true,
+        isMemberSignature: true,
+        fileUri: fileUri,
+        memberSignatureOrigin: procedure.memberSignatureOrigin ?? procedure,
+        reference: referenceFrom?.reference)
+      ..startFileOffset = startFileOffset
+      ..fileOffset = fileOffset
+      ..parent = enclosingClass;
+  }
+
+  DartType _computeMemberType(DartType thisType, Member member) {
+    DartType type;
+    if (member is Procedure) {
+      if (member.isGetter) {
+        type = member.getterType;
+      } else if (member.isSetter) {
+        type = member.setterType;
+      } else {
+        type = member.function
+            .computeFunctionType(classBuilder.cls.enclosingLibrary.nonNullable);
+      }
+    } else if (member is Field) {
+      type = member.type;
+    } else {
+      unhandled("${member.runtimeType}", "$member", classBuilder.charOffset,
+          classBuilder.fileUri);
+    }
+    if (member.enclosingClass.typeParameters.isEmpty) {
+      return type;
+    }
+    InterfaceType instance = hierarchy.getTypeAsInstanceOf(
+        thisType,
+        member.enclosingClass,
+        classBuilder.library.library,
+        hierarchy.coreTypes);
+    assert(
+        instance != null,
+        "No instance of $thisType as ${member.enclosingClass} found for "
+        "$member.");
+    return Substitution.fromInterfaceType(instance).substituteType(type);
+  }
+
+  bool _isMoreSpecific(DartType a, DartType b, bool forSetter) {
+    if (forSetter) {
+      return _types.isSubtypeOf(b, a, SubtypeCheckMode.withNullabilities);
+    } else {
+      return _types.isSubtypeOf(a, b, SubtypeCheckMode.withNullabilities);
+    }
+  }
+}
+
+/// Class used for computing and inspecting the combined member signature for
+/// a set of overridden/inherited [ClassMember]s.
+class CombinedClassMemberSignature
+    extends CombinedMemberSignatureBase<ClassMember> {
+  /// The class hierarchy builder used for building this class.
+  final ClassHierarchyBuilder hierarchy;
+
+  /// The list of the members inherited into or overridden in [classBuilder].
+  final List<ClassMember> members;
+
+  /// Creates a [CombinedClassMemberSignature] whose canonical member is already
+  /// defined.
+  CombinedClassMemberSignature.internal(this.hierarchy,
+      SourceClassBuilder classBuilder, int canonicalMemberIndex, this.members,
+      {bool forSetter})
+      : super.internal(classBuilder, canonicalMemberIndex, forSetter);
+
+  /// Creates a [CombinedClassMemberSignature] for [members] inherited into
+  /// [classBuilder].
+  ///
+  /// If [forSetter] is `true`, contravariance of the setter types is used to
+  /// compute the most specific member type. Otherwise covariance of the getter
+  /// types or function types is used.
+  CombinedClassMemberSignature(
+      this.hierarchy, SourceClassBuilder classBuilder, this.members,
+      {bool forSetter})
+      : super(classBuilder, forSetter: forSetter);
+
+  Types get _types => hierarchy.types;
+
+  Member _getMember(int index) {
+    ClassMember candidate = members[index];
+    Member target = candidate.getMember(hierarchy);
+    assert(target != null,
+        "No member computed for ${candidate} (${candidate.runtimeType})");
+    return target;
+  }
+}
+
+/// Class used for computing and inspecting the combined member signature for
+/// a set of overridden/inherited [Member]s.
+class CombinedMemberSignatureBuilder
+    extends CombinedMemberSignatureBase<Member> {
+  @override
+  final ClassHierarchyBase hierarchy;
+
+  @override
+  final Types _types;
+
+  @override
+  final List<Member> members;
+
+  CombinedMemberSignatureBuilder(
+      this.hierarchy, SourceClassBuilder classBuilder, this.members,
+      {bool forSetter})
+      : _types = new Types(hierarchy),
+        super(classBuilder, forSetter: forSetter);
+
+  @override
+  Member _getMember(int index) => members[index];
+}
diff --git a/pkg/front_end/lib/src/fasta/kernel/forwarding_node.dart b/pkg/front_end/lib/src/fasta/kernel/forwarding_node.dart
index 08a6f34..21dd2f3 100644
--- a/pkg/front_end/lib/src/fasta/kernel/forwarding_node.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/forwarding_node.dart
@@ -11,12 +11,9 @@
         Expression,
         Field,
         FunctionNode,
-        FunctionType,
         Member,
         Name,
         NamedExpression,
-        NamedType,
-        Nullability,
         Procedure,
         ProcedureKind,
         ReturnStatement,
@@ -48,6 +45,7 @@
 import "../type_inference/type_inferrer.dart" show getNamedFormal;
 
 import 'class_hierarchy_builder.dart';
+import 'combined_member_signature.dart';
 
 class ForwardingNode {
   ClassHierarchyBuilder get hierarchy => _combinedMemberSignature.hierarchy;
@@ -56,13 +54,13 @@
 
   // TODO(johnniwinther): Use [_combinedMemberSignature] more directly in
   // the forwarding node computation.
-  final CombinedMemberSignature _combinedMemberSignature;
+  final CombinedClassMemberSignature _combinedMemberSignature;
 
   ClassMember get combinedMemberSignatureResult =>
-      _combinedMemberSignature.canonicalClassMember;
+      _combinedMemberSignature.canonicalMember;
 
   /// The index of [combinedMemberSignatureResult] in [_candidates].
-  int get _combinedMemberIndex => _combinedMemberSignature.classMemberIndex;
+  int get _combinedMemberIndex => _combinedMemberSignature.canonicalMemberIndex;
 
   final ProcedureKind kind;
 
@@ -84,203 +82,6 @@
   /// forwarding stubs if necessary.
   Member finalize() => _computeCovarianceFixes();
 
-  /// Creates a getter member signature for [interfaceMember] with the given
-  /// [type].
-  Member _createGetterMemberSignature(Member interfaceMember, DartType type) {
-    Procedure referenceFrom;
-    if (classBuilder.referencesFromIndexed != null) {
-      referenceFrom = classBuilder.referencesFromIndexed
-          .lookupProcedureNotSetter(name.text);
-    }
-    return new Procedure(name, kind, new FunctionNode(null, returnType: type),
-        isAbstract: true,
-        isMemberSignature: true,
-        fileUri: enclosingClass.fileUri,
-        memberSignatureOrigin: interfaceMember,
-        reference: referenceFrom?.reference)
-      ..startFileOffset = enclosingClass.fileOffset
-      ..fileOffset = enclosingClass.fileOffset
-      ..parent = enclosingClass;
-  }
-
-  /// Creates a setter member signature for [interfaceMember] with the given
-  /// [type]. The flags of parameter is set according to [isCovariant] and
-  /// [isGenericCovariantImpl] and the [parameterName] is used, if provided.
-  Member _createSetterMemberSignature(Member interfaceMember, DartType type,
-      {bool isCovariant, bool isGenericCovariantImpl, String parameterName}) {
-    assert(isCovariant != null);
-    assert(isGenericCovariantImpl != null);
-    Procedure referenceFrom;
-    if (classBuilder.referencesFromIndexed != null) {
-      referenceFrom =
-          classBuilder.referencesFromIndexed.lookupProcedureSetter(name.text);
-    }
-    return new Procedure(
-        name,
-        kind,
-        new FunctionNode(null,
-            returnType: const VoidType(),
-            positionalParameters: [
-              new VariableDeclaration(parameterName ?? '_',
-                  type: type, isCovariant: isCovariant)
-                ..isGenericCovariantImpl = isGenericCovariantImpl
-            ]),
-        isAbstract: true,
-        isMemberSignature: true,
-        fileUri: enclosingClass.fileUri,
-        memberSignatureOrigin: interfaceMember,
-        reference: referenceFrom?.reference)
-      ..startFileOffset = enclosingClass.fileOffset
-      ..fileOffset = enclosingClass.fileOffset
-      ..parent = enclosingClass;
-  }
-
-  /// Creates a legacy member signature for the field [interfaceMember] if the
-  /// type of [interfaceMember] contains non-legacy nullabilities.
-  Member _createLegacyMemberSignatureForField(Field interfaceMember) {
-    DartType type = interfaceMember.type;
-    if (interfaceMember.enclosingClass.typeParameters.isNotEmpty) {
-      Substitution substitution =
-          _substitutionFor(null, interfaceMember, enclosingClass);
-      type = substitution.substituteType(type);
-    }
-    DartType legacyType = rawLegacyErasure(hierarchy.coreTypes, type);
-    if (legacyType == null) {
-      return interfaceMember;
-    } else {
-      // We base the decision to add a member signature on whether the legacy
-      // erasure of the declared type is different from the declared type, i.e.
-      // whether the declared type contained non-legacy nullabilities.
-      //
-      // This is slightly different from checking whether the legacy erasure of
-      // the inherited type is different from the
-      if (kind == ProcedureKind.Getter) {
-        return _createGetterMemberSignature(interfaceMember, legacyType);
-      } else {
-        assert(kind == ProcedureKind.Setter);
-        return _createSetterMemberSignature(interfaceMember, legacyType,
-            isCovariant: interfaceMember.isCovariant,
-            isGenericCovariantImpl: interfaceMember.isGenericCovariantImpl);
-      }
-    }
-  }
-
-  /// Creates a legacy member signature for procedure [interfaceMember] if the
-  /// type of [interfaceMember] contains non-legacy nullabilities.
-  Member _createLegacyMemberSignatureForProcedure(Procedure interfaceMember) {
-    if (interfaceMember.kind == ProcedureKind.Getter) {
-      DartType type = interfaceMember.getterType;
-      if (interfaceMember.enclosingClass.typeParameters.isNotEmpty) {
-        Substitution substitution =
-            _substitutionFor(null, interfaceMember, enclosingClass);
-        type = substitution.substituteType(type);
-      }
-      DartType legacyType = rawLegacyErasure(hierarchy.coreTypes, type);
-      if (legacyType == null) {
-        return interfaceMember;
-      } else {
-        return _createGetterMemberSignature(interfaceMember, legacyType);
-      }
-    } else if (interfaceMember.kind == ProcedureKind.Setter) {
-      DartType type = interfaceMember.setterType;
-      if (interfaceMember.enclosingClass.typeParameters.isNotEmpty) {
-        Substitution substitution =
-            _substitutionFor(null, interfaceMember, enclosingClass);
-        type = substitution.substituteType(type);
-      }
-      DartType legacyType = rawLegacyErasure(hierarchy.coreTypes, type);
-      if (legacyType == null) {
-        return interfaceMember;
-      } else {
-        VariableDeclaration parameter =
-            interfaceMember.function.positionalParameters.first;
-        return _createSetterMemberSignature(interfaceMember, legacyType,
-            isCovariant: parameter.isCovariant,
-            isGenericCovariantImpl: parameter.isGenericCovariantImpl,
-            parameterName: parameter.name);
-      }
-    } else {
-      FunctionNode function = interfaceMember.function;
-      FunctionType type = function.computeFunctionType(Nullability.legacy);
-      if (interfaceMember.enclosingClass.typeParameters.isNotEmpty) {
-        Substitution substitution =
-            _substitutionFor(null, interfaceMember, enclosingClass);
-        type = substitution.substituteType(type);
-      }
-      FunctionType legacyType = rawLegacyErasure(hierarchy.coreTypes, type);
-      if (legacyType == null) {
-        return interfaceMember;
-      }
-      Procedure referenceFrom;
-      if (classBuilder.referencesFromIndexed != null) {
-        referenceFrom = classBuilder.referencesFromIndexed
-            .lookupProcedureNotSetter(name.text);
-      }
-      List<VariableDeclaration> positionalParameters = [];
-      for (int i = 0; i < function.positionalParameters.length; i++) {
-        VariableDeclaration parameter = function.positionalParameters[i];
-        DartType parameterType = legacyType.positionalParameters[i];
-        if (i == 0 && interfaceMember == hierarchy.coreTypes.objectEquals) {
-          // In legacy code we special case `Object.==` to infer `dynamic`
-          // instead `Object!`.
-          parameterType = const DynamicType();
-        }
-        positionalParameters.add(new VariableDeclaration(parameter.name,
-            type: parameterType, isCovariant: parameter.isCovariant)
-          ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
-      }
-      List<VariableDeclaration> namedParameters = [];
-      int namedParameterCount = function.namedParameters.length;
-      if (namedParameterCount == 1) {
-        NamedType namedType = legacyType.namedParameters.first;
-        VariableDeclaration parameter = function.namedParameters.first;
-        namedParameters.add(new VariableDeclaration(parameter.name,
-            type: namedType.type, isCovariant: parameter.isCovariant)
-          ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
-      } else if (namedParameterCount > 1) {
-        Map<String, DartType> namedTypes = {};
-        for (NamedType namedType in legacyType.namedParameters) {
-          namedTypes[namedType.name] = namedType.type;
-        }
-        for (int i = 0; i < namedParameterCount; i++) {
-          VariableDeclaration parameter = function.namedParameters[i];
-          DartType parameterType = namedTypes[parameter.name];
-          namedParameters.add(new VariableDeclaration(parameter.name,
-              type: parameterType, isCovariant: parameter.isCovariant)
-            ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
-        }
-      }
-      return new Procedure(
-          name,
-          kind,
-          new FunctionNode(null,
-              typeParameters: legacyType.typeParameters,
-              returnType: legacyType.returnType,
-              positionalParameters: positionalParameters,
-              namedParameters: namedParameters,
-              requiredParameterCount: function.requiredParameterCount),
-          isAbstract: true,
-          isMemberSignature: true,
-          fileUri: enclosingClass.fileUri,
-          memberSignatureOrigin: interfaceMember,
-          reference: referenceFrom?.reference)
-        ..startFileOffset = enclosingClass.fileOffset
-        ..fileOffset = enclosingClass.fileOffset
-        ..parent = enclosingClass;
-    }
-  }
-
-  /// Creates a legacy member signature for [interfaceMember] if the type of
-  /// [interfaceMember] contains non-legacy nullabilities.
-  Member _createLegacyMemberSignature(Member interfaceMember) {
-    if (interfaceMember is Field) {
-      return _createLegacyMemberSignatureForField(interfaceMember);
-    } else {
-      assert(interfaceMember is Procedure);
-      return _createLegacyMemberSignatureForProcedure(interfaceMember);
-    }
-  }
-
   /// Tag the parameters of [interfaceMember] that need type checks
   ///
   /// Parameters can need type checks for calls coming from statically typed
@@ -296,10 +97,8 @@
     if (_candidates.length == 1) {
       // Covariance can only come from [interfaceMember] so we never need a
       // forwarding stub.
-      if (interfaceMember.isNonNullableByDefault &&
-          !classBuilder.library.isNonNullableByDefault) {
-        // Create a member signature with the legacy erasure type.
-        return _createLegacyMemberSignature(interfaceMember);
+      if (_combinedMemberSignature.neededLegacyErasure) {
+        return _combinedMemberSignature.createMemberFromSignature();
       } else {
         // Nothing to do.
         return interfaceMember;
diff --git a/pkg/front_end/lib/src/fasta/kernel/transform_set_literals.dart b/pkg/front_end/lib/src/fasta/kernel/transform_set_literals.dart
index 7b3a8de..ea13c05 100644
--- a/pkg/front_end/lib/src/fasta/kernel/transform_set_literals.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/transform_set_literals.dart
@@ -9,14 +9,17 @@
 import 'package:kernel/ast.dart'
     show
         Arguments,
+        Block,
+        BlockExpression,
         Expression,
+        ExpressionStatement,
         InterfaceType,
-        Let,
         Library,
         MethodInvocation,
         Name,
         Procedure,
         SetLiteral,
+        Statement,
         StaticInvocation,
         TreeNode,
         VariableDeclaration,
@@ -60,26 +63,31 @@
   TreeNode visitSetLiteral(SetLiteral node) {
     if (node.isConst) return node;
 
-    // Outermost declaration of let chain: Set<E> setVar = new Set<E>();
+    // Create the set: Set<E> setVar = new Set<E>();
     VariableDeclaration setVar = new VariableDeclaration.forValue(
         new StaticInvocation(
             setFactory, new Arguments([], types: [node.typeArgument])),
         type: new InterfaceType(coreTypes.setClass, _currentLibrary.nonNullable,
             [node.typeArgument]));
-    // Innermost body of let chain: setVar
-    Expression setExp = new VariableGet(setVar);
-    for (int i = node.expressions.length - 1; i >= 0; i--) {
-      // let _ = setVar.add(expression) in rest
+
+    // Now create a list of all statements needed.
+    List<Statement> statements = [setVar];
+    for (int i = 0; i < node.expressions.length; i++) {
       Expression entry = node.expressions[i].accept<TreeNode>(this);
-      setExp = new Let(
-          new VariableDeclaration.forValue(new MethodInvocation(
-              new VariableGet(setVar),
-              new Name("add"),
-              new Arguments([entry]),
-              addMethod)),
-          setExp);
+      MethodInvocation methodInvocation = new MethodInvocation(
+          new VariableGet(setVar),
+          new Name("add"),
+          new Arguments([entry]),
+          addMethod)
+        ..fileOffset = entry.fileOffset;
+      statements.add(new ExpressionStatement(methodInvocation)
+        ..fileOffset = methodInvocation.fileOffset);
     }
-    return new Let(setVar, setExp);
+
+    // Finally, return a BlockExpression with the statements, having the value
+    // of the (now created) set.
+    return new BlockExpression(new Block(statements), new VariableGet(setVar))
+      ..fileOffset = node.fileOffset;
   }
 
   void enterLibrary(Library library) {
diff --git a/pkg/front_end/lib/src/fasta/source/source_class_builder.dart b/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
index 80f035d..8daa616 100644
--- a/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
@@ -6,14 +6,11 @@
 
 import 'package:kernel/ast.dart' hide MapEntry;
 import 'package:kernel/class_hierarchy.dart' show ClassHierarchy;
-import 'package:kernel/clone.dart' show CloneProcedureWithoutBody;
 import 'package:kernel/reference_from_index.dart' show IndexedClass;
 import 'package:kernel/src/bounds_checks.dart';
 import 'package:kernel/src/legacy_erasure.dart';
 import 'package:kernel/src/types.dart' show Types;
 import 'package:kernel/type_algebra.dart' show Substitution;
-import 'package:kernel/type_algebra.dart' as type_algebra
-    show getSubstitutionMap;
 import 'package:kernel/type_environment.dart';
 
 import '../builder/builder.dart';
@@ -38,6 +35,8 @@
 
 import '../fasta_codes.dart';
 
+import '../kernel/combined_member_signature.dart'
+    show CombinedMemberSignatureBuilder;
 import '../kernel/kernel_builder.dart' show compareProcedures;
 import '../kernel/kernel_target.dart' show KernelTarget;
 import '../kernel/redirecting_factory_body.dart' show RedirectingFactoryBody;
@@ -634,103 +633,12 @@
     return charOffset.compareTo(other.charOffset);
   }
 
-  void addNoSuchMethodForwarderForProcedure(Member noSuchMethod,
-      KernelTarget target, Procedure procedure, ClassHierarchy hierarchy) {
-    Procedure referenceFrom;
-    if (referencesFromIndexed != null) {
-      if (procedure.isSetter) {
-        referenceFrom =
-            referencesFromIndexed.lookupProcedureSetter(procedure.name.text);
-      } else {
-        referenceFrom =
-            referencesFromIndexed.lookupProcedureNotSetter(procedure.name.text);
-      }
-    }
-
-    CloneProcedureWithoutBody cloner = new CloneProcedureWithoutBody(
-        typeSubstitution: type_algebra.getSubstitutionMap(
-            hierarchy.getClassAsInstanceOf(cls, procedure.enclosingClass)),
-        cloneAnnotations: false);
-    Procedure cloned = cloner.cloneProcedure(procedure, referenceFrom)
-      ..isExternal = false;
-    transformProcedureToNoSuchMethodForwarder(noSuchMethod, target, cloned);
-    cls.procedures.add(cloned);
-    cloned.parent = cls;
-
-    library.forwardersOrigins.add(cloned);
-    library.forwardersOrigins.add(procedure);
-  }
-
-  void addNoSuchMethodForwarderGetterForField(
-      Field field, Member noSuchMethod, KernelTarget target) {
-    ClassHierarchy hierarchy = target.loader.hierarchy;
-    Substitution substitution = Substitution.fromSupertype(
-        hierarchy.getClassAsInstanceOf(cls, field.enclosingClass));
-
-    Procedure referenceFrom;
-    if (referencesFromIndexed != null) {
-      referenceFrom =
-          referencesFromIndexed.lookupProcedureNotSetter(field.name.text);
-    }
-    Procedure getter = new Procedure(
-        field.name,
-        ProcedureKind.Getter,
-        new FunctionNode(null,
-            typeParameters: <TypeParameter>[],
-            positionalParameters: <VariableDeclaration>[],
-            namedParameters: <VariableDeclaration>[],
-            requiredParameterCount: 0,
-            returnType: substitution.substituteType(field.type)),
-        fileUri: field.fileUri,
-        reference: referenceFrom?.reference)
-      ..fileOffset = field.fileOffset
-      ..isNonNullableByDefault = cls.enclosingLibrary.isNonNullableByDefault;
-    transformProcedureToNoSuchMethodForwarder(noSuchMethod, target, getter);
-    cls.procedures.add(getter);
-    getter.parent = cls;
-  }
-
-  void addNoSuchMethodForwarderSetterForField(
-      Field field, Member noSuchMethod, KernelTarget target) {
-    ClassHierarchy hierarchy = target.loader.hierarchy;
-    Substitution substitution = Substitution.fromSupertype(
-        hierarchy.getClassAsInstanceOf(cls, field.enclosingClass));
-
-    Procedure referenceFrom;
-    if (referencesFromIndexed != null) {
-      referenceFrom =
-          referencesFromIndexed.lookupProcedureSetter(field.name.text);
-    }
-
-    Procedure setter = new Procedure(
-        field.name,
-        ProcedureKind.Setter,
-        new FunctionNode(null,
-            typeParameters: <TypeParameter>[],
-            positionalParameters: <VariableDeclaration>[
-              new VariableDeclaration("value",
-                  type: substitution.substituteType(field.type))
-            ],
-            namedParameters: <VariableDeclaration>[],
-            requiredParameterCount: 1,
-            returnType: const VoidType()),
-        fileUri: field.fileUri,
-        reference: referenceFrom?.reference)
-      ..fileOffset = field.fileOffset
-      ..isNonNullableByDefault = cls.enclosingLibrary.isNonNullableByDefault;
-    transformProcedureToNoSuchMethodForwarder(noSuchMethod, target, setter);
-    cls.procedures.add(setter);
-    setter.parent = cls;
-  }
-
   bool _addMissingNoSuchMethodForwarders(
       KernelTarget target, Set<Member> existingForwarders,
       {bool forSetters}) {
     assert(forSetters != null);
 
     ClassHierarchy hierarchy = target.loader.hierarchy;
-    TypeEnvironment typeEnvironment =
-        target.loader.typeInferenceEngine.typeSchemaEnvironment;
 
     List<Member> allMembers =
         hierarchy.getInterfaceMembers(cls, setters: forSetters);
@@ -756,99 +664,47 @@
       (sameNameMembers[member.name] ??= []).add(member);
     }
     for (Name name in sameNameMembers.keys) {
-      List<Member> members = sameNameMembers[name];
-      assert(members.isNotEmpty);
-      List<DartType> memberTypes = [];
-
-      // The most specific member has the type that is subtype of the types of
-      // all other members.
-      Member bestSoFar = members.first;
-      DartType bestSoFarType =
-          forSetters ? bestSoFar.setterType : bestSoFar.getterType;
-      Supertype supertype =
-          hierarchy.getClassAsInstanceOf(cls, bestSoFar.enclosingClass);
-      assert(
-          supertype != null,
-          "No supertype of enclosing class ${bestSoFar.enclosingClass} for "
-          "$bestSoFar found for $cls.");
-      bestSoFarType =
-          Substitution.fromSupertype(supertype).substituteType(bestSoFarType);
-      for (int i = 1; i < members.length; ++i) {
-        Member candidate = members[i];
-        DartType candidateType =
-            forSetters ? candidate.setterType : candidate.getterType;
-        Supertype supertype =
-            hierarchy.getClassAsInstanceOf(cls, candidate.enclosingClass);
-        assert(
-            supertype != null,
-            "No supertype of enclosing class ${candidate.enclosingClass} for "
-            "$candidate found for $cls.");
-        Substitution substitution = Substitution.fromSupertype(supertype);
-        candidateType = substitution.substituteType(candidateType);
-        memberTypes.add(candidateType);
-        bool isMoreSpecific = forSetters
-            ? typeEnvironment.isSubtypeOf(bestSoFarType, candidateType,
-                SubtypeCheckMode.withNullabilities)
-            : typeEnvironment.isSubtypeOf(candidateType, bestSoFarType,
-                SubtypeCheckMode.withNullabilities);
-        if (isMoreSpecific) {
-          bestSoFar = candidate;
-          bestSoFarType = candidateType;
-        }
-      }
-      // Since isSubtypeOf isn't a linear order on types, we need to check once
-      // again that the found member is indeed the most specific one.
-      bool isActuallyBestSoFar = true;
-      for (DartType memberType in memberTypes) {
-        bool isMoreSpecific = forSetters
-            ? typeEnvironment.isSubtypeOf(
-                memberType, bestSoFarType, SubtypeCheckMode.withNullabilities)
-            : typeEnvironment.isSubtypeOf(
-                bestSoFarType, memberType, SubtypeCheckMode.withNullabilities);
-        if (!isMoreSpecific) {
-          isActuallyBestSoFar = false;
-          break;
-        }
-      }
-      if (!isActuallyBestSoFar) {
-        // It's a member conflict that is reported elsewhere.
-      } else {
-        Member member = bestSoFar;
-
+      Member declaredMember =
+          ClassHierarchy.findMemberByName(declaredMembers, name);
+      if (declaredMember != null && declaredMember.enclosingClass == cls) {
+        // If there is a member in this class then it already has the
+        // defining type; either because it was declared in this class or
+        // because it was synthesized to have the combined signature type.
         if (_isForwarderRequired(
-                clsHasUserDefinedNoSuchMethod, member, cls, concreteMembers,
+                clsHasUserDefinedNoSuchMethod, name, cls, concreteMembers,
+                isPatch: declaredMember.fileUri !=
+                    declaredMember.enclosingClass.fileUri) &&
+            !existingForwarders.contains(declaredMember)) {
+          // If there is a member declared in this class, then it's
+          // abstract and can be transformed into a noSuchMethod forwarder.
+          _transformProcedureToNoSuchMethodForwarder(
+              noSuchMethod, target, declaredMember);
+          changed = true;
+        }
+      } else {
+        List<Member> members = sameNameMembers[name];
+        assert(members.isNotEmpty);
+        CombinedMemberSignatureBuilder combinedMemberSignatureBuilder =
+            new CombinedMemberSignatureBuilder(hierarchy, this, members,
+                forSetter: forSetters);
+        Member member = combinedMemberSignatureBuilder.canonicalMember;
+        if (member != null &&
+            _isForwarderRequired(
+                clsHasUserDefinedNoSuchMethod, name, cls, concreteMembers,
                 isPatch: member.fileUri != member.enclosingClass.fileUri) &&
             !existingForwarders.contains(member)) {
+          Procedure memberSignature =
+              combinedMemberSignatureBuilder.createMemberFromSignature();
+          _transformProcedureToNoSuchMethodForwarder(
+              noSuchMethod, target, memberSignature);
+          cls.procedures.add(memberSignature);
+          memberSignature.parent = cls;
+
           if (member is Procedure) {
-            // If there's a declared member with such name, then it's abstract
-            // -- transform it into a noSuchMethod forwarder.
-            if (ClassHierarchy.findMemberByName(declaredMembers, member.name) !=
-                null) {
-              transformProcedureToNoSuchMethodForwarder(
-                  noSuchMethod, target, member);
-            } else {
-              addNoSuchMethodForwarderForProcedure(
-                  noSuchMethod, target, member, hierarchy);
-            }
-            changed = true;
-          } else if (member is Field) {
-            // Current class isn't abstract, so it can't have an abstract field
-            // with the same name -- just insert the forwarder.
-            if (forSetters) {
-              addNoSuchMethodForwarderSetterForField(
-                  member, noSuchMethod, target);
-            } else {
-              addNoSuchMethodForwarderGetterForField(
-                  member, noSuchMethod, target);
-            }
-            changed = true;
-          } else {
-            return unhandled(
-                "${member.runtimeType}",
-                "addNoSuchMethodForwarders",
-                cls.fileOffset,
-                cls.enclosingLibrary.fileUri);
+            library.forwardersOrigins.add(memberSignature);
+            library.forwardersOrigins.add(member);
           }
+          changed = true;
         }
       }
     }
@@ -881,8 +737,8 @@
               hierarchy.getDispatchTargets(nearestConcreteSuperclass);
           for (Member member
               in hierarchy.getInterfaceMembers(nearestConcreteSuperclass)) {
-            if (_isForwarderRequired(superHasUserDefinedNoSuchMethod, member,
-                nearestConcreteSuperclass, concrete,
+            if (_isForwarderRequired(superHasUserDefinedNoSuchMethod,
+                member.name, nearestConcreteSuperclass, concrete,
                 isPatch: member.fileUri != member.enclosingClass.fileUri)) {
               existingForwarders.add(member);
             }
@@ -894,8 +750,9 @@
               .getDispatchTargets(nearestConcreteSuperclass, setters: true);
           for (Member member in hierarchy
               .getInterfaceMembers(nearestConcreteSuperclass, setters: true)) {
-            if (_isForwarderRequired(superHasUserDefinedNoSuchMethod, member,
-                nearestConcreteSuperclass, concreteSetters)) {
+            if (_isForwarderRequired(superHasUserDefinedNoSuchMethod,
+                member.name, nearestConcreteSuperclass, concreteSetters,
+                isPatch: member.fileUri != member.enclosingClass.fileUri)) {
               existingSetterForwarders.add(member);
             }
           }
@@ -920,8 +777,11 @@
   }
 
   /// Tells if a noSuchMethod forwarder is required for [member] in [cls].
-  bool _isForwarderRequired(bool hasUserDefinedNoSuchMethod, Member member,
+  bool _isForwarderRequired(bool hasUserDefinedNoSuchMethod, Name name,
       Class cls, List<Member> concreteMembers,
+      // TODO(johnniwinther): This is ill-defined. Either we should only allow
+      // injected members to be private or we need a flag on members that should
+      // be propagated through member signatures.
       {bool isPatch = false}) {
     // A noSuchMethod forwarder is allowed for an abstract member if the class
     // has a user-defined noSuchMethod or if the member is private and is
@@ -929,17 +789,57 @@
     // to be visible only to patches, so they are treated as if they were from
     // another library.
     bool isForwarderAllowed = hasUserDefinedNoSuchMethod ||
-        (member.name.isPrivate &&
-            cls.enclosingLibrary.compareTo(member.enclosingLibrary) != 0) ||
-        (member.name.isPrivate && isPatch);
+        (name.isPrivate && (name.library != cls.enclosingLibrary || isPatch));
     // A noSuchMethod forwarder is required if it's allowed and if there's no
     // concrete implementation or a forwarder already.
     bool isForwarderRequired = isForwarderAllowed &&
-        ClassHierarchy.findMemberByName(concreteMembers, member.name) == null;
+        ClassHierarchy.findMemberByName(concreteMembers, name) == null;
     return isForwarderRequired;
   }
 
-  void addRedirectingConstructor(ProcedureBuilder constructorBuilder,
+  void _transformProcedureToNoSuchMethodForwarder(
+      Member noSuchMethodInterface, KernelTarget target, Procedure procedure) {
+    String prefix = procedure.isGetter
+        ? 'get:'
+        : procedure.isSetter
+            ? 'set:'
+            : '';
+    String invocationName = prefix + procedure.name.text;
+    if (procedure.isSetter) invocationName += '=';
+    Expression invocation = target.backendTarget.instantiateInvocation(
+        target.loader.coreTypes,
+        new ThisExpression(),
+        invocationName,
+        new Arguments.forwarded(procedure.function, library.library),
+        procedure.fileOffset,
+        /*isSuper=*/ false);
+    Expression result = new MethodInvocation(new ThisExpression(),
+        noSuchMethodName, new Arguments([invocation]), noSuchMethodInterface)
+      ..fileOffset = procedure.fileOffset;
+    if (procedure.function.returnType is! VoidType) {
+      result = new AsExpression(result, procedure.function.returnType)
+        ..isTypeError = true
+        ..isForDynamic = true
+        ..isForNonNullableByDefault = library.isNonNullableByDefault
+        ..fileOffset = procedure.fileOffset;
+    }
+    procedure.function.body = new ReturnStatement(result)
+      ..fileOffset = procedure.fileOffset;
+    procedure.function.body.parent = procedure.function;
+    procedure.function.asyncMarker = AsyncMarker.Sync;
+    procedure.function.dartAsyncMarker = AsyncMarker.Sync;
+
+    procedure.isAbstract = false;
+    procedure.isNoSuchMethodForwarder = true;
+    procedure.isMemberSignature = false;
+    procedure.isForwardingStub = false;
+    procedure.isForwardingSemiStub = false;
+    procedure.memberSignatureOrigin = null;
+    procedure.forwardingStubInterfaceTarget = null;
+    procedure.forwardingStubSuperTarget = null;
+  }
+
+  void _addRedirectingConstructor(ProcedureBuilder constructorBuilder,
       SourceLibraryBuilder library, Field referenceFrom) {
     // Add a new synthetic field to this class for representing factory
     // constructors. This is used to support resolving such constructors in
@@ -1006,7 +906,7 @@
                 // only legal to do to things in the kernel tree.
                 Field referenceFrom =
                     referencesFromIndexed?.lookupField("_redirecting#");
-                addRedirectingConstructor(declaration, library, referenceFrom);
+                _addRedirectingConstructor(declaration, library, referenceFrom);
               }
               if (targetBuilder is FunctionBuilder) {
                 List<DartType> typeArguments = declaration.typeArguments ??
@@ -1845,3 +1745,17 @@
     }
   }
 }
+
+/// Returns `true` if override problems should be overlooked.
+///
+/// This is needed for the current encoding of some JavaScript implementation
+/// classes that are not valid Dart. For instance `JSInt` in
+/// 'dart:_interceptors' that implements both `int` and `double`, and `JsArray`
+/// in `dart:js` that implement both `ListMixin` and `JsObject`.
+bool shouldOverrideProblemBeOverlooked(SourceClassBuilder classBuilder) {
+  String uri = '${classBuilder.library.importUri}';
+  return uri == 'dart:js' &&
+          classBuilder.fileUri.pathSegments.last == 'js.dart' ||
+      uri == 'dart:_interceptors' &&
+          classBuilder.fileUri.pathSegments.last == 'js_number.dart';
+}
diff --git a/pkg/front_end/test/spell_checking_list_code.txt b/pkg/front_end/test/spell_checking_list_code.txt
index 46bc5dd..66773d7 100644
--- a/pkg/front_end/test/spell_checking_list_code.txt
+++ b/pkg/front_end/test/spell_checking_list_code.txt
@@ -54,6 +54,7 @@
 artificial
 asgerf
 askesc
+aspect
 aspx
 assigning
 assigns
@@ -506,6 +507,7 @@
 ids
 iff
 il
+ill
 imitate
 immutability
 impl
@@ -828,6 +830,7 @@
 progresses
 proof
 prop
+propagated
 propose
 proposed
 proto
diff --git a/pkg/front_end/testcases/expression/set_literal.expression.yaml.expect b/pkg/front_end/testcases/expression/set_literal.expression.yaml.expect
index c2c42bc..d4d5c54 100644
--- a/pkg/front_end/testcases/expression/set_literal.expression.yaml.expect
+++ b/pkg/front_end/testcases/expression/set_literal.expression.yaml.expect
@@ -1,4 +1,7 @@
 Errors: {
 }
 method /* from org-dartlang-debug:synthetic_debug_expression */ debugExpr() → dynamic
-  return let final dart.core::Set<dart.core::String*>* #t1 = dart.collection::LinkedHashSet::•<dart.core::String*>() in let final dynamic #t2 = #t1.{dart.core::Set::add}("a") in #t1;
+  return block {
+    final dart.core::Set<dart.core::String*>* #t1 = dart.collection::LinkedHashSet::•<dart.core::String*>();
+    #t1.{dart.core::Set::add}("a");
+  } =>#t1;
diff --git a/pkg/front_end/testcases/extensions/ambiguous.dart.outline.expect b/pkg/front_end/testcases/extensions/ambiguous.dart.outline.expect
index 5ee4ba9..16c230a 100644
--- a/pkg/front_end/testcases/extensions/ambiguous.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/ambiguous.dart.outline.expect
@@ -5,16 +5,16 @@
 class C extends core::Object {
   synthetic constructor •() → self::C*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A on self::C* {
   method method = self::A|method;
diff --git a/pkg/front_end/testcases/extensions/ambiguous.dart.strong.expect b/pkg/front_end/testcases/extensions/ambiguous.dart.strong.expect
index a54a55b..399704a 100644
--- a/pkg/front_end/testcases/extensions/ambiguous.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/ambiguous.dart.strong.expect
@@ -153,16 +153,16 @@
   synthetic constructor •() → self::C*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A on self::C* {
   method method = self::A|method;
diff --git a/pkg/front_end/testcases/extensions/ambiguous.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/ambiguous.dart.strong.transformed.expect
index a54a55b..399704a 100644
--- a/pkg/front_end/testcases/extensions/ambiguous.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/ambiguous.dart.strong.transformed.expect
@@ -153,16 +153,16 @@
   synthetic constructor •() → self::C*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A on self::C* {
   method method = self::A|method;
diff --git a/pkg/front_end/testcases/extensions/annotations.dart.outline.expect b/pkg/front_end/testcases/extensions/annotations.dart.outline.expect
index ff75d1b..2fe5083 100644
--- a/pkg/front_end/testcases/extensions/annotations.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/annotations.dart.outline.expect
@@ -11,16 +11,16 @@
   @core::pragma::_("dart2js:noInline")
   static method staticMethod() → dynamic
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method extensionInstanceMethod = self::Extension|extensionInstanceMethod;
diff --git a/pkg/front_end/testcases/extensions/annotations.dart.strong.expect b/pkg/front_end/testcases/extensions/annotations.dart.strong.expect
index 44c7c8a..8eb9132 100644
--- a/pkg/front_end/testcases/extensions/annotations.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/annotations.dart.strong.expect
@@ -10,16 +10,16 @@
   method instanceMethod() → dynamic {}
   @#C3
   static method staticMethod() → dynamic {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method extensionInstanceMethod = self::Extension|extensionInstanceMethod;
diff --git a/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect
index 44c7c8a..8eb9132 100644
--- a/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect
@@ -10,16 +10,16 @@
   method instanceMethod() → dynamic {}
   @#C3
   static method staticMethod() → dynamic {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method extensionInstanceMethod = self::Extension|extensionInstanceMethod;
diff --git a/pkg/front_end/testcases/extensions/call_methods.dart.outline.expect b/pkg/front_end/testcases/extensions/call_methods.dart.outline.expect
index f5610f5..c4b3280 100644
--- a/pkg/front_end/testcases/extensions/call_methods.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/call_methods.dart.outline.expect
@@ -7,32 +7,32 @@
     ;
   get call() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends core::Object {
   synthetic constructor •() → self::B*
     ;
   get call() → () →* core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on core::int* {
   get call = self::_extension#0|get#call;
diff --git a/pkg/front_end/testcases/extensions/call_methods.dart.strong.expect b/pkg/front_end/testcases/extensions/call_methods.dart.strong.expect
index 6ad9135..387c002 100644
--- a/pkg/front_end/testcases/extensions/call_methods.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/call_methods.dart.strong.expect
@@ -101,16 +101,16 @@
     ;
   get call() → core::String*
     return "My name is A";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends core::Object {
   synthetic constructor •() → self::B*
@@ -118,16 +118,16 @@
     ;
   get call() → () →* core::String*
     return () → core::String* => "My name is B";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on core::int* {
   get call = self::_extension#0|get#call;
diff --git a/pkg/front_end/testcases/extensions/check_bounds.dart.outline.expect b/pkg/front_end/testcases/extensions/check_bounds.dart.outline.expect
index 1a72e8b..abf68cd 100644
--- a/pkg/front_end/testcases/extensions/check_bounds.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/check_bounds.dart.outline.expect
@@ -6,16 +6,16 @@
 class A extends core::Object {
   synthetic constructor •() → self::A*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -24,16 +24,16 @@
 class Class<T extends self::A* = self::A*> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends self::B* = self::B*> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/check_bounds.dart.strong.expect b/pkg/front_end/testcases/extensions/check_bounds.dart.strong.expect
index 1d88a8a..f8cf127 100644
--- a/pkg/front_end/testcases/extensions/check_bounds.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/check_bounds.dart.strong.expect
@@ -811,16 +811,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -831,16 +831,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends self::B* = self::B*> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/check_bounds.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/check_bounds.dart.strong.transformed.expect
index 1d88a8a..f8cf127 100644
--- a/pkg/front_end/testcases/extensions/check_bounds.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/check_bounds.dart.strong.transformed.expect
@@ -811,16 +811,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -831,16 +831,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends self::B* = self::B*> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/compounds.dart.outline.expect b/pkg/front_end/testcases/extensions/compounds.dart.outline.expect
index a4408ae..4a17e87 100644
--- a/pkg/front_end/testcases/extensions/compounds.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/compounds.dart.outline.expect
@@ -12,43 +12,43 @@
     ;
   method toString() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class extends core::Object {
   field self::Number* field;
   constructor •(self::Number* field) → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class IntClass extends core::Object {
   field core::int* field;
   constructor •(core::int* field) → self::IntClass*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension NumberExtension on self::Number* {
   operator + = self::NumberExtension|+;
diff --git a/pkg/front_end/testcases/extensions/compounds.dart.strong.expect b/pkg/front_end/testcases/extensions/compounds.dart.strong.expect
index b69e531..b8c8a05 100644
--- a/pkg/front_end/testcases/extensions/compounds.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/compounds.dart.strong.expect
@@ -13,45 +13,45 @@
     return other is self::Number* && this.{self::Number::value}.{core::num::==}(other{self::Number*}.{self::Number::value});
   method toString() → core::String*
     return "Number(${this.{self::Number::value}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class extends core::Object {
   field self::Number* field;
   constructor •(self::Number* field) → self::Class*
     : self::Class::field = field, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class IntClass extends core::Object {
   field core::int* field;
   constructor •(core::int* field) → self::IntClass*
     : self::IntClass::field = field, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension NumberExtension on self::Number* {
   operator + = self::NumberExtension|+;
diff --git a/pkg/front_end/testcases/extensions/compounds.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/compounds.dart.strong.transformed.expect
index b69e531..b8c8a05 100644
--- a/pkg/front_end/testcases/extensions/compounds.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/compounds.dart.strong.transformed.expect
@@ -13,45 +13,45 @@
     return other is self::Number* && this.{self::Number::value}.{core::num::==}(other{self::Number*}.{self::Number::value});
   method toString() → core::String*
     return "Number(${this.{self::Number::value}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class extends core::Object {
   field self::Number* field;
   constructor •(self::Number* field) → self::Class*
     : self::Class::field = field, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class IntClass extends core::Object {
   field core::int* field;
   constructor •(core::int* field) → self::IntClass*
     : self::IntClass::field = field, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension NumberExtension on self::Number* {
   operator + = self::NumberExtension|+;
diff --git a/pkg/front_end/testcases/extensions/conflicts.dart.outline.expect b/pkg/front_end/testcases/extensions/conflicts.dart.outline.expect
index 6fb3b5f..b200d91 100644
--- a/pkg/front_end/testcases/extensions/conflicts.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/conflicts.dart.outline.expect
@@ -22,30 +22,30 @@
 class Class1 extends core::Object {
   synthetic constructor •() → self::Class1*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   synthetic constructor •() → self::Class2*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension DuplicateExtensionName on self::Class1* {
   method uniqueMethod1 = self::DuplicateExtensionName|uniqueMethod1;
diff --git a/pkg/front_end/testcases/extensions/conflicts.dart.strong.expect b/pkg/front_end/testcases/extensions/conflicts.dart.strong.expect
index 9764dae..e7354bb 100644
--- a/pkg/front_end/testcases/extensions/conflicts.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/conflicts.dart.strong.expect
@@ -29,31 +29,31 @@
   synthetic constructor •() → self::Class1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   synthetic constructor •() → self::Class2*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension DuplicateExtensionName on self::Class1* {
   method uniqueMethod1 = self::DuplicateExtensionName|uniqueMethod1;
diff --git a/pkg/front_end/testcases/extensions/conflicts.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/conflicts.dart.strong.transformed.expect
index 9764dae..e7354bb 100644
--- a/pkg/front_end/testcases/extensions/conflicts.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/conflicts.dart.strong.transformed.expect
@@ -29,31 +29,31 @@
   synthetic constructor •() → self::Class1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   synthetic constructor •() → self::Class2*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension DuplicateExtensionName on self::Class1* {
   method uniqueMethod1 = self::DuplicateExtensionName|uniqueMethod1;
diff --git a/pkg/front_end/testcases/extensions/default_values.dart.outline.expect b/pkg/front_end/testcases/extensions/default_values.dart.outline.expect
index 04ed817..ee79db6 100644
--- a/pkg/front_end/testcases/extensions/default_values.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/default_values.dart.outline.expect
@@ -5,16 +5,16 @@
 class Class extends core::Object {
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method0 = self::Extension|method0;
diff --git a/pkg/front_end/testcases/extensions/default_values.dart.strong.expect b/pkg/front_end/testcases/extensions/default_values.dart.strong.expect
index c31a720..77d66dc 100644
--- a/pkg/front_end/testcases/extensions/default_values.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/default_values.dart.strong.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method0 = self::Extension|method0;
diff --git a/pkg/front_end/testcases/extensions/default_values.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/default_values.dart.strong.transformed.expect
index c31a720..77d66dc 100644
--- a/pkg/front_end/testcases/extensions/default_values.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/default_values.dart.strong.transformed.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method0 = self::Extension|method0;
diff --git a/pkg/front_end/testcases/extensions/direct_instance_access.dart.outline.expect b/pkg/front_end/testcases/extensions/direct_instance_access.dart.outline.expect
index 2d17121..92cc66a 100644
--- a/pkg/front_end/testcases/extensions/direct_instance_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/direct_instance_access.dart.outline.expect
@@ -6,31 +6,31 @@
   field dynamic field;
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   generic-covariant-impl field self::GenericClass::T* field;
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method readGetter = self::Extension|readGetter;
diff --git a/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.expect b/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.expect
index 17dadac..e2d649a 100644
--- a/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.expect
@@ -7,32 +7,32 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   generic-covariant-impl field self::GenericClass::T* field = null;
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method readGetter = self::Extension|readGetter;
diff --git a/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.transformed.expect
index 17dadac..e2d649a 100644
--- a/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.transformed.expect
@@ -7,32 +7,32 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   generic-covariant-impl field self::GenericClass::T* field = null;
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method readGetter = self::Extension|readGetter;
diff --git a/pkg/front_end/testcases/extensions/direct_static_access.dart.outline.expect b/pkg/front_end/testcases/extensions/direct_static_access.dart.outline.expect
index 7dd4ee1..bf7e89f 100644
--- a/pkg/front_end/testcases/extensions/direct_static_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/direct_static_access.dart.outline.expect
@@ -6,16 +6,16 @@
   static field dynamic field;
   synthetic constructor •() → self::Class<self::Class::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   static get property = get self::Extension|property;
diff --git a/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.expect b/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.expect
index 1a55006..c08eaf19 100644
--- a/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   static get property = get self::Extension|property;
diff --git a/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.transformed.expect
index 1a55006..c08eaf19 100644
--- a/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.transformed.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   static get property = get self::Extension|property;
diff --git a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.outline.expect b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.outline.expect
index a2ea0ee..166c1f6 100644
--- a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.outline.expect
@@ -7,15 +7,15 @@
     ;
   method noSuchMethod(core::Invocation* i) → dynamic
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ClassExtension on self::Class* {
   method method = self::ClassExtension|method;
diff --git a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.expect b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.expect
index 627b139..964fb26 100644
--- a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.expect
@@ -8,15 +8,15 @@
     ;
   method noSuchMethod(core::Invocation* i) → dynamic
     return 123;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ClassExtension on self::Class* {
   method method = self::ClassExtension|method;
diff --git a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.transformed.expect
index 627b139..964fb26 100644
--- a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.transformed.expect
@@ -8,15 +8,15 @@
     ;
   method noSuchMethod(core::Invocation* i) → dynamic
     return 123;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ClassExtension on self::Class* {
   method method = self::ClassExtension|method;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.outline.expect b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.outline.expect
index 293f3df..60d7163 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.outline.expect
@@ -7,16 +7,16 @@
   field core::int* field2;
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class* {
   get field = self::Extension1|get#field;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.expect b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.expect
index 1de117d..b18b268 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.expect
@@ -8,16 +8,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class* {
   get field = self::Extension1|get#field;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.transformed.expect
index 47097a2..465effe 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.transformed.expect
@@ -8,16 +8,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class* {
   get field = self::Extension1|get#field;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.outline.expect b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.outline.expect
index 21fc22e..5b69371 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.outline.expect
@@ -5,16 +5,16 @@
 class A extends core::Object {
   synthetic constructor •() → self::A*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -27,16 +27,16 @@
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.expect b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.expect
index 3d6532f..d15b0fc 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -31,16 +31,16 @@
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.transformed.expect
index 3d6532f..d15b0fc 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.transformed.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -31,16 +31,16 @@
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.outline.expect b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.outline.expect
index c63ea7d..fd4705e 100644
--- a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.outline.expect
@@ -7,16 +7,16 @@
   generic-covariant-impl field self::Class::T* field2;
   constructor •(self::Class::T* field1, self::Class::T* field2) → self::Class<self::Class::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1<T extends core::num* = core::num*> on self::Class<T*>* {
   static field latestType = self::Extension1|latestType;
diff --git a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.expect b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.expect
index adc49e4..e7c4a0c 100644
--- a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.expect
@@ -8,16 +8,16 @@
   constructor •(self::Class::T* field1, self::Class::T* field2) → self::Class<self::Class::T*>*
     : self::Class::field1 = field1, self::Class::field2 = field2, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1<T extends core::num* = core::num*> on self::Class<T*>* {
   static field latestType = self::Extension1|latestType;
diff --git a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.transformed.expect
index 7239cba..2782699 100644
--- a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.transformed.expect
@@ -8,16 +8,16 @@
   constructor •(self::Class::T* field1, self::Class::T* field2) → self::Class<self::Class::T*>*
     : self::Class::field1 = field1, self::Class::field2 = field2, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1<T extends core::num* = core::num*> on self::Class<T*>* {
   static field latestType = self::Extension1|latestType;
diff --git a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.outline.expect b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.outline.expect
index f5961c4..3d7ea6e 100644
--- a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.outline.expect
@@ -5,16 +5,16 @@
 class Class extends core::Object {
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
 }
diff --git a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.expect b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.expect
index f0bae7e..5c22ecf 100644
--- a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.expect
@@ -29,16 +29,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
 }
diff --git a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.transformed.expect
index f0bae7e..5c22ecf 100644
--- a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.transformed.expect
@@ -29,16 +29,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
 }
diff --git a/pkg/front_end/testcases/extensions/explicit_this.dart.outline.expect b/pkg/front_end/testcases/extensions/explicit_this.dart.outline.expect
index fee8d56..42f3e5d 100644
--- a/pkg/front_end/testcases/extensions/explicit_this.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/explicit_this.dart.outline.expect
@@ -8,16 +8,16 @@
     ;
   method method1() → void
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/explicit_this.dart.strong.expect b/pkg/front_end/testcases/extensions/explicit_this.dart.strong.expect
index ef5a89a..08b2bca 100644
--- a/pkg/front_end/testcases/extensions/explicit_this.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/explicit_this.dart.strong.expect
@@ -8,16 +8,16 @@
     : super core::Object::•()
     ;
   method method1() → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/explicit_this.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/explicit_this.dart.strong.transformed.expect
index ef5a89a..08b2bca 100644
--- a/pkg/front_end/testcases/extensions/explicit_this.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/explicit_this.dart.strong.transformed.expect
@@ -8,16 +8,16 @@
     : super core::Object::•()
     ;
   method method1() → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/export_twice.dart.outline.expect b/pkg/front_end/testcases/extensions/export_twice.dart.outline.expect
index 1ee21db..ef8bae9 100644
--- a/pkg/front_end/testcases/extensions/export_twice.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/export_twice.dart.outline.expect
@@ -14,16 +14,16 @@
 class Class extends core::Object {
   synthetic constructor •() → self2::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self2::Class* {
   method method = self2::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/export_twice.dart.strong.expect b/pkg/front_end/testcases/extensions/export_twice.dart.strong.expect
index bc0e513..cbd92ef 100644
--- a/pkg/front_end/testcases/extensions/export_twice.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/export_twice.dart.strong.expect
@@ -17,16 +17,16 @@
   synthetic constructor •() → exp::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on exp::Class* {
   method method = exp::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/export_twice.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/export_twice.dart.strong.transformed.expect
index bc0e513..cbd92ef 100644
--- a/pkg/front_end/testcases/extensions/export_twice.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/export_twice.dart.strong.transformed.expect
@@ -17,16 +17,16 @@
   synthetic constructor •() → exp::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on exp::Class* {
   method method = exp::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/extension_call.dart.outline.expect b/pkg/front_end/testcases/extensions/extension_call.dart.outline.expect
index b95b9c6..aebf9c6 100644
--- a/pkg/front_end/testcases/extensions/extension_call.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/extension_call.dart.outline.expect
@@ -7,16 +7,16 @@
     ;
   method method(generic-covariant-impl self::Class::T* a) → self::Class::T*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method call = self::Extension|call;
diff --git a/pkg/front_end/testcases/extensions/extension_call.dart.strong.expect b/pkg/front_end/testcases/extensions/extension_call.dart.strong.expect
index 946cf57..46c2f58 100644
--- a/pkg/front_end/testcases/extensions/extension_call.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/extension_call.dart.strong.expect
@@ -8,16 +8,16 @@
     ;
   method method(generic-covariant-impl self::Class::T* a) → self::Class::T*
     return a;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method call = self::Extension|call;
diff --git a/pkg/front_end/testcases/extensions/extension_call.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/extension_call.dart.strong.transformed.expect
index 946cf57..46c2f58 100644
--- a/pkg/front_end/testcases/extensions/extension_call.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/extension_call.dart.strong.transformed.expect
@@ -8,16 +8,16 @@
     ;
   method method(generic-covariant-impl self::Class::T* a) → self::Class::T*
     return a;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method call = self::Extension|call;
diff --git a/pkg/front_end/testcases/extensions/extension_constructor.dart.outline.expect b/pkg/front_end/testcases/extensions/extension_constructor.dart.outline.expect
index 85085ee..dbb4f7d 100644
--- a/pkg/front_end/testcases/extensions/extension_constructor.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/extension_constructor.dart.outline.expect
@@ -42,16 +42,16 @@
 class Class extends core::Object {
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.expect b/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.expect
index d5d8cb2..c1a2daf 100644
--- a/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.expect
@@ -43,16 +43,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.transformed.expect
index d5d8cb2..c1a2daf 100644
--- a/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.transformed.expect
@@ -43,16 +43,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/extension_methods.dart.outline.expect b/pkg/front_end/testcases/extensions/extension_methods.dart.outline.expect
index f327887..fe9807d 100644
--- a/pkg/front_end/testcases/extensions/extension_methods.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/extension_methods.dart.outline.expect
@@ -9,16 +9,16 @@
     ;
   get one() → core::int*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension E on self::C* {
   get two = self::E|get#two;
diff --git a/pkg/front_end/testcases/extensions/extension_methods.dart.strong.expect b/pkg/front_end/testcases/extensions/extension_methods.dart.strong.expect
index b6a1193..17c4511 100644
--- a/pkg/front_end/testcases/extensions/extension_methods.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/extension_methods.dart.strong.expect
@@ -11,16 +11,16 @@
     ;
   get one() → core::int*
     return 1;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension E on self::C* {
   get two = self::E|get#two;
diff --git a/pkg/front_end/testcases/extensions/extension_methods.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/extension_methods.dart.strong.transformed.expect
index b6a1193..17c4511 100644
--- a/pkg/front_end/testcases/extensions/extension_methods.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/extension_methods.dart.strong.transformed.expect
@@ -11,16 +11,16 @@
     ;
   get one() → core::int*
     return 1;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension E on self::C* {
   get two = self::E|get#two;
diff --git a/pkg/front_end/testcases/extensions/extension_setter.dart.outline.expect b/pkg/front_end/testcases/extensions/extension_setter.dart.outline.expect
index a46d986..aae8168 100644
--- a/pkg/front_end/testcases/extensions/extension_setter.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/extension_setter.dart.outline.expect
@@ -6,30 +6,30 @@
   field core::int* field;
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get simpleSetter = self::Extension|get#simpleSetter;
diff --git a/pkg/front_end/testcases/extensions/extension_setter.dart.strong.expect b/pkg/front_end/testcases/extensions/extension_setter.dart.strong.expect
index 98f08d2..a4bb6ed 100644
--- a/pkg/front_end/testcases/extensions/extension_setter.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/extension_setter.dart.strong.expect
@@ -7,31 +7,31 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get simpleSetter = self::Extension|get#simpleSetter;
diff --git a/pkg/front_end/testcases/extensions/extension_setter.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/extension_setter.dart.strong.transformed.expect
index 245ead1..b951605 100644
--- a/pkg/front_end/testcases/extensions/extension_setter.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/extension_setter.dart.strong.transformed.expect
@@ -7,31 +7,31 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get simpleSetter = self::Extension|get#simpleSetter;
diff --git a/pkg/front_end/testcases/extensions/extension_setter_error.dart.outline.expect b/pkg/front_end/testcases/extensions/extension_setter_error.dart.outline.expect
index 4044e84..1423f19 100644
--- a/pkg/front_end/testcases/extensions/extension_setter_error.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/extension_setter_error.dart.outline.expect
@@ -5,16 +5,16 @@
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   set setter = self::GenericExtension|set#setter;
diff --git a/pkg/front_end/testcases/extensions/extension_setter_error.dart.strong.expect b/pkg/front_end/testcases/extensions/extension_setter_error.dart.strong.expect
index 917ce53..9e347d5 100644
--- a/pkg/front_end/testcases/extensions/extension_setter_error.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/extension_setter_error.dart.strong.expect
@@ -14,16 +14,16 @@
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   set setter = self::GenericExtension|set#setter;
diff --git a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.outline.expect b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.outline.expect
index 6155609..54fb6a7d 100644
--- a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.outline.expect
@@ -5,16 +5,16 @@
 class Class<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.expect b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.expect
index f7c38aa..2f09d15 100644
--- a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.transformed.expect
index f7c38aa..2f09d15 100644
--- a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.transformed.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.outline.expect b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.outline.expect
index 9d49790..3b49162 100644
--- a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.outline.expect
@@ -9,16 +9,16 @@
     ;
   set m2(core::int* x) → void
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension0 on self::Class* {
   get m2 = self::Extension0|get#m2;
diff --git a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.expect b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.expect
index 966e6eb..01b0f59 100644
--- a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.expect
@@ -72,16 +72,16 @@
   get m1() → core::int*
     return 0;
   set m2(core::int* x) → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension0 on self::Class* {
   get m2 = self::Extension0|get#m2;
diff --git a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.transformed.expect
index 966e6eb..01b0f59 100644
--- a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.transformed.expect
@@ -72,16 +72,16 @@
   get m1() → core::int*
     return 0;
   set m2(core::int* x) → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension0 on self::Class* {
   get m2 = self::Extension0|get#m2;
diff --git a/pkg/front_end/testcases/extensions/if_null.dart.outline.expect b/pkg/front_end/testcases/extensions/if_null.dart.outline.expect
index 3d3aea8..793e929 100644
--- a/pkg/front_end/testcases/extensions/if_null.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/if_null.dart.outline.expect
@@ -6,16 +6,16 @@
   field core::int* field;
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get property = self::Extension|get#property;
diff --git a/pkg/front_end/testcases/extensions/if_null.dart.strong.expect b/pkg/front_end/testcases/extensions/if_null.dart.strong.expect
index 4a04ad0..3b988f9 100644
--- a/pkg/front_end/testcases/extensions/if_null.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/if_null.dart.strong.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get property = self::Extension|get#property;
diff --git a/pkg/front_end/testcases/extensions/if_null.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/if_null.dart.strong.transformed.expect
index cd0b1b3..611d1c8 100644
--- a/pkg/front_end/testcases/extensions/if_null.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/if_null.dart.strong.transformed.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get property = self::Extension|get#property;
diff --git a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.outline.expect b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.outline.expect
index 21fc22e..5b69371 100644
--- a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.outline.expect
@@ -5,16 +5,16 @@
 class A extends core::Object {
   synthetic constructor •() → self::A*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -27,16 +27,16 @@
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.expect b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.expect
index e9f7f82..6d27bcd 100644
--- a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -31,16 +31,16 @@
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.transformed.expect
index e9f7f82..6d27bcd 100644
--- a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.transformed.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -31,16 +31,16 @@
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/implicit_this.dart.outline.expect b/pkg/front_end/testcases/extensions/implicit_this.dart.outline.expect
index fee8d56..42f3e5d 100644
--- a/pkg/front_end/testcases/extensions/implicit_this.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/implicit_this.dart.outline.expect
@@ -8,16 +8,16 @@
     ;
   method method1() → void
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/implicit_this.dart.strong.expect b/pkg/front_end/testcases/extensions/implicit_this.dart.strong.expect
index ef5a89a..08b2bca 100644
--- a/pkg/front_end/testcases/extensions/implicit_this.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/implicit_this.dart.strong.expect
@@ -8,16 +8,16 @@
     : super core::Object::•()
     ;
   method method1() → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/implicit_this.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/implicit_this.dart.strong.transformed.expect
index ef5a89a..08b2bca 100644
--- a/pkg/front_end/testcases/extensions/implicit_this.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/implicit_this.dart.strong.transformed.expect
@@ -8,16 +8,16 @@
     : super core::Object::•()
     ;
   method method1() → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/index.dart.outline.expect b/pkg/front_end/testcases/extensions/index.dart.outline.expect
index da0ddd9..6e37096 100644
--- a/pkg/front_end/testcases/extensions/index.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/index.dart.outline.expect
@@ -10,16 +10,16 @@
     ;
   method put(generic-covariant-impl self::MapLike::K* key, generic-covariant-impl self::MapLike::V* value) → self::MapLike::V*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<K extends core::Object* = dynamic, V extends core::Object* = dynamic> on self::MapLike<K*, V*>* {
   operator [] = self::Extension|[];
diff --git a/pkg/front_end/testcases/extensions/index.dart.strong.expect b/pkg/front_end/testcases/extensions/index.dart.strong.expect
index 67d8909..27bbfae 100644
--- a/pkg/front_end/testcases/extensions/index.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/index.dart.strong.expect
@@ -11,16 +11,16 @@
     return this.{self::MapLike::_map}.{core::Map::[]}(key);
   method put(generic-covariant-impl self::MapLike::K* key, generic-covariant-impl self::MapLike::V* value) → self::MapLike::V*
     return let final core::Map<self::MapLike::K*, self::MapLike::V*>* #t1 = this.{self::MapLike::_map} in let final self::MapLike::K* #t2 = key in let final self::MapLike::V* #t3 = value in let final void #t4 = #t1.{core::Map::[]=}(#t2, #t3) in #t3;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<K extends core::Object* = dynamic, V extends core::Object* = dynamic> on self::MapLike<K*, V*>* {
   operator [] = self::Extension|[];
diff --git a/pkg/front_end/testcases/extensions/index.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/index.dart.strong.transformed.expect
index f406204..dadf664 100644
--- a/pkg/front_end/testcases/extensions/index.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/index.dart.strong.transformed.expect
@@ -11,16 +11,16 @@
     return this.{self::MapLike::_map}.{core::Map::[]}(key);
   method put(generic-covariant-impl self::MapLike::K* key, generic-covariant-impl self::MapLike::V* value) → self::MapLike::V*
     return let final core::Map<self::MapLike::K*, self::MapLike::V*>* #t1 = this.{self::MapLike::_map} in let final self::MapLike::K* #t2 = key in let final self::MapLike::V* #t3 = value in let final void #t4 = #t1.{core::Map::[]=}(#t2, #t3) in #t3;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<K extends core::Object* = dynamic, V extends core::Object* = dynamic> on self::MapLike<K*, V*>* {
   operator [] = self::Extension|[];
diff --git a/pkg/front_end/testcases/extensions/instance_access.dart.outline.expect b/pkg/front_end/testcases/extensions/instance_access.dart.outline.expect
index 7bdfef2..4c95115 100644
--- a/pkg/front_end/testcases/extensions/instance_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/instance_access.dart.outline.expect
@@ -8,15 +8,15 @@
     ;
   method toString() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -24,15 +24,15 @@
     ;
   method toString() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/instance_access.dart.strong.expect b/pkg/front_end/testcases/extensions/instance_access.dart.strong.expect
index ca462d0..d04e6106 100644
--- a/pkg/front_end/testcases/extensions/instance_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/instance_access.dart.strong.expect
@@ -9,15 +9,15 @@
     ;
   method toString() → core::String*
     return "Class1(${this.{self::Class1::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -26,15 +26,15 @@
     ;
   method toString() → core::String*
     return "Class2(${this.{self::Class2::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/instance_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/instance_access.dart.strong.transformed.expect
index b117363..0a149ba 100644
--- a/pkg/front_end/testcases/extensions/instance_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/instance_access.dart.strong.transformed.expect
@@ -9,15 +9,15 @@
     ;
   method toString() → core::String*
     return "Class1(${this.{self::Class1::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -26,15 +26,15 @@
     ;
   method toString() → core::String*
     return "Class2(${this.{self::Class2::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.outline.expect b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.outline.expect
index e33cdbd..010dee1 100644
--- a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.outline.expect
@@ -5,16 +5,16 @@
 class Class1 extends core::Object {
   synthetic constructor •() → self::Class1*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   static method staticMethod = self::Extension1|staticMethod;
diff --git a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.expect b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.expect
index 948d21b..edeff7b 100644
--- a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.expect
@@ -45,16 +45,16 @@
   synthetic constructor •() → self::Class1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   static method staticMethod = self::Extension1|staticMethod;
diff --git a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.transformed.expect
index 948d21b..edeff7b 100644
--- a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.transformed.expect
@@ -45,16 +45,16 @@
   synthetic constructor •() → self::Class1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   static method staticMethod = self::Extension1|staticMethod;
diff --git a/pkg/front_end/testcases/extensions/instance_members.dart.outline.expect b/pkg/front_end/testcases/extensions/instance_members.dart.outline.expect
index 04be94e..78fd7df 100644
--- a/pkg/front_end/testcases/extensions/instance_members.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/instance_members.dart.outline.expect
@@ -5,30 +5,30 @@
 class A1 extends core::Object {
   synthetic constructor •() → self::A1*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B1<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::B1<self::B1::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method1 = self::A2|method1;
diff --git a/pkg/front_end/testcases/extensions/instance_members.dart.strong.expect b/pkg/front_end/testcases/extensions/instance_members.dart.strong.expect
index 72cb315d..df3a40c 100644
--- a/pkg/front_end/testcases/extensions/instance_members.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/instance_members.dart.strong.expect
@@ -6,31 +6,31 @@
   synthetic constructor •() → self::A1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B1<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::B1<self::B1::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method1 = self::A2|method1;
diff --git a/pkg/front_end/testcases/extensions/instance_members.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/instance_members.dart.strong.transformed.expect
index 72cb315d..df3a40c 100644
--- a/pkg/front_end/testcases/extensions/instance_members.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/instance_members.dart.strong.transformed.expect
@@ -6,31 +6,31 @@
   synthetic constructor •() → self::A1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B1<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::B1<self::B1::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method1 = self::A2|method1;
diff --git a/pkg/front_end/testcases/extensions/instance_tearoff.dart.outline.expect b/pkg/front_end/testcases/extensions/instance_tearoff.dart.outline.expect
index 08380b2..4486c85 100644
--- a/pkg/front_end/testcases/extensions/instance_tearoff.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/instance_tearoff.dart.outline.expect
@@ -8,15 +8,15 @@
     ;
   method toString() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -24,15 +24,15 @@
     ;
   method toString() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.expect b/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.expect
index 9508bad..8bc8b21 100644
--- a/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.expect
@@ -9,15 +9,15 @@
     ;
   method toString() → core::String*
     return "Class1(${this.{self::Class1::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -26,15 +26,15 @@
     ;
   method toString() → core::String*
     return "Class2(${this.{self::Class2::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.transformed.expect
index aabacb2..1083c18 100644
--- a/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.transformed.expect
@@ -9,15 +9,15 @@
     ;
   method toString() → core::String*
     return "Class1(${this.{self::Class1::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -26,15 +26,15 @@
     ;
   method toString() → core::String*
     return "Class2(${this.{self::Class2::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/internal_resolution.dart.outline.expect b/pkg/front_end/testcases/extensions/internal_resolution.dart.outline.expect
index 1c64152..4ea05c6 100644
--- a/pkg/front_end/testcases/extensions/internal_resolution.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/internal_resolution.dart.outline.expect
@@ -6,16 +6,16 @@
   field core::int* field;
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on self::Class* {
   get property1 = self::_extension#0|get#property1;
diff --git a/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.expect b/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.expect
index dadb2db..36d8d33 100644
--- a/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on self::Class* {
   get property1 = self::_extension#0|get#property1;
diff --git a/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.transformed.expect
index d9024f1..311c941 100644
--- a/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.transformed.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on self::Class* {
   get property1 = self::_extension#0|get#property1;
diff --git a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.outline.expect b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.outline.expect
index 0b7201a..bbcd313 100644
--- a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.outline.expect
@@ -5,30 +5,30 @@
 class Class extends core::Object {
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.expect b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.expect
index 431609f..4aa3725 100644
--- a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.expect
@@ -128,31 +128,31 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.transformed.expect
index 431609f..4aa3725 100644
--- a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.transformed.expect
@@ -128,31 +128,31 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/issue38600.dart.outline.expect b/pkg/front_end/testcases/extensions/issue38600.dart.outline.expect
index ed495ec..fbece28 100644
--- a/pkg/front_end/testcases/extensions/issue38600.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/issue38600.dart.outline.expect
@@ -51,16 +51,16 @@
 class Class<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on invalid-type {
 }
diff --git a/pkg/front_end/testcases/extensions/issue38600.dart.strong.expect b/pkg/front_end/testcases/extensions/issue38600.dart.strong.expect
index 373bda2..af7f9d0 100644
--- a/pkg/front_end/testcases/extensions/issue38600.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/issue38600.dart.strong.expect
@@ -52,16 +52,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on invalid-type {
 }
diff --git a/pkg/front_end/testcases/extensions/issue38600.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/issue38600.dart.strong.transformed.expect
index 373bda2..af7f9d0 100644
--- a/pkg/front_end/testcases/extensions/issue38600.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/issue38600.dart.strong.transformed.expect
@@ -52,16 +52,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on invalid-type {
 }
diff --git a/pkg/front_end/testcases/extensions/issue38745.dart.outline.expect b/pkg/front_end/testcases/extensions/issue38745.dart.outline.expect
index 166ad22..83e0f7d 100644
--- a/pkg/front_end/testcases/extensions/issue38745.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/issue38745.dart.outline.expect
@@ -31,16 +31,16 @@
 class C<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::C<self::C::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
<