diff --git a/pkg/_js_interop_checks/lib/src/transformations/js_util_optimizer.dart b/pkg/_js_interop_checks/lib/src/transformations/js_util_optimizer.dart
index d1d72dc..bd38471 100644
--- a/pkg/_js_interop_checks/lib/src/transformations/js_util_optimizer.dart
+++ b/pkg/_js_interop_checks/lib/src/transformations/js_util_optimizer.dart
@@ -35,20 +35,21 @@
   /// for any argument type. Lowers `getProperty(o, name)` to
   /// `JS('Object|Null', '#.#', o, name)`.
   StaticInvocation _lowerGetProperty(StaticInvocation node) {
-    Arguments args = node.arguments;
-    assert(args.positional.length == 2);
+    Arguments arguments = node.arguments;
+    assert(arguments.types.isEmpty);
+    assert(arguments.positional.length == 2);
+    assert(arguments.named.isEmpty);
     return StaticInvocation(
         _jsTarget,
         Arguments(
           [
             StringLiteral("Object|Null"),
             StringLiteral("#.#"),
-            args.positional.first,
-            args.positional.last
+            ...arguments.positional
           ],
           // TODO(rileyporter): Copy type from getProperty when it's generic.
           types: [DynamicType()],
-        ))
+        )..fileOffset = node.arguments.fileOffset)
       ..fileOffset = node.fileOffset;
   }
 }
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/sort_child_property_last.dart b/pkg/analysis_server/lib/src/services/correction/dart/sort_child_property_last.dart
index 4475559..d478b33 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/sort_child_property_last.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/sort_child_property_last.dart
@@ -6,6 +6,7 @@
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
@@ -45,15 +46,38 @@
     }
 
     await builder.addDartFileEdit(file, (fileEditBuilder) {
-      var start = childProp.beginToken.previous.end;
-      var end = childProp.endToken.next.end;
-      var childRange = range.startOffsetEndOffset(start, end);
+      var hasTrailingComma = last.endToken.next.type == TokenType.COMMA;
 
+      var childStart = childProp.beginToken.previous.end;
+      var childEnd = childProp.endToken.next.end;
+      var childRange = range.startOffsetEndOffset(childStart, childEnd);
+
+      var deletionRange = childRange;
+      if (childProp == args.arguments.first) {
+        var deletionStart = childProp.offset;
+        var deletionEnd = args.arguments[1].offset;
+        deletionRange = range.startOffsetEndOffset(deletionStart, deletionEnd);
+      }
+
+      if (!hasTrailingComma) {
+        childEnd = childProp.end;
+        childRange = range.startOffsetEndOffset(childStart, childEnd);
+      }
       var childText = utils.getRangeText(childRange);
-      fileEditBuilder.addSimpleReplacement(childRange, '');
-      fileEditBuilder.addSimpleInsertion(last.end + 1, childText);
 
-      builder.setSelection(Position(file, last.end + 1));
+      var insertionPoint = last.end;
+      if (hasTrailingComma) {
+        insertionPoint = last.endToken.next.end;
+      } else if (childStart == childProp.offset) {
+        childText = ', $childText';
+      } else {
+        childText = ',$childText';
+      }
+
+      fileEditBuilder.addDeletion(deletionRange);
+      fileEditBuilder.addSimpleInsertion(insertionPoint, childText);
+
+      builder.setSelection(Position(file, insertionPoint));
     });
   }
 
diff --git a/pkg/analysis_server/test/src/services/correction/assist/sort_child_property_last_test.dart b/pkg/analysis_server/test/src/services/correction/assist/sort_child_property_last_test.dart
index 2aea7cc..b407482 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/sort_child_property_last_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/sort_child_property_last_test.dart
@@ -73,11 +73,12 @@
     await assertNoAssist();
   }
 
-  Future<void> test_sort() async {
+  Future<void> test_sort_middleArgument() async {
     await resolveTestCode('''
 import 'package:flutter/material.dart';
 main() {
   Column(
+    mainAxisAlignment: MainAxisAlignment.start,
     /*caret*/children: <Widget>[
       Text('aaa'),
       Text('bbbbbb'),
@@ -91,6 +92,7 @@
 import 'package:flutter/material.dart';
 main() {
   Column(
+    mainAxisAlignment: MainAxisAlignment.start,
     crossAxisAlignment: CrossAxisAlignment.center,
     children: <Widget>[
       Text('aaa'),
@@ -121,4 +123,64 @@
 ''');
     await assertNoAssist();
   }
+
+  Future<void> test_sort_noTrailingComma() async {
+    await resolveTestCode('''
+import 'package:flutter/material.dart';
+main() {
+  Column(
+    /*caret*/children: <Widget>[
+      Text('aaa'),
+      Text('bbbbbb'),
+      Text('ccccccccc'),
+    ],
+    crossAxisAlignment: CrossAxisAlignment.center
+  );
+}
+''');
+    await assertHasAssist('''
+import 'package:flutter/material.dart';
+main() {
+  Column(
+    crossAxisAlignment: CrossAxisAlignment.center,
+    children: <Widget>[
+      Text('aaa'),
+      Text('bbbbbb'),
+      Text('ccccccccc'),
+    ]
+  );
+}
+''');
+    assertExitPosition(after: ']');
+  }
+
+  Future<void> test_sort_trailingComma() async {
+    await resolveTestCode('''
+import 'package:flutter/material.dart';
+main() {
+  Column(
+    /*caret*/children: <Widget>[
+      Text('aaa'),
+      Text('bbbbbb'),
+      Text('ccccccccc'),
+    ],
+    crossAxisAlignment: CrossAxisAlignment.center,
+  );
+}
+''');
+    await assertHasAssist('''
+import 'package:flutter/material.dart';
+main() {
+  Column(
+    crossAxisAlignment: CrossAxisAlignment.center,
+    children: <Widget>[
+      Text('aaa'),
+      Text('bbbbbb'),
+      Text('ccccccccc'),
+    ],
+  );
+}
+''');
+    assertExitPosition(after: '],');
+  }
 }
diff --git a/pkg/analyzer_cli/lib/src/build_mode.dart b/pkg/analyzer_cli/lib/src/build_mode.dart
index 5223b4a..ec18a06 100644
--- a/pkg/analyzer_cli/lib/src/build_mode.dart
+++ b/pkg/analyzer_cli/lib/src/build_mode.dart
@@ -6,15 +6,16 @@
 import 'dart:isolate';
 import 'dart:typed_data';
 
-import 'package:analyzer/dart/analysis/context_locator.dart' as api;
 import 'package:analyzer/dart/analysis/declared_variables.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/src/analysis_options/analysis_options_provider.dart';
 import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/context/packages.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
 import 'package:analyzer/src/dart/analysis/cache.dart';
+import 'package:analyzer/src/dart/analysis/context_root.dart' as api;
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/dart/analysis/driver_based_analysis_context.dart'
     as api;
@@ -32,11 +33,12 @@
 import 'package:analyzer/src/summary2/linked_element_factory.dart';
 import 'package:analyzer/src/summary2/package_bundle_format.dart';
 import 'package:analyzer/src/summary2/reference.dart';
-import 'package:analyzer_cli/src/context_cache.dart';
+import 'package:analyzer/src/task/options.dart';
+import 'package:analyzer/src/util/file_paths.dart' as file_paths;
+import 'package:analyzer/src/workspace/bazel.dart';
 import 'package:analyzer_cli/src/driver.dart';
 import 'package:analyzer_cli/src/error_formatter.dart';
 import 'package:analyzer_cli/src/error_severity.dart';
-import 'package:analyzer_cli/src/has_context_mixin.dart';
 import 'package:analyzer_cli/src/options.dart';
 import 'package:bazel_worker/bazel_worker.dart';
 import 'package:collection/collection.dart';
@@ -81,7 +83,6 @@
     var packageBundleProvider =
         WorkerPackageBundleProvider(packageBundleCache, inputs);
     var buildMode = BuildMode(resourceProvider, options, AnalysisStats(),
-        ContextCache(resourceProvider, options, Driver.verbosePrint),
         logger: logger, packageBundleProvider: packageBundleProvider);
     await buildMode.analyze();
     AnalysisEngine.instance.clearCaches();
@@ -154,17 +155,13 @@
 }
 
 /// Analyzer used when the "--build-mode" option is supplied.
-class BuildMode with HasContextMixin {
-  @override
+class BuildMode {
   final ResourceProvider resourceProvider;
   final CommandLineOptions options;
   final AnalysisStats stats;
   final PerformanceLog logger;
   final PackageBundleProvider packageBundleProvider;
 
-  @override
-  final ContextCache contextCache;
-
   SummaryDataStore summaryDataStore;
   AnalysisOptionsImpl analysisOptions;
   Map<Uri, File> uriToFileMap;
@@ -179,7 +176,7 @@
   // May be null.
   final DependencyTracker dependencyTracker;
 
-  BuildMode(this.resourceProvider, this.options, this.stats, this.contextCache,
+  BuildMode(this.resourceProvider, this.options, this.stats,
       {PerformanceLog logger, PackageBundleProvider packageBundleProvider})
       : logger = logger ?? PerformanceLog(null),
         packageBundleProvider = packageBundleProvider ??
@@ -281,6 +278,16 @@
     });
   }
 
+  void _applyOptionsFile() {
+    analysisOptions = AnalysisOptionsImpl();
+
+    var path = options.contextBuilderOptions.defaultAnalysisOptionsFilePath;
+    var file = resourceProvider.getFile(path);
+    var provider = AnalysisOptionsProvider(sourceFactory);
+    var map = provider.getOptionsFromFile(file);
+    applyToAnalysisOptions(analysisOptions, map);
+  }
+
   /// Use [elementFactory] filled with input summaries, and link libraries
   /// in [explicitSources] to produce linked summary bytes.
   Uint8List _computeLinkedLibraries2() {
@@ -394,8 +401,7 @@
       }
     });
 
-    var rootPath =
-        options.sourceFiles.isEmpty ? null : options.sourceFiles.first;
+    var rootPath = options.sourceFiles.first;
 
     var packages = _findPackages(rootPath);
 
@@ -407,8 +413,7 @@
       ExplicitSourceResolver(uriToFileMap)
     ]);
 
-    analysisOptions =
-        createAnalysisOptionsForCommandLineOptions(options, rootPath);
+    _applyOptionsFile();
 
     var scheduler = AnalysisDriverScheduler(logger);
     analysisDriver = AnalysisDriver(
@@ -524,25 +529,23 @@
   }
 
   void _setAnalysisDriverAnalysisContext(String rootPath) {
-    if (rootPath == null) {
-      return;
-    }
-
-    var apiContextRoots = api.ContextLocator(
-      resourceProvider: resourceProvider,
-    ).locateRoots(
-      includedPaths: [rootPath],
-      excludedPaths: [],
+    rootPath = file_paths.absoluteNormalized(
+      resourceProvider.pathContext,
+      rootPath,
     );
 
-    if (apiContextRoots.isEmpty) {
-      return;
-    }
+    var workspace = BazelWorkspace.find(resourceProvider, rootPath);
+
+    var contextRoot = api.ContextRootImpl(
+      resourceProvider,
+      resourceProvider.getFolder(workspace.root),
+      workspace,
+    );
 
     analysisDriver.configure(
       analysisContext: api.DriverBasedAnalysisContext(
         resourceProvider,
-        apiContextRoots.first,
+        contextRoot,
         analysisDriver,
       ),
     );
diff --git a/pkg/analyzer_cli/lib/src/context_cache.dart b/pkg/analyzer_cli/lib/src/context_cache.dart
deleted file mode 100644
index 876239c..0000000
--- a/pkg/analyzer_cli/lib/src/context_cache.dart
+++ /dev/null
@@ -1,139 +0,0 @@
-// 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.
-
-import 'package:analyzer/dart/analysis/features.dart';
-import 'package:analyzer/file_system/file_system.dart';
-import 'package:analyzer/src/context/builder.dart';
-import 'package:analyzer/src/dart/analysis/experiments.dart';
-import 'package:analyzer/src/generated/engine.dart';
-import 'package:analyzer_cli/src/options.dart';
-import 'package:path/path.dart' as path;
-import 'package:pub_semver/pub_semver.dart';
-
-/// Cache of [AnalysisOptionsImpl] objects that correspond to directories
-/// with analyzed files, used to reduce searching for `analysis_options.yaml`
-/// files.
-class ContextCache {
-  final ResourceProvider resourceProvider;
-  final CommandLineOptions clOptions;
-  final void Function(String) verbosePrint;
-
-  /// A mapping from normalized paths (currently, directories) to cache entries
-  /// which include builder, analysis_options paths, and [AnalysisOptionImpl]s.
-  final Map<String, ContextCacheEntry> _byDirectory = {};
-
-  ContextCache(this.resourceProvider, this.clOptions, this.verbosePrint);
-
-  /// Look up info about a context from the cache. You can pass in any [path],
-  /// and it will try to provide an existing [ContextCacheEntry] that is
-  /// suitable for that [path] if one exists.
-  ContextCacheEntry forSource(String path) {
-    path = _normalizeSourcePath(path);
-    return _byDirectory.putIfAbsent(path, () {
-      final builder = ContextBuilder(resourceProvider, null, null,
-          options: clOptions.contextBuilderOptions);
-      return ContextCacheEntry(builder, path, clOptions, verbosePrint);
-    });
-  }
-
-  /// Cheaply normalize source paths so we can increase cache performance.
-  /// Getting the location of an analysis_options.yaml file for a given source
-  /// can be expensive, so we want to reduce extra lookups where possible. We
-  /// know that two files in the same directory share an analysis options file,
-  /// so that's the normalization we perform currently. However, this could be
-  /// any form of performance-increasing cache key normalization.
-  String _normalizeSourcePath(String sourcePath) {
-    if (!resourceProvider.pathContext.isAbsolute(sourcePath)) {
-      // TODO(mfairhurst) Use resourceProvider.pathContext.absolute(). For the
-      // moment, we get an issues where pathContext.current is `.`, which causes
-      // pathContext.absolute() to produce `./foo` instead of `/absolute/foo`.
-      sourcePath = path.absolute(sourcePath);
-    }
-
-    sourcePath = resourceProvider.pathContext.normalize(sourcePath);
-
-    // Prepare the directory which is, or contains, the context root.
-    if (resourceProvider.getFolder(sourcePath).exists) {
-      return sourcePath;
-    }
-
-    return resourceProvider.pathContext.dirname(sourcePath);
-  }
-}
-
-/// Each entry of the [ContextCache] caches three things: the [ContextBuilder],
-/// the analysis_options.yaml path of the context, and the [AnalysisOptionsImpl]
-/// of the context.
-class ContextCacheEntry {
-  final CommandLineOptions clOptions;
-  final ContextBuilder builder;
-  final String requestedSourceDirectory;
-  final void Function(String) verbosePrint;
-
-  AnalysisOptionsImpl _analysisOptions;
-  String _analysisRoot;
-
-  ContextCacheEntry(this.builder, this.requestedSourceDirectory, this.clOptions,
-      this.verbosePrint);
-
-  /// Get the fully parsed [AnalysisOptionsImpl] for this entry.
-  AnalysisOptionsImpl get analysisOptions =>
-      _analysisOptions ??= _getAnalysisOptions();
-
-  /// Find the root path from which excludes should be considered due to where
-  /// the analysis_options.yaml was defined.
-  String get analysisRoot => _analysisRoot ??= _getAnalysisRoot();
-
-  void _buildContextFeatureSet(AnalysisOptionsImpl analysisOptions) {
-    var featureSet = FeatureSet.fromEnableFlags2(
-      sdkLanguageVersion: ExperimentStatus.currentVersion,
-      flags: clOptions.enabledExperiments,
-    );
-
-    analysisOptions.contextFeatures = featureSet;
-
-    if (clOptions.defaultLanguageVersion != null) {
-      var nonPackageLanguageVersion = Version.parse(
-        clOptions.defaultLanguageVersion + '.0',
-      );
-      analysisOptions.nonPackageLanguageVersion = nonPackageLanguageVersion;
-      analysisOptions.nonPackageFeatureSet = FeatureSet.latestLanguageVersion()
-          .restrictToVersion(nonPackageLanguageVersion);
-    }
-  }
-
-  /// The actual calculation to get the [AnalysisOptionsImpl], with no caching.
-  /// This should not be used except behind the getter which caches this result
-  /// automatically.
-  AnalysisOptionsImpl _getAnalysisOptions() {
-    var workspace = ContextBuilder.createWorkspace(
-      resourceProvider: builder.resourceProvider,
-      options: builder.builderOptions,
-      rootPath: requestedSourceDirectory,
-    );
-    var contextOptions = builder.getAnalysisOptions(
-        requestedSourceDirectory, workspace,
-        verbosePrint: clOptions.verbose ? verbosePrint : null);
-
-    _buildContextFeatureSet(contextOptions);
-    contextOptions.hint = !clOptions.disableHints;
-    return contextOptions;
-  }
-
-  /// The actual calculation to get the analysis root, with no caching. This
-  /// should not be used except behind the getter which caches this result
-  /// automatically.
-  String _getAnalysisRoot() {
-    // The analysis yaml defines the root, if it exists.
-    var analysisOptionsPath = builder
-        .getOptionsFile(requestedSourceDirectory, forceSearch: true)
-        ?.path;
-
-    if (analysisOptionsPath == null) {
-      return requestedSourceDirectory;
-    }
-
-    return path.dirname(analysisOptionsPath);
-  }
-}
diff --git a/pkg/analyzer_cli/lib/src/driver.dart b/pkg/analyzer_cli/lib/src/driver.dart
index 2767510..f5d7076 100644
--- a/pkg/analyzer_cli/lib/src/driver.dart
+++ b/pkg/analyzer_cli/lib/src/driver.dart
@@ -35,10 +35,8 @@
 import 'package:analyzer_cli/src/analyzer_impl.dart';
 import 'package:analyzer_cli/src/batch_mode.dart';
 import 'package:analyzer_cli/src/build_mode.dart';
-import 'package:analyzer_cli/src/context_cache.dart';
 import 'package:analyzer_cli/src/error_formatter.dart';
 import 'package:analyzer_cli/src/error_severity.dart';
-import 'package:analyzer_cli/src/has_context_mixin.dart';
 import 'package:analyzer_cli/src/options.dart';
 import 'package:analyzer_cli/src/perf_report.dart';
 import 'package:analyzer_cli/starter.dart' show CommandLineStarter;
@@ -60,12 +58,9 @@
   return linterNode is YamlMap && getValue(linterNode, 'rules') != null;
 }
 
-class Driver with HasContextMixin implements CommandLineStarter {
+class Driver implements CommandLineStarter {
   static final ByteStore analysisDriverMemoryByteStore = MemoryByteStore();
 
-  @override
-  ContextCache contextCache;
-
   _AnalysisContextProvider _analysisContextProvider;
   DriverBasedAnalysisContext analysisContext;
 
@@ -78,7 +73,6 @@
   int _analyzedFileCount = 0;
 
   /// The resource provider used to access the file system.
-  @override
   final ResourceProvider resourceProvider = PhysicalResourceProvider.INSTANCE;
 
   /// Collected analysis statistics.
@@ -400,9 +394,7 @@
       await workerLoop.run();
       return ErrorSeverity.NONE;
     } else {
-      return await BuildMode(resourceProvider, options, stats,
-              ContextCache(resourceProvider, options, verbosePrint))
-          .analyze();
+      return await BuildMode(resourceProvider, options, stats).analyze();
     }
   }
 
diff --git a/pkg/analyzer_cli/lib/src/has_context_mixin.dart b/pkg/analyzer_cli/lib/src/has_context_mixin.dart
deleted file mode 100644
index 554deca..0000000
--- a/pkg/analyzer_cli/lib/src/has_context_mixin.dart
+++ /dev/null
@@ -1,40 +0,0 @@
-// 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.
-
-import 'package:analyzer/error/error.dart';
-import 'package:analyzer/file_system/file_system.dart';
-import 'package:analyzer/src/generated/engine.dart';
-import 'package:analyzer_cli/src/context_cache.dart';
-import 'package:analyzer_cli/src/options.dart';
-
-abstract class HasContextMixin {
-  ContextCache get contextCache;
-  ResourceProvider get resourceProvider;
-
-  /// Based on the command line options, performantly get cached analysis
-  /// options for the context.
-  AnalysisOptionsImpl createAnalysisOptionsForCommandLineOptions(
-      CommandLineOptions options, String source) {
-    if (options.analysisOptionsFile != null) {
-      var file = resourceProvider.getFile(options.analysisOptionsFile);
-      if (!file.exists) {
-        printAndFail('Options file not found: ${options.analysisOptionsFile}',
-            exitCode: ErrorSeverity.ERROR.ordinal);
-      }
-    }
-
-    return getContextInfo(options, source).analysisOptions;
-  }
-
-  /// Based on the [CommandLineOptions], and a specific [Source] within those
-  /// options if any are specified, performantly get cached info about the
-  /// context.
-  ContextCacheEntry getContextInfo(CommandLineOptions options, String source) {
-    if (options.sourceFiles.isEmpty) {
-      return contextCache.forSource(resourceProvider.pathContext.current);
-    }
-
-    return contextCache.forSource(source);
-  }
-}
diff --git a/pkg/analyzer_cli/test/driver_test.dart b/pkg/analyzer_cli/test/driver_test.dart
index 6d818d6..9cdec75 100644
--- a/pkg/analyzer_cli/test/driver_test.dart
+++ b/pkg/analyzer_cli/test/driver_test.dart
@@ -413,6 +413,7 @@
   Future<void> _withTempDir(Future<void> Function() f) async {
     await withTempDirAsync((tempDir) async {
       this.tempDir = tempDir;
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
       await f();
     });
   }
@@ -422,20 +423,27 @@
 class BuildModeTest extends AbstractBuildModeTest {
   Future<void> test_buildLinked() async {
     await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
+
+      var inputUri = 'package:dart.my/a.dart';
+      var inputPath = path.join(tempDir, 'dart', 'my', 'lib', 'a.dart');
+      (File(inputPath)..parent.createSync(recursive: true))
+          .writeAsStringSync('');
+
       var outputPath = path.join(tempDir, 'test_file.dart.sum');
-      await _doDrive(path.join('data', 'test_file.dart'), additionalArgs: [
+      await _doDrive(inputPath, fileUri: inputUri, additionalArgs: [
         '--build-summary-only',
         '--build-summary-output=$outputPath'
       ]);
+
       var output = File(outputPath);
       expect(output.existsSync(), isTrue);
       var bundle = PackageBundleReader(await output.readAsBytes());
-      var testFileUri = 'file:///test_file.dart';
 
-      expect(_linkedLibraryUriList(bundle), [testFileUri]);
+      expect(_linkedLibraryUriList(bundle), [inputUri]);
       expect(
-        _linkedLibraryUnitUriList(bundle, testFileUri),
-        [testFileUri],
+        _linkedLibraryUnitUriList(bundle, inputUri),
+        [inputUri],
       );
 
       expect(exitCode, 0);
@@ -444,6 +452,7 @@
 
   Future<void> test_buildLinked_invalidPartUri() async {
     await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
       var aDart = path.join(tempDir, 'a.dart');
 
       var aUri = 'package:aaa/a.dart';
@@ -465,19 +474,35 @@
   }
 
   Future<void> test_buildSuppressExitCode_fail_whenFileNotFound() async {
-    await _doDrive(path.join('data', 'non_existent_file.dart'),
-        additionalArgs: ['--build-suppress-exit-code']);
-    expect(exitCode, isNot(0));
+    await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
+
+      await _doDrive(path.join(tempDir, 'non_existent_file.dart'),
+          additionalArgs: ['--build-suppress-exit-code']);
+      expect(exitCode, isNot(0));
+    });
   }
 
   Future<void> test_buildSuppressExitCode_success_evenIfHasError() async {
-    await _doDrive(path.join('data', 'file_with_error.dart'),
-        additionalArgs: ['--build-suppress-exit-code']);
-    expect(exitCode, 0);
+    await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
+
+      var inputUri = 'package:dart.my/a.dart';
+      var inputPath = path.join(tempDir, 'dart', 'my', 'lib', 'a.dart');
+      (File(inputPath)..parent.createSync(recursive: true))
+          .writeAsStringSync('error');
+
+      await _doDrive(inputPath, fileUri: inputUri, additionalArgs: [
+        '--build-suppress-exit-code',
+      ]);
+      expect(exitCode, 0);
+    });
   }
 
   Future<void> test_consumeLinked() async {
     await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
+
       var aDart = path.join(tempDir, 'a.dart');
       var bDart = path.join(tempDir, 'b.dart');
       var cDart = path.join(tempDir, 'c.dart');
@@ -542,6 +567,8 @@
 
   Future<void> test_error_notUriPipePath() async {
     await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
+
       var testDart = path.join(tempDir, 'test.dart');
       File(testDart).writeAsStringSync('var v = 42;');
 
@@ -556,10 +583,20 @@
   }
 
   Future<void> test_fail_whenHasError() async {
-    await _doDrive(path.join('data', 'file_with_error.dart'));
-    expect(exitCode, isNot(0));
+    await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
+
+      var inputUri = 'package:my/with_error.dart';
+      var inputPath = path.join(tempDir, 'my', 'lib', 'with_error.dart');
+      (File(inputPath)..parent.createSync(recursive: true))
+          .writeAsStringSync('error');
+
+      await _doDrive(inputPath, fileUri: inputUri);
+      expect(exitCode, isNot(0));
+    });
   }
 
+  @FailingTest(reason: 'Why do we support this case?')
   Future<void> test_noInputs() async {
     await withTempDirAsync((tempDir) async {
       var outputPath = path.join(tempDir, 'test.sum');
@@ -580,15 +617,27 @@
   }
 
   Future<void> test_noStatistics() async {
-    await _doDrive(path.join('data', 'test_file.dart'));
-    // Should not print statistics summary.
-    expect(outSink.toString(), isEmpty);
-    expect(errorSink.toString(), isEmpty);
-    expect(exitCode, 0);
+    await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
+
+      var inputUri = 'package:my/a.dart';
+      var inputPath = path.join(tempDir, 'my', 'lib', 'a.dart');
+      (File(inputPath)..parent.createSync(recursive: true))
+          .writeAsStringSync('class A {}');
+
+      await _doDrive(inputPath, fileUri: inputUri);
+
+      // Should not print statistics summary.
+      expect(outSink.toString(), isEmpty);
+      expect(errorSink.toString(), isEmpty);
+      expect(exitCode, 0);
+    });
   }
 
   Future<void> test_onlyErrors_partFirst() async {
     await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
+
       var aDart = path.join(tempDir, 'a.dart');
       var bDart = path.join(tempDir, 'b.dart');
 
@@ -616,6 +665,8 @@
 
   Future<void> test_packageConfig_packagesOptions() async {
     await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
+
       var packagesPath = path.join(tempDir, 'aaa.packages');
 
       var aaaRoot = path.join(tempDir, 'packages', 'aaa');
@@ -658,6 +709,8 @@
 
   Future<void> test_packageConfig_relativeToFile() async {
     await withTempDirAsync((tempDir) async {
+      File(path.join(tempDir, 'WORKSPACE')).writeAsStringSync('');
+
       var packagesPath = path.join(tempDir, '.dart_tool/package_config.json');
 
       var aaaRoot = path.join(tempDir, 'packages', 'aaa');
diff --git a/pkg/dev_compiler/lib/src/compiler/module_builder.dart b/pkg/dev_compiler/lib/src/compiler/module_builder.dart
index 847185d..04b15cc 100644
--- a/pkg/dev_compiler/lib/src/compiler/module_builder.dart
+++ b/pkg/dev_compiler/lib/src/compiler/module_builder.dart
@@ -96,6 +96,27 @@
   }
 }
 
+/// Transforms an ES6 [function] into a given module [format].
+///
+/// If the format is [ModuleFormat.es6] this will return [function] unchanged.
+///
+/// Because JS ASTs are immutable the resulting function will share as much
+/// structure as possible with the original. The transformation is a shallow one
+/// that affects the [ImportDeclaration]s from [items].
+///
+/// Returns a new function that combines all statements from tranformed imports
+/// from [items] and the body of the [function].
+Fun transformFunctionModuleFormat(
+    List<ModuleItem> items, Fun function, ModuleFormat format) {
+  switch (format) {
+    case ModuleFormat.amd:
+      return AmdModuleBuilder().buildFunctionWithImports(items, function);
+    default:
+      throw UnsupportedError(
+          'Incremental build does not support $format module format');
+  }
+}
+
 /// Base class for compiling ES6 modules into various ES5 module patterns.
 ///
 /// This is a helper class for utilities and state that is shared by several
@@ -107,11 +128,16 @@
   final statements = <Statement>[];
 
   /// Collect [imports], [exports] and [statements] from the ES6 [module].
+  void visitProgram(Program module) {
+    visitModuleItems(module.body);
+  }
+
+  /// Collect [imports], [exports] and [statements] from the ES6 [items].
   ///
   /// For exports, this will also add their body to [statements] in the
   /// appropriate position.
-  void visitProgram(Program module) {
-    for (var item in module.body) {
+  void visitModuleItems(List<ModuleItem> items) {
+    for (var item in items) {
       if (item is ImportDeclaration) {
         visitImportDeclaration(item);
       } else if (item is ExportDeclaration) {
@@ -137,6 +163,12 @@
   void visitStatement(Statement node) {
     statements.add(node);
   }
+
+  void clear() {
+    imports.clear();
+    exports.clear();
+    statements.clear();
+  }
 }
 
 /// Generates modules for with our DDC `dart_library.js` loading mechanism.
@@ -260,31 +292,43 @@
 class AmdModuleBuilder extends _ModuleBuilder {
   AmdModuleBuilder();
 
-  Program build(Program module) {
-    var importStatements = <Statement>[];
+  /// Build a module variable definition for [import].
+  static Statement buildLoadModule(
+          Identifier moduleVar, ImportDeclaration import) =>
+      js.statement('const # = require(#);', [moduleVar, import.from]);
 
-    // Collect imports/exports/statements.
-    visitProgram(module);
+  /// Build library variable definitions for all libraries from [import].
+  static List<Statement> buildImports(
+      Identifier moduleVar, ImportDeclaration import) {
+    var items = <Statement>[];
 
-    var dependencies = <LiteralString>[];
-    var fnParams = <Parameter>[];
+    for (var importName in import.namedImports) {
+      // import * is not emitted by the compiler, so we don't handle it here.
+      assert(!importName.isStar);
+      var asName = importName.asName ?? importName.name;
+      items.add(js.statement(
+          'const # = #.#', [asName, moduleVar, importName.name.name]));
+    }
+    return items;
+  }
+
+  /// Group libraries from [imports] by modules.
+  static Map<Identifier, ImportDeclaration> _collectModuleImports(
+      List<ImportDeclaration> imports) {
+    var result = <Identifier, ImportDeclaration>{};
     for (var import in imports) {
       // TODO(jmesserly): we could use destructuring once Atom supports it.
       var moduleVar =
           TemporaryId(pathToJSIdentifier(import.from.valueWithoutQuotes));
-      fnParams.add(moduleVar);
-      dependencies.add(import.from);
 
-      // TODO(jmesserly): optimize for the common case of a single import.
-      for (var importName in import.namedImports) {
-        // import * is not emitted by the compiler, so we don't handle it here.
-        assert(!importName.isStar);
-        var asName = importName.asName ?? importName.name;
-        importStatements.add(js.statement(
-            'const # = #.#', [asName, moduleVar, importName.name.name]));
-      }
+      result[moduleVar] = import;
     }
-    statements.insertAll(0, importStatements);
+    return result;
+  }
+
+  /// Build statements for [exports].
+  static List<Statement> buildExports(List<ExportDeclaration> exports) {
+    var items = <Statement>[];
 
     if (exports.isNotEmpty) {
       var exportedProps = <Property>[];
@@ -297,9 +341,59 @@
           exportedProps.add(Property(js.string(alias.name), name.name));
         }
       }
-      statements.add(js.comment('Exports:'));
-      statements.add(Return(ObjectInitializer(exportedProps, multiline: true)));
+      items.add(js.comment('Exports:'));
+      items.add(Return(ObjectInitializer(exportedProps, multiline: true)));
     }
+    return items;
+  }
+
+  /// Build function body with all necessary imports included.
+  ///
+  /// Used for the top level syntetic function generated during expression
+  /// compilation, in order to include all the context needed for evaluation
+  /// inside it.
+  ///
+  /// Returns a new function that combines all statements from tranformed
+  /// imports from [items] and the body of the [function].
+  Fun buildFunctionWithImports(List<ModuleItem> items, Fun function) {
+    clear();
+    visitModuleItems(items);
+
+    var moduleImports = _collectModuleImports(imports);
+    var importStatements = <Statement>[];
+
+    moduleImports.forEach((moduleVar, import) {
+      importStatements.add(buildLoadModule(moduleVar, import));
+      importStatements.addAll(buildImports(moduleVar, import));
+    });
+
+    return Fun(
+      function.params,
+      Block([...importStatements, ...statements, ...function.body.statements]),
+    );
+  }
+
+  Program build(Program module) {
+    // Collect imports/exports/statements.
+    visitProgram(module);
+
+    var moduleImports = _collectModuleImports(imports);
+    var importStatements = <Statement>[];
+
+    var fnParams = moduleImports.keys.toList();
+    var dependencies =
+        moduleImports.values.map((import) => import.from).toList();
+
+    moduleImports.forEach((moduleVar, import) {
+      importStatements.addAll(buildImports(moduleVar, import));
+    });
+
+    // Prepend import statetements.
+    statements.insertAll(0, importStatements);
+
+    // Append export statements.
+    statements.addAll(buildExports(exports));
+
     var resultModule = NamedFunction(
         loadFunctionIdentifier(module.name),
         js.fun("function(#) { 'use strict'; #; }", [fnParams, statements]),
diff --git a/pkg/dev_compiler/lib/src/compiler/module_containers.dart b/pkg/dev_compiler/lib/src/compiler/module_containers.dart
index 2e03a63..0040d60 100644
--- a/pkg/dev_compiler/lib/src/compiler/module_containers.dart
+++ b/pkg/dev_compiler/lib/src/compiler/module_containers.dart
@@ -8,6 +8,9 @@
 import '../js_ast/js_ast.dart' as js_ast;
 import '../js_ast/js_ast.dart' show js;
 
+/// Defines how to emit a value of a table
+typedef _emitValue<K> = js_ast.Expression Function(K, ModuleItemData);
+
 /// Represents a top-level property hoisted to a top-level object.
 class ModuleItemData {
   /// The container that holds this module item in the emitted JS.
@@ -39,34 +42,39 @@
   /// Name of the container in the emitted JS.
   String name;
 
-  /// Indicates if this table is being used in an incremental context (such as
-  /// during expression evaluation).
-  ///
-  /// Set by `emitFunctionIncremental` in kernel/compiler.dart.
-  bool incrementalMode = false;
-
   /// Refers to the latest container if this container is sharded.
   js_ast.Identifier containerId;
 
-  /// Refers to the aggregated entrypoint into this container.
-  ///
-  /// Should only be accessed during expression evaluation since lookups are
-  /// deoptimized in V8..
-  js_ast.Identifier aggregatedContainerId;
-
   final Map<K, ModuleItemData> moduleItems = {};
 
+  /// Incremental mode used for expression compilation
+  bool _incrementalMode = false;
+
+  /// Items accessed during incremental mode
+  final Set<K> incrementalModuleItems = {};
+
+  /// Indicates if this table is being used in an incremental context.
+  ///
+  /// Used during expression evaluation.
+  /// Set by `emitFunctionIncremental` in kernel/compiler.dart.
+  bool get incrementalMode => _incrementalMode;
+
+  /// Sets the container to incremental mode.
+  ///
+  /// Used during expression evaluating so only referenced items
+  /// will be emitted in a generated function.
+  ///
+  /// Note: the container cannot revert to non-incremental mode.
+  void setIncrementalMode() {
+    incrementalModuleItems.clear();
+    _incrementalMode = true;
+  }
+
   /// Holds keys that will not be emitted when calling [emit].
   final Set<K> _noEmit = {};
 
-  /// Creates a container with a name, ID, and incremental ID used for
-  /// expression evaluation.
-  ///
-  /// If [aggregatedId] is null, the container is not sharded, so the
-  /// containerId is safe to use during eval.
-  ModuleItemContainer._(
-      this.name, this.containerId, js_ast.Identifier aggregatedId)
-      : aggregatedContainerId = aggregatedId ?? containerId;
+  /// Creates a container with a name, ID
+  ModuleItemContainer._(this.name, this.containerId);
 
   /// Creates an automatically sharding container backed by JS Objects.
   factory ModuleItemContainer.asObject(String name,
@@ -107,15 +115,17 @@
     _noEmit.add(key);
   }
 
+  void setEmitIfIncremental(K key) {
+    if (incrementalMode) {
+      incrementalModuleItems.add(key);
+    }
+  }
+
   /// Emit the container declaration/initializer, using multiple statements if
   /// necessary.
-  List<js_ast.Statement> emit();
-
-  /// Emit the container declaration/initializer incrementally.
   ///
-  /// Used during expression evaluation. Appends all newly added types to the
-  /// aggregated container.
-  List<js_ast.Statement> emitIncremental();
+  /// Uses [emitValue] to emit the values in the table.
+  List<js_ast.Statement> emit({_emitValue<K> emitValue});
 }
 
 /// Associates a [K] with a container-unique JS key and arbitrary JS value.
@@ -142,8 +152,7 @@
   String Function(K) keyToString;
 
   ModuleItemObjectContainer(String name, this.keyToString)
-      : super._(
-            name, js_ast.TemporaryId(name), js_ast.Identifier('${name}\$Eval'));
+      : super._(name, js_ast.TemporaryId(name));
 
   @override
   void operator []=(K key, js_ast.Expression value) {
@@ -170,53 +179,33 @@
 
   @override
   js_ast.Expression access(K key) {
-    var id = incrementalMode ? aggregatedContainerId : moduleItems[key].id;
+    var id = moduleItems[key].id;
     return js.call('#.#', [id, moduleItems[key].jsKey]);
   }
 
   @override
-  List<js_ast.Statement> emit() {
+  List<js_ast.Statement> emit({_emitValue<K> emitValue}) {
     var containersToProperties = <js_ast.Identifier, List<js_ast.Property>>{};
     moduleItems.forEach((k, v) {
-      if (_noEmit.contains(k)) return;
+      if (!incrementalMode && _noEmit.contains(k)) return;
+      if (incrementalMode && !incrementalModuleItems.contains(k)) return;
+
       if (!containersToProperties.containsKey(v.id)) {
         containersToProperties[v.id] = <js_ast.Property>[];
       }
-      containersToProperties[v.id].add(js_ast.Property(v.jsKey, v.jsValue));
+      containersToProperties[v.id].add(js_ast.Property(
+          v.jsKey, emitValue == null ? v.jsValue : emitValue(k, v)));
     });
 
-    // Emit a self-reference for the next container so V8 does not optimize it
-    // away. Required for expression evaluation.
-    if (containersToProperties[containerId] == null) {
-      containersToProperties[containerId] = [
-        js_ast.Property(
-            js_ast.LiteralString('_'), js.call('() => #', [containerId]))
-      ];
-    }
+    if (containersToProperties.isEmpty) return [];
+
     var statements = <js_ast.Statement>[];
-    var aggregatedContainers = <js_ast.Expression>[];
     containersToProperties.forEach((containerId, properties) {
       var containerObject = js_ast.ObjectInitializer(properties,
           multiline: properties.length > 1);
       statements.add(js.statement('var # = #', [containerId, containerObject]));
-      aggregatedContainers.add(js.call('#', [containerId]));
     });
-    // Create an aggregated access point over all containers for eval.
-    statements.add(js.statement('var # = Object.assign({_ : () => #}, #)',
-        [aggregatedContainerId, aggregatedContainerId, aggregatedContainers]));
-    return statements;
-  }
 
-  /// Appends all newly added types to the most recent container.
-  @override
-  List<js_ast.Statement> emitIncremental() {
-    assert(incrementalMode);
-    var statements = <js_ast.Statement>[];
-    moduleItems.forEach((k, v) {
-      if (_noEmit.contains(k)) return;
-      statements.add(js
-          .statement('#[#] = #', [aggregatedContainerId, v.jsKey, v.jsValue]));
-    });
     return statements;
   }
 }
@@ -232,7 +221,7 @@
 /// ```
 class ModuleItemArrayContainer<K> extends ModuleItemContainer<K> {
   ModuleItemArrayContainer(String name)
-      : super._(name, js_ast.TemporaryId(name), null);
+      : super._(name, js_ast.TemporaryId(name));
 
   @override
   void operator []=(K key, js_ast.Expression value) {
@@ -246,23 +235,26 @@
 
   @override
   js_ast.Expression access(K key) {
-    var id = incrementalMode ? aggregatedContainerId : containerId;
+    var id = containerId;
     return js.call('#[#]', [id, moduleItems[key].jsKey]);
   }
 
   @override
-  List<js_ast.Statement> emit() {
+  List<js_ast.Statement> emit({_emitValue<K> emitValue}) {
     var properties = List<js_ast.Expression>.filled(length, null);
 
     // If the entire array holds just one value, generate a short initializer.
     var valueSet = <js_ast.Expression>{};
     moduleItems.forEach((k, v) {
-      if (_noEmit.contains(k)) return;
+      if (!incrementalMode && _noEmit.contains(k)) return;
+      if (incrementalMode && !incrementalModuleItems.contains(k)) return;
       valueSet.add(v.jsValue);
       properties[int.parse((v.jsKey as js_ast.LiteralNumber).value)] =
-          v.jsValue;
+          emitValue == null ? v.jsValue : emitValue(k, v);
     });
 
+    if (valueSet.isEmpty) return [];
+
     if (valueSet.length == 1 && moduleItems.length > 1) {
       return [
         js.statement('var # = Array(#).fill(#)', [
@@ -281,16 +273,4 @@
       ])
     ];
   }
-
-  @override
-  List<js_ast.Statement> emitIncremental() {
-    assert(incrementalMode);
-    var statements = <js_ast.Statement>[];
-    moduleItems.forEach((k, v) {
-      if (_noEmit.contains(k)) return;
-      statements.add(js
-          .statement('#[#] = #', [aggregatedContainerId, v.jsKey, v.jsValue]));
-    });
-    return statements;
-  }
 }
diff --git a/pkg/dev_compiler/lib/src/compiler/shared_compiler.dart b/pkg/dev_compiler/lib/src/compiler/shared_compiler.dart
index 363ff0b..d83b346 100644
--- a/pkg/dev_compiler/lib/src/compiler/shared_compiler.dart
+++ b/pkg/dev_compiler/lib/src/compiler/shared_compiler.dart
@@ -30,6 +30,9 @@
   final _symbolContainer = ModuleItemContainer<js_ast.Identifier>.asObject('S',
       keyToString: (js_ast.Identifier i) => '${i.name}');
 
+  ModuleItemContainer<js_ast.Identifier> get symbolContainer =>
+      _symbolContainer;
+
   /// Extension member symbols for adding Dart members to JS types.
   ///
   /// These are added to the [extensionSymbolsModule]; see that field for more
@@ -43,6 +46,47 @@
   /// Imported libraries, and the temporaries used to refer to them.
   final _imports = <Library, js_ast.TemporaryId>{};
 
+  /// Incremental mode for expression compilation.
+  ///
+  /// If set to true, triggers emitting tall used ypes, symbols, libraries,
+  /// constants, urs inside the generated function.
+  bool _incrementalMode = false;
+
+  @protected
+  bool get incrementalMode => _incrementalMode;
+
+  /// Set incremental mode for one expression compilation.
+  ///
+  /// Sets all tables and internal structures to incremental mode so
+  /// only referenced items will be emitted in a generated function.
+  ///
+  /// Note: the compiler cannot revert to non-incremental mode.
+  @protected
+  void setIncrementalMode() {
+    incrementalModules.clear();
+    _privateNames.clear();
+    symbolContainer.setIncrementalMode();
+    _incrementalMode = true;
+  }
+
+  /// Modules and libraries accessed during compilation in incremental mode.
+  @protected
+  final Map<String, Set<String>> incrementalModules = {};
+
+  @protected
+  void setEmitIfIncrementalLibrary(Library library) {
+    if (incrementalMode && library != null) {
+      setEmitIfIncremental(libraryToModule(library), jsLibraryName(library));
+    }
+  }
+
+  @protected
+  void setEmitIfIncremental(String module, String library) {
+    if (incrementalMode && library != null) {
+      incrementalModules.putIfAbsent(module, () => {}).add(library);
+    }
+  }
+
   /// The identifier used to reference DDC's core "dart:_runtime" library from
   /// generated JS code, typically called "dart" e.g. `dart.dcall`.
   js_ast.Identifier runtimeModule;
@@ -220,8 +264,10 @@
   ///     dart.asInt(<expr>)
   ///
   @protected
-  js_ast.Expression runtimeCall(String code, [List<Object> args]) =>
-      js.call('#.$code', <Object>[runtimeModule, ...?args]);
+  js_ast.Expression runtimeCall(String code, [List<Object> args]) {
+    setEmitIfIncremental(libraryToModule(coreLibrary), runtimeModule.name);
+    return js.call('#.$code', <Object>[runtimeModule, ...?args]);
+  }
 
   /// Calls [runtimeCall] and uses `toStatement()` to convert the resulting
   /// expression into a statement.
@@ -276,7 +322,13 @@
     }
 
     var privateNames = _privateNames.putIfAbsent(library, () => HashMap());
-    return privateNames.putIfAbsent(name, initPrivateNameSymbol);
+    var symbolId = privateNames.putIfAbsent(name, initPrivateNameSymbol);
+
+    setEmitIfIncrementalLibrary(library);
+    setEmitIfIncremental(libraryToModule(coreLibrary), runtimeModule.name);
+    _symbolContainer.setEmitIfIncremental(symbolId);
+
+    return symbolId;
   }
 
   /// Emits a private name JS Symbol for [memberName] unique to a Dart
@@ -445,7 +497,6 @@
           .statement('var # = Object.create(#.library)', [id, runtimeModule]));
       exports.add(js_ast.NameSpecifier(id));
     }
-
     items.add(js_ast.ExportDeclaration(js_ast.ExportClause(exports)));
 
     if (isBuildingSdk) {
@@ -469,6 +520,8 @@
 
   /// Returns the canonical name to refer to the Dart library.
   js_ast.Identifier emitLibraryName(Library library) {
+    setEmitIfIncrementalLibrary(library);
+
     // Avoid adding the dart:_runtime to _imports when our runtime unit tests
     // import it explicitly. It will always be implicitly imported.
     if (isSdkInternalRuntime(library)) return runtimeModule;
@@ -479,12 +532,10 @@
             library, () => js_ast.TemporaryId(jsLibraryName(library)));
   }
 
-  /// Emits imports and extension methods into [items].
+  /// Emits imports into [items].
   @protected
-  void emitImportsAndExtensionSymbols(List<js_ast.ModuleItem> items,
-      {bool forceExtensionSymbols = false}) {
+  void emitImports(List<js_ast.ModuleItem> items) {
     var modules = <String, List<Library>>{};
-
     for (var import in _imports.keys) {
       modules.putIfAbsent(libraryToModule(import), () => []).add(import);
     }
@@ -493,33 +544,57 @@
     if (!_libraries.containsKey(coreLibrary)) {
       coreModuleName = libraryToModule(coreLibrary);
     }
+
     modules.forEach((module, libraries) {
-      // Generate import directives.
-      //
-      // Our import variables are temps and can get renamed. Since our renaming
-      // is integrated into js_ast, it is aware of this possibility and will
-      // generate an "as" if needed. For example:
-      //
-      //     import {foo} from 'foo';         // if no rename needed
-      //     import {foo as foo$} from 'foo'; // if rename was needed
-      //
-      var imports = libraries.map((library) {
-        var alias = jsLibraryAlias(library);
-        if (alias != null) {
-          var aliasId = js_ast.TemporaryId(alias);
-          return js_ast.NameSpecifier(aliasId, asName: _imports[library]);
+      if (!incrementalMode || incrementalModules.containsKey(module)) {
+        var usedLibraries = incrementalModules[module];
+
+        // Generate import directives.
+        //
+        // Our import variables are temps and can get renamed. Since our renaming
+        // is integrated into js_ast, it is aware of this possibility and will
+        // generate an "as" if needed. For example:
+        //
+        //     import {foo} from 'foo';         // if no rename needed
+        //     import {foo as foo$} from 'foo'; // if rename was needed
+        //
+        var imports = <js_ast.NameSpecifier>[];
+        for (var library in libraries) {
+          if (!incrementalMode ||
+              usedLibraries.contains(jsLibraryName(library))) {
+            var alias = jsLibraryAlias(library);
+            if (alias != null) {
+              var aliasId = js_ast.TemporaryId(alias);
+              imports.add(
+                  js_ast.NameSpecifier(aliasId, asName: _imports[library]));
+            } else {
+              imports.add(js_ast.NameSpecifier(_imports[library]));
+            }
+          }
         }
-        return js_ast.NameSpecifier(_imports[library]);
-      }).toList();
-      if (module == coreModuleName) {
-        imports.add(js_ast.NameSpecifier(runtimeModule));
-        imports.add(js_ast.NameSpecifier(extensionSymbolsModule));
+
+        if (module == coreModuleName) {
+          if (!incrementalMode || usedLibraries.contains(runtimeModule.name)) {
+            imports.add(js_ast.NameSpecifier(runtimeModule));
+          }
+          if (!incrementalMode ||
+              usedLibraries.contains(extensionSymbolsModule.name)) {
+            imports.add(js_ast.NameSpecifier(extensionSymbolsModule));
+          }
+        }
+
+        if (!incrementalMode || imports.isNotEmpty) {
+          items.add(js_ast.ImportDeclaration(
+              namedImports: imports, from: js.string(module, "'")));
+        }
       }
-
-      items.add(js_ast.ImportDeclaration(
-          namedImports: imports, from: js.string(module, "'")));
     });
+  }
 
+  /// Emits extension methods into [items].
+  @protected
+  void emitExtensionSymbols(List<js_ast.ModuleItem> items,
+      {bool forceExtensionSymbols = false}) {
     // Initialize extension symbols
     _extensionSymbols.forEach((name, id) {
       js_ast.Expression value =
@@ -530,16 +605,84 @@
         value = js.call(
             '# || (# = Symbol(#))', [value, value, js.string('dartx.$name')]);
       }
-      if (!_symbolContainer.canEmit(id)) {
-        // Extension symbols marked with noEmit are managed manually.
-        // TODO(vsm): Change back to `const`.
-        // See https://github.com/dart-lang/sdk/issues/40380.
-        items.add(js.statement('var # = #;', [id, value]));
+      // Emit hoisted extension symbols that are marked as noEmit in regular as
+      // well as incremental mode (if needed) since they are going to be
+      // referenced as such in the generated expression.
+      if (!incrementalMode ||
+          _symbolContainer.incrementalModuleItems.contains(id)) {
+        if (!_symbolContainer.canEmit(id)) {
+          // Extension symbols marked with noEmit are managed manually.
+          // TODO(vsm): Change back to `const`.
+          // See https://github.com/dart-lang/sdk/issues/40380.
+          items.add(js.statement('var # = #;', [id, value]));
+        }
+      }
+      if (_symbolContainer.incrementalModuleItems.contains(id)) {
+        setEmitIfIncremental(
+            libraryToModule(coreLibrary), extensionSymbolsModule.name);
       }
       _symbolContainer[id] = value;
     });
   }
 
+  /// Emits exports as imports into [items].
+  ///
+  /// Use information from exports to re-define library variables referenced
+  /// inside compiled expressions in incremental mode. That matches importing
+  /// a current module into the symbol used to represent the library during
+  /// original compilation in [ProgramCompiler.emitModule].
+  ///
+  /// Example of exports emitted to JavaScript during emitModule:
+  ///
+  /// ```
+  /// dart.trackLibraries("web/main", { ... });
+  /// // Exports:
+  /// return {
+  ///  web__main: main
+  /// };
+  /// ```
+  ///
+  /// The transformation to imports during expression compilation converts the
+  /// exports above to:
+  ///
+  /// ```
+  /// const web__main = require('web/main');
+  /// const main = web__main.web__main;
+  /// ```
+  ///
+  /// Where the compiled expression references `main`.
+  @protected
+  void emitExportsAsImports(List<js_ast.ModuleItem> items, Library current) {
+    var exports = <js_ast.NameSpecifier>[];
+    assert(incrementalMode);
+    assert(!isBuildingSdk);
+
+    var module = libraryToModule(current);
+    var usedLibraries = incrementalModules[module] ?? {};
+
+    if (usedLibraries.isNotEmpty) {
+      _libraries.forEach((library, libraryId) {
+        if (usedLibraries.contains(jsLibraryName(library))) {
+          var alias = jsLibraryAlias(library);
+          var aliasId = alias == null ? libraryId : js_ast.TemporaryId(alias);
+          var asName = alias == null ? null : libraryId;
+          exports.add(js_ast.NameSpecifier(aliasId, asName: asName));
+        }
+      });
+
+      items.add(js_ast.ImportDeclaration(
+          namedImports: exports, from: js.string(module, "'")));
+    }
+  }
+
+  /// Emits imports and extension methods into [items].
+  @protected
+  void emitImportsAndExtensionSymbols(List<js_ast.ModuleItem> items,
+      {bool forceExtensionSymbols = false}) {
+    emitImports(items);
+    emitExtensionSymbols(items, forceExtensionSymbols: forceExtensionSymbols);
+  }
+
   void _emitDebuggerExtensionInfo(String name) {
     var properties = <js_ast.Property>[];
     var parts = <js_ast.Property>[];
@@ -568,27 +711,26 @@
   ///
   /// A symbol lookup on an id marked no emit omits the symbol accessor.
   js_ast.Expression getSymbol(js_ast.Identifier id) {
+    _symbolContainer.setEmitIfIncremental(id);
     return _symbolContainer.canEmit(id) ? _symbolContainer.access(id) : id;
   }
 
   /// Returns the raw JS value associated with [id].
   js_ast.Expression getSymbolValue(js_ast.Identifier id) {
+    _symbolContainer.setEmitIfIncremental(id);
     return _symbolContainer[id];
   }
 
   /// Inserts a symbol into the symbol table.
   js_ast.Expression addSymbol(js_ast.Identifier id, js_ast.Expression symbol) {
     _symbolContainer[id] = symbol;
+    _symbolContainer.setEmitIfIncremental(id);
     if (!containerizeSymbols) {
       _symbolContainer.setNoEmit(id);
     }
     return _symbolContainer[id];
   }
 
-  void setSymbolContainerIncrementalMode(bool setting) {
-    _symbolContainer.incrementalMode = setting;
-  }
-
   /// Finishes the module created by [startModule], by combining the preable
   /// [items] with the [moduleItems] that have been emitted.
   ///
@@ -646,7 +788,9 @@
       _extensionSymbols[name] = id;
       addSymbol(id, id);
     }
-    return _extensionSymbols[name];
+    var symbolId = _extensionSymbols[name];
+    _symbolContainer.setEmitIfIncremental(symbolId);
+    return symbolId;
   }
 
   /// Shorthand for identifier-like property names.
diff --git a/pkg/dev_compiler/lib/src/kernel/compiler.dart b/pkg/dev_compiler/lib/src/kernel/compiler.dart
index faae4a6..a1437e9 100644
--- a/pkg/dev_compiler/lib/src/kernel/compiler.dart
+++ b/pkg/dev_compiler/lib/src/kernel/compiler.dart
@@ -26,7 +26,7 @@
 import '../compiler/shared_command.dart' show SharedCompilerOptions;
 import '../compiler/shared_compiler.dart';
 import '../js_ast/js_ast.dart' as js_ast;
-import '../js_ast/js_ast.dart' show js;
+import '../js_ast/js_ast.dart' show ModuleItem, js;
 import '../js_ast/source_map_printer.dart' show NodeEnd, NodeSpan, HoverComment;
 import 'constants.dart';
 import 'js_interop.dart';
@@ -77,7 +77,7 @@
   final _constLazyAccessors = <js_ast.Method>[];
 
   /// Container for holding the results of lazily-evaluated constants.
-  final _constTableCache = ModuleItemContainer<String>.asArray('C');
+  var _constTableCache = ModuleItemContainer<String>.asArray('C');
 
   /// Tracks the index in [moduleItems] where the const table must be inserted.
   /// Required for SDK builds due to internal circular dependencies.
@@ -221,7 +221,7 @@
   final constAliasCache = HashMap<Constant, js_ast.Expression>();
 
   /// Maps uri strings in asserts and elsewhere to hoisted identifiers.
-  final _uriContainer = ModuleItemContainer<String>.asArray('I');
+  var _uriContainer = ModuleItemContainer<String>.asArray('I');
 
   final Class _jsArrayClass;
   final Class _privateSymbolClass;
@@ -242,6 +242,8 @@
 
   final NullableInference _nullableInference;
 
+  bool _moduleEmitted = false;
+
   factory ProgramCompiler(
       Component component,
       ClassHierarchy hierarchy,
@@ -320,8 +322,10 @@
   InterfaceType get internalSymbolType =>
       _coreTypes.legacyRawType(_coreTypes.internalSymbolClass);
 
+  /// Module can be emitted only once, and the compiler can be reused after
+  /// only in incremental mode, for expression compilation only.
   js_ast.Program emitModule(Component component) {
-    if (moduleItems.isNotEmpty) {
+    if (_moduleEmitted) {
       throw StateError('Can only call emitModule once.');
     }
     _component = component;
@@ -443,7 +447,12 @@
     // Emit the hoisted type table cache variables
     items.addAll(_typeTable.dischargeBoundTypes());
 
-    return finishModule(items, _options.moduleName);
+    var module = finishModule(items, _options.moduleName);
+
+    // Mark as finished for incremental mode, so it is safe to
+    // switch to the incremental mode for expression compilation.
+    _moduleEmitted = true;
+    return module;
   }
 
   @override
@@ -2530,8 +2539,14 @@
     return libraryJSName != null ? '$libraryJSName.$jsName' : jsName;
   }
 
+  String _emitJsNameWithoutGlobal(NamedNode n) {
+    if (!usesJSInterop(n)) return null;
+    setEmitIfIncrementalLibrary(getLibrary(n));
+    return _jsNameWithoutGlobal(n);
+  }
+
   js_ast.PropertyAccess _emitJSInterop(NamedNode n) {
-    var jsName = _jsNameWithoutGlobal(n);
+    var jsName = _emitJsNameWithoutGlobal(n);
     if (jsName == null) return null;
     return _emitJSInteropForGlobal(jsName);
   }
@@ -2762,7 +2777,7 @@
       typeRep = runtimeCall(
           'anonymousJSType(#)', [js.escapedString(getLocalClassName(c))]);
     } else {
-      var jsName = _jsNameWithoutGlobal(c);
+      var jsName = _emitJsNameWithoutGlobal(c);
       if (jsName != null) {
         typeRep = runtimeCall('lazyJSType(() => #, #)',
             [_emitJSInteropForGlobal(jsName), js.escapedString(jsName)]);
@@ -3072,6 +3087,30 @@
   js_ast.Expression visitTypedefType(TypedefType type) =>
       visitFunctionType(type.unalias as FunctionType);
 
+  /// Set incremental mode for expression compilation.
+  ///
+  /// Called for each expression compilation to set the intremental mode
+  /// and clear referenced items.
+  ///
+  /// The compiler cannot revert to non-incremental mode, and requires the
+  /// original module to be already emitted by the same compiler instance.
+  @override
+  void setIncrementalMode() {
+    if (!_moduleEmitted) {
+      throw StateError(
+          'Cannot run in incremental mode before module completion');
+    }
+    super.setIncrementalMode();
+
+    _constTableCache = ModuleItemContainer<String>.asArray('C');
+    _constLazyAccessors.clear();
+    constAliasCache.clear();
+
+    _uriContainer = ModuleItemContainer<String>.asArray('I');
+
+    _typeTable.typeContainer.setIncrementalMode();
+  }
+
   /// Emits function after initial compilation.
   ///
   /// Emits function from kernel [functionNode] with name [name] in the context
@@ -3079,68 +3118,67 @@
   /// finished. For example, this happens in expression compilation during
   /// expression evaluation initiated by the user from the IDE and coordinated
   /// by the debugger.
-  js_ast.Fun emitFunctionIncremental(
-      Library library, Class cls, FunctionNode functionNode, String name) {
-    // setup context
+  /// Triggers incremental mode, which only emits symbols, types, constants,
+  /// libraries, and uris referenced in the expression compilation result.
+  js_ast.Fun emitFunctionIncremental(List<ModuleItem> items, Library library,
+      Class cls, FunctionNode functionNode, String name) {
+    // Setup context.
     _currentLibrary = library;
     _staticTypeContext.enterLibrary(_currentLibrary);
     _currentClass = cls;
 
+    // Keep all symbols in containers.
+    containerizeSymbols = true;
+
+    // Set all tables to incremental mode, so we can only emit elements that
+    // were referenced the compiled code for the expression.
+    setIncrementalMode();
+
     // Do not add formal parameter checks for the top-level synthetic function
     // generated for expression evaluation, as those parameters are a set of
-    // variables from the current scope, and should alredy be checked in the
+    // variables from the current scope, and should already be checked in the
     // original code.
     _checkParameters = false;
 
-    // Set module item containers to incremental mode.
-    setSymbolContainerIncrementalMode(true);
-    _typeTable.typeContainer.incrementalMode = true;
-    _constTableCache.incrementalMode = true;
-
-    // Emit function with additional information, such as types that are used
-    // in the expression.
+    // Emit function while recoding elements accessed from tables.
     var fun = _emitFunction(functionNode, name);
 
-    var types = _typeTable.dischargeBoundTypes();
-    var constants = _dischargeConstTable();
+    var extensionSymbols = <js_ast.Statement>[];
+    emitExtensionSymbols(extensionSymbols);
 
-    var body = js_ast.Block([...?types, ...?constants, ...fun.body.statements]);
+    // Add all elements from tables accessed in the function
+    var body = js_ast.Block([
+      ...extensionSymbols,
+      ..._typeTable.dischargeBoundTypes(),
+      ...symbolContainer.emit(),
+      ..._emitConstTable(),
+      ..._uriContainer.emit(),
+      ...fun.body.statements
+    ]);
+
+    // Import all necessary libraries, including libraries accessed from the
+    // current module and libraries accessed from the type table.
+    for (var library in _typeTable.incrementalLibraries()) {
+      setEmitIfIncrementalLibrary(library);
+    }
+    emitImports(items);
+    emitExportsAsImports(items, _currentLibrary);
+
     return js_ast.Fun(fun.params, body);
   }
 
-  /// Emit all collected const symbols
-  ///
-  /// This is similar to how constants are emitted during
-  /// initial compilation in emitModule
-  ///
-  /// TODO: unify the code with emitModule.
-  List<js_ast.Statement> _dischargeConstTable() {
-    var items = <js_ast.Statement>[];
-
+  List<js_ast.Statement> _emitConstTable() {
+    var constTable = <js_ast.Statement>[];
     if (_constLazyAccessors.isNotEmpty) {
-      var constTableBody = runtimeStatement(
-          'defineLazy(#, { # }, false)', [_constTable, _constLazyAccessors]);
-      items.add(constTableBody);
-      _constLazyAccessors.clear();
-    }
+      constTable
+          .add(js.statement('const # = Object.create(null);', [_constTable]));
 
-    _copyAndFlattenBlocks(items, moduleItems);
-    moduleItems.clear();
-    return items;
-  }
+      constTable.add(runtimeStatement(
+          'defineLazy(#, { # }, false)', [_constTable, _constLazyAccessors]));
 
-  /// Flattens blocks in [items] to a single list.
-  ///
-  /// This will not flatten blocks that are marked as being scopes.
-  void _copyAndFlattenBlocks(
-      List<js_ast.Statement> result, Iterable<js_ast.ModuleItem> items) {
-    for (var item in items) {
-      if (item is js_ast.Block && !item.isScope) {
-        _copyAndFlattenBlocks(result, item.statements);
-      } else {
-        result.add(item as js_ast.Statement);
-      }
+      constTable.addAll(_constTableCache.emit());
     }
+    return constTable;
   }
 
   js_ast.Fun _emitFunction(FunctionNode f, String name) {
@@ -3729,6 +3767,7 @@
     if (!_uriContainer.contains(uri)) {
       _uriContainer[uri] = js_ast.LiteralString('"$uri"');
     }
+    _uriContainer.setEmitIfIncremental(uri);
     return _uriContainer.access(uri);
   }
 
diff --git a/pkg/dev_compiler/lib/src/kernel/expression_compiler.dart b/pkg/dev_compiler/lib/src/kernel/expression_compiler.dart
index a4c69bd..2758926 100644
--- a/pkg/dev_compiler/lib/src/kernel/expression_compiler.dart
+++ b/pkg/dev_compiler/lib/src/kernel/expression_compiler.dart
@@ -13,6 +13,8 @@
     show Code, Message, PlainAndColorizedString;
 
 import 'package:dev_compiler/dev_compiler.dart';
+import 'package:dev_compiler/src/compiler/js_names.dart' as js_ast;
+import 'package:dev_compiler/src/compiler/module_builder.dart';
 import 'package:dev_compiler/src/js_ast/js_ast.dart' as js_ast;
 import 'package:dev_compiler/src/kernel/compiler.dart';
 
@@ -31,8 +33,6 @@
         Member,
         Node,
         Procedure,
-        PropertyGet,
-        PropertySet,
         RedirectingFactoryConstructor,
         TreeNode,
         TypeParameter,
@@ -114,7 +114,7 @@
   }
 
   DartScope build() {
-    if (_offset == null || _library == null || _member == null) return null;
+    if (_offset == null || _library == null) return null;
 
     return DartScope(_library, _cls, _member, _definitions, _typeParameters);
   }
@@ -127,7 +127,10 @@
   @override
   void visitLibrary(Library library) {
     _library = library;
-    _offset = _component.getOffset(_library.fileUri, _line, _column);
+    _offset = 0;
+    if (_line > 0) {
+      _offset = _component.getOffset(_library.fileUri, _line, _column);
+    }
 
     // Exit early if the evaluation offset is not found.
     // Note: the complete scope is not found in this case,
@@ -261,53 +264,6 @@
   }
 }
 
-/// Collect private fields and libraries used in expression.
-///
-/// Used during expression evaluation to find symbols
-/// for private fields. The symbols are used in the ddc
-/// compilation of the expression, are not always avalable
-/// in the JavaScript scope, so we need to redefine them.
-///
-/// See [_addSymbolDefinitions]
-class PrivateFieldsVisitor extends Visitor<void> with VisitorVoidMixin {
-  final Map<String, Library> privateFields = {};
-
-  @override
-  void defaultNode(Node node) {
-    node.visitChildren(this);
-  }
-
-  @override
-  void visitFieldReference(Field node) {
-    if (node.name.isPrivate && !node.isStatic) {
-      privateFields[node.name.text] = node.enclosingLibrary;
-    }
-  }
-
-  @override
-  void visitField(Field node) {
-    if (node.name.isPrivate && !node.isStatic) {
-      privateFields[node.name.text] = node.enclosingLibrary;
-    }
-  }
-
-  @override
-  void visitPropertyGet(PropertyGet node) {
-    var member = node.interfaceTarget;
-    if (node.name.isPrivate && member != null && member.isInstanceMember) {
-      privateFields[node.name.text] = node.interfaceTarget?.enclosingLibrary;
-    }
-  }
-
-  @override
-  void visitPropertySet(PropertySet node) {
-    var member = node.interfaceTarget;
-    if (node.name.isPrivate && member != null && member.isInstanceMember) {
-      privateFields[node.name.text] = node.interfaceTarget?.enclosingLibrary;
-    }
-  }
-}
-
 class ExpressionCompiler {
   static final String debugProcedureName = '\$dartEval';
 
@@ -317,6 +273,7 @@
   final IncrementalCompiler _compiler;
   final ProgramCompiler _kernel2jsCompiler;
   final Component _component;
+  final ModuleFormat _moduleFormat;
 
   DiagnosticMessageHandler onDiagnostic;
 
@@ -328,6 +285,7 @@
 
   ExpressionCompiler(
     this._options,
+    this._moduleFormat,
     this.errors,
     this._compiler,
     this._kernel2jsCompiler,
@@ -494,81 +452,27 @@
 
     // TODO: make this code clear and assumptions enforceable
     // https://github.com/dart-lang/sdk/issues/43273
-    //
-    // We assume here that ExpressionCompiler is always created using
-    // onDisgnostic method that adds to the error list that is passed
-    // to the same invocation of the ExpressionCompiler constructor.
-    // We only use the error list once - below, to detect if the frontend
-    // compilation of the expression has failed.
     if (errors.isNotEmpty) {
       return null;
     }
 
-    var jsFun = _kernel2jsCompiler.emitFunctionIncremental(
+    var imports = <js_ast.ModuleItem>[];
+    var jsFun = _kernel2jsCompiler.emitFunctionIncremental(imports,
         scope.library, scope.cls, procedure.function, '$debugProcedureName');
 
     _log('Generated JavaScript for expression');
 
-    var jsFunModified = _addSymbolDefinitions(procedure, jsFun, scope);
-
-    _log('Added symbol definitions to JavaScript');
-
     // print JS ast to string for evaluation
-
     var context = js_ast.SimpleJavaScriptPrintingContext();
     var opts =
         js_ast.JavaScriptPrintingOptions(allowKeywordsInProperties: true);
 
-    jsFunModified.accept(js_ast.Printer(opts, context));
-    _log('Performed JavaScript adjustments for expression');
+    var tree = transformFunctionModuleFormat(imports, jsFun, _moduleFormat);
+    tree.accept(
+        js_ast.Printer(opts, context, localNamer: js_ast.TemporaryNamer(tree)));
+
+    _log('Added imports and renamed variables for expression');
 
     return context.getText();
   }
-
-  /// Add symbol definitions for all symbols in compiled expression
-  ///
-  /// Example:
-  ///
-  ///   compilation of this._field from library 'main'
-  ///
-  /// Symbol definition:
-  ///
-  ///   let _f = dart.privateName(main, "_f");
-  ///
-  /// Expression generated by ddc:
-  ///
-  ///   this[_f]
-  ///
-  /// TODO: this is a temporary workaround to make JavaScript produced
-  /// by the ProgramCompiler self-contained.
-  /// Issue: https://github.com/dart-lang/sdk/issues/41480
-  js_ast.Fun _addSymbolDefinitions(
-      Procedure procedure, js_ast.Fun jsFun, DartScope scope) {
-    // get private fields accessed by the evaluated expression
-    var fieldsCollector = PrivateFieldsVisitor();
-    procedure.accept(fieldsCollector);
-    var privateFields = fieldsCollector.privateFields;
-
-    // collect library names where private symbols are defined
-    var libraryForField = privateFields.map((field, library) =>
-        MapEntry(field, _kernel2jsCompiler.emitLibraryName(library).name));
-
-    var body = js_ast.Block([
-      // re-create private field accessors
-      ...libraryForField.keys.map(
-          (String field) => _createPrivateField(field, libraryForField[field])),
-      // statements generated by the FE
-      ...jsFun.body.statements
-    ]);
-    return js_ast.Fun(jsFun.params, body);
-  }
-
-  /// Creates a private symbol definition
-  ///
-  /// example:
-  /// let _f = dart.privateName(main, "_f");
-  js_ast.Statement _createPrivateField(String field, String library) {
-    return js_ast.js.statement('let # = dart.privateName(#, #)',
-        [field, library, js_ast.js.string(field)]);
-  }
 }
diff --git a/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart b/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart
index 9956b4f..16a64f3 100644
--- a/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart
+++ b/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart
@@ -10,6 +10,8 @@
 
 import 'package:args/args.dart';
 import 'package:build_integration/file_system/multi_root.dart';
+import 'package:dev_compiler/dev_compiler.dart';
+import 'package:dev_compiler/src/compiler/module_builder.dart';
 import 'package:front_end/src/api_prototype/file_system.dart';
 import 'package:front_end/src/api_unstable/ddc.dart';
 import 'package:kernel/ast.dart' show Component, Library;
@@ -82,11 +84,13 @@
 
   final ProcessedOptions _processedOptions;
   final CompilerOptions _compilerOptions;
+  final ModuleFormat _moduleFormat;
   final Component _sdkComponent;
 
   ExpressionCompilerWorker._(
     this._processedOptions,
     this._compilerOptions,
+    this._moduleFormat,
     this._sdkComponent,
     this.requestStream,
     this.sendResponse,
@@ -120,6 +124,9 @@
         parseExperimentalArguments(
             parsedArgs['enable-experiment'] as List<String>),
         onError: (e) => throw e);
+
+    var moduleFormat = parseModuleFormat(parsedArgs['module-format'] as String);
+
     return create(
       librariesSpecificationUri:
           _argToUri(parsedArgs['libraries-file'] as String),
@@ -131,6 +138,7 @@
       sdkRoot: _argToUri(parsedArgs['sdk-root'] as String),
       trackWidgetCreation: parsedArgs['track-widget-creation'] as bool,
       soundNullSafety: parsedArgs['sound-null-safety'] as bool,
+      moduleFormat: moduleFormat,
       verbose: parsedArgs['verbose'] as bool,
       requestStream: requestStream,
       sendResponse: sendResponse,
@@ -152,6 +160,7 @@
     Uri sdkRoot,
     bool trackWidgetCreation = false,
     bool soundNullSafety = false,
+    ModuleFormat moduleFormat = ModuleFormat.amd,
     bool verbose = false,
     Stream<Map<String, dynamic>> requestStream, // Defaults to read from stdin
     void Function(Map<String, dynamic>)
@@ -185,7 +194,7 @@
     });
 
     return ExpressionCompilerWorker._(processedOptions, compilerOptions,
-        sdkComponent, requestStream, sendResponse)
+        moduleFormat, sdkComponent, requestStream, sendResponse)
       .._updateCache(sdkComponent, dartSdkModule, true);
   }
 
@@ -309,6 +318,7 @@
           sourceMap: true,
           summarizeApi: false,
           moduleName: moduleName,
+          soundNullSafety: _compilerOptions.nnbdMode == NnbdMode.Strong,
           // Disable asserts due to failures to load source and
           // locations on kernel loaded from dill files in DDC.
           // https://github.com/dart-lang/sdk/issues/43986
@@ -342,6 +352,7 @@
 
     var expressionCompiler = ExpressionCompiler(
       _compilerOptions,
+      _moduleFormat,
       errors,
       incrementalCompiler,
       kernel2jsCompiler,
@@ -673,6 +684,7 @@
   ..addOption('sdk-root')
   ..addOption('asset-server-address')
   ..addOption('asset-server-port')
+  ..addOption('module-format')
   ..addFlag('track-widget-creation', defaultsTo: false)
   ..addFlag('sound-null-safety', defaultsTo: false)
   ..addFlag('verbose', defaultsTo: false);
diff --git a/pkg/dev_compiler/lib/src/kernel/type_table.dart b/pkg/dev_compiler/lib/src/kernel/type_table.dart
index 57b23f0..15cbd31 100644
--- a/pkg/dev_compiler/lib/src/kernel/type_table.dart
+++ b/pkg/dev_compiler/lib/src/kernel/type_table.dart
@@ -9,7 +9,8 @@
 import 'package:kernel/kernel.dart';
 
 import '../compiler/js_names.dart' as js_ast;
-import '../compiler/module_containers.dart' show ModuleItemContainer;
+import '../compiler/module_containers.dart'
+    show ModuleItemContainer, ModuleItemData;
 import '../js_ast/js_ast.dart' as js_ast;
 import '../js_ast/js_ast.dart' show js;
 import 'kernel_helpers.dart';
@@ -119,16 +120,26 @@
   bool _isNamed(DartType type) =>
       typeContainer.contains(type) || _unboundTypeIds.containsKey(type);
 
+  Set<Library> incrementalLibraries() {
+    var libraries = <Library>{};
+    for (var t in typeContainer.incrementalModuleItems) {
+      if (t is InterfaceType) {
+        libraries.add(t.classNode.enclosingLibrary);
+      }
+    }
+    return libraries;
+  }
+
   /// Emit the initializer statements for the type container, which contains
   /// all named types with fully bound type parameters.
   List<js_ast.Statement> dischargeBoundTypes() {
-    for (var t in typeContainer.keys) {
-      typeContainer[t] = js.call('() => ((# = #.constFn(#))())',
-          [typeContainer.access(t), _runtimeModule, typeContainer[t]]);
+    js_ast.Expression emitValue(DartType t, ModuleItemData data) {
+      var access = js.call('#.#', [data.id, data.jsKey]);
+      return js.call('() => ((# = #.constFn(#))())',
+          [access, _runtimeModule, data.jsValue]);
     }
-    var boundTypes = typeContainer.incrementalMode
-        ? typeContainer.emitIncremental()
-        : typeContainer.emit();
+
+    var boundTypes = typeContainer.emit(emitValue: emitValue);
     // Bound types should only be emitted once (even across multiple evals).
     for (var t in typeContainer.keys) {
       typeContainer.setNoEmit(t);
@@ -172,6 +183,7 @@
     if (!typeContainer.contains(type)) {
       typeContainer[type] = typeRep;
     }
+    typeContainer.setEmitIfIncremental(type);
     return _unboundTypeIds[type] ?? typeContainer.access(type);
   }
 
diff --git a/pkg/dev_compiler/test/expression_compiler/expression_compiler_test.dart b/pkg/dev_compiler/test/expression_compiler/expression_compiler_test.dart
index b335acd..bfec31c 100644
--- a/pkg/dev_compiler/test/expression_compiler/expression_compiler_test.dart
+++ b/pkg/dev_compiler/test/expression_compiler/expression_compiler_test.dart
@@ -8,7 +8,9 @@
 
 import 'package:cli_util/cli_util.dart';
 import 'package:dev_compiler/dev_compiler.dart';
+import 'package:dev_compiler/src/compiler/js_names.dart';
 import 'package:dev_compiler/src/compiler/module_builder.dart';
+import 'package:dev_compiler/src/js_ast/js_ast.dart';
 import 'package:front_end/src/api_unstable/ddc.dart';
 import 'package:front_end/src/compute_platform_binaries_location.dart';
 import 'package:front_end/src/fasta/incremental_serializer.dart';
@@ -16,6 +18,7 @@
 import 'package:kernel/target/targets.dart';
 import 'package:path/path.dart' as p;
 import 'package:test/test.dart';
+import 'package:vm/transformations/type_flow/utils.dart';
 
 // TODO(annagrin): Replace javascript matching in tests below with evaluating
 // the javascript and checking the result.
@@ -74,8 +77,11 @@
   final List<String> errors = [];
   final CompilerOptions options;
   final String dartLangComment;
+  final ModuleFormat moduleFormat;
+  final bool soundNullSafety;
 
-  SetupCompilerOptions(bool soundNullSafety)
+  SetupCompilerOptions(
+      {this.soundNullSafety = true, this.moduleFormat = ModuleFormat.amd})
       : options = getOptions(soundNullSafety),
         dartLangComment =
             soundNullSafety ? dartSoundComment : dartUnsoundComment {
@@ -145,8 +151,12 @@
     component.computeCanonicalNames();
 
     // initialize ddc
+    var moduleName = 'foo.dart';
     var classHierarchy = compiler.getClassHierarchy();
-    var compilerOptions = SharedCompilerOptions(replCompile: true);
+    var compilerOptions = SharedCompilerOptions(
+        replCompile: true,
+        moduleName: moduleName,
+        soundNullSafety: setup.soundNullSafety);
     var coreTypes = compiler.getCoreTypes();
 
     final importToSummary = Map<Library, Component>.identity();
@@ -154,16 +164,28 @@
     for (var lib in component.libraries) {
       importToSummary[lib] = component;
     }
-    summaryToModule[component] = 'foo.dart';
+    summaryToModule[component] = moduleName;
 
     var kernel2jsCompiler = ProgramCompiler(component, classHierarchy,
         compilerOptions, importToSummary, summaryToModule,
         coreTypes: coreTypes);
-    kernel2jsCompiler.emitModule(component);
+    var moduleTree = kernel2jsCompiler.emitModule(component);
+
+    {
+      var opts = JavaScriptPrintingOptions(
+          allowKeywordsInProperties: true, allowSingleLineIfStatements: true);
+      var printer = SimpleJavaScriptPrintingContext();
+
+      var tree = transformModuleFormat(ModuleFormat.amd, moduleTree);
+      tree.accept(Printer(opts, printer, localNamer: TemporaryNamer(tree)));
+      var printed = printer.getText();
+      debugPrint(printed);
+    }
 
     // create expression compiler
     var evaluator = ExpressionCompiler(
       setup.options,
+      setup.moduleFormat,
       setup.errors,
       compiler,
       kernel2jsCompiler,
@@ -290,7 +312,62 @@
 
 void main() {
   group('Unsound null safety:', () {
-    var options = SetupCompilerOptions(false);
+    var options = SetupCompilerOptions(soundNullSafety: false);
+
+    group('Expression compiler extension symbols tests', () {
+      var source = '''
+        ${options.dartLangComment}
+
+        main() {
+          List<int> list = {};
+          list.add(0);
+          /* evaluation placeholder */
+        }
+        ''';
+
+      TestDriver driver;
+
+      setUp(() {
+        driver = TestDriver(options, source);
+      });
+
+      tearDown(() {
+        driver.delete();
+      });
+
+      test('extension symbol used in original compilation', () async {
+        await driver.check(
+            scope: <String, String>{'list': 'list'},
+            expression: 'list.add(1)',
+            expectedResult: r'''
+            (function(list) {
+              const dart_sdk = require('dart_sdk');
+              const dartx = dart_sdk.dartx;
+              var $add = dartx.add;
+              var S = {$add: dartx.add};
+              return list[$add](1);
+            }(
+              list
+            ))
+            ''');
+      });
+
+      test('extension symbol used only in expression compilation', () async {
+        await driver.check(
+            scope: <String, String>{'list': 'list'},
+            expression: 'list.first',
+            expectedResult: r'''
+            (function(list) {
+              const dart_sdk = require('dart_sdk');
+              const dartx = dart_sdk.dartx;
+              var S = {$first: dartx.first};
+              return list[S.$first];
+            }(
+              list
+            ))
+            ''');
+      });
+    });
 
     group('Expression compiler scope collection tests', () {
       var source = '''
@@ -360,8 +437,10 @@
         await driver.check(
             scope: <String, String>{'inScope': '1', 'innerInScope': '0'},
             expression: 'global',
-            expectedResult: '''
+            expectedResult: r'''
             (function(inScope, innerInScope) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.global;
             }.bind(this)(
               1,
@@ -374,8 +453,10 @@
         await driver.check(
             scope: <String, String>{'inScope': '1', 'innerInScope': '0'},
             expression: 'staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(inScope, innerInScope) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField;
             }.bind(this)(
               1,
@@ -571,10 +652,23 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'y': '2', 'z': '3'},
             expression: 'main',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, y, z) {
-              T\$Eval.VoidTodynamic = () => (T\$Eval.VoidTodynamic = dart.constFn(dart.fnType(dart.dynamic, [])))();
-              return dart.fn(foo.main, T\$Eval.VoidTodynamic());
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var T = {
+                VoidTodynamic: () => (T.VoidTodynamic = dart.constFn(dart.fnType(dart.dynamic, [])))()
+              };
+              const CT = Object.create(null);
+              dart.defineLazy(CT, {
+                get C0() {
+                  return C[0] = dart.fn(foo.main, T.VoidTodynamic());
+                }
+              }, false);
+              var C = [void 0];
+              return C[0] || CT.C0;
             }(
               1,
               2,
@@ -666,6 +760,8 @@
             expression: 'x + 1',
             expectedResult: '''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.notNull(x) + 1;
             }.bind(this)(
               1
@@ -677,8 +773,12 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return dart.notNull(x) + dart.notNull(foo.C.staticField);
             }.bind(this)(
               1
@@ -690,8 +790,12 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return dart.notNull(x) + dart.notNull(foo.C._staticField);
             }.bind(this)(
               1
@@ -705,6 +809,8 @@
             expression: 'x + field',
             expectedResult: '''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.notNull(x) + dart.notNull(this.field);
             }.bind(this)(
               1
@@ -716,10 +822,14 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _field',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              let _field = dart.privateName(foo, "_field");
-              return dart.notNull(x) + dart.notNull(this[_field]);
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return dart.notNull(x) + dart.notNull(this[S._field$1]);
             }.bind(this)(
               1
             ))
@@ -730,8 +840,12 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + global',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return dart.notNull(x) + dart.notNull(foo.global);
             }.bind(this)(
               1
@@ -769,8 +883,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '"1234".parseInt()',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo['NumberParsing|parseInt']("1234");
             }.bind(this)(
               1
@@ -782,10 +898,14 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_field = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              let _field = dart.privateName(foo, "_field");
-              return this[_field] = 2;
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return this[S._field$1] = 2;
             }.bind(this)(
               1
             ))
@@ -809,8 +929,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C._staticField = 2;
             }.bind(this)(
               1
@@ -822,8 +944,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField = 2;
             }.bind(this)(
               1
@@ -885,8 +1009,12 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return dart.notNull(x) + dart.notNull(foo.C.staticField);
             }.bind(this)(
               1
@@ -898,8 +1026,12 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return dart.notNull(x) + dart.notNull(foo.C._staticField);
             }.bind(this)(
               1
@@ -913,6 +1045,8 @@
             expression: 'x + field',
             expectedResult: '''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.notNull(x) + dart.notNull(this.field);
             }.bind(this)(
               1
@@ -924,10 +1058,14 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _field',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              let _field = dart.privateName(foo, "_field");
-              return dart.notNull(x) + dart.notNull(this[_field]);
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return dart.notNull(x) + dart.notNull(this[S._field$1]);
             }.bind(this)(
             1
             ))
@@ -938,10 +1076,14 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_field = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              let _field = dart.privateName(foo, "_field");
-              return this[_field] = 2;
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return this[S._field$1] = 2;
             }.bind(this)(
             1
             ))
@@ -965,8 +1107,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C._staticField = 2;
             }.bind(this)(
             1
@@ -978,8 +1122,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField = 2;
             }.bind(this)(
             1
@@ -1137,8 +1283,10 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'C(1,3)',
-            expectedResult: '''
+            expectedResult: r'''
               (function(x, c) {
+                const foo$46dart = require('foo.dart');
+                const foo = foo$46dart.foo;
                 return new foo.C.new(1, 3);
               }(
                 1,
@@ -1151,10 +1299,14 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'C(1,3)._field',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
-              let _field = dart.privateName(foo, "_field");
-              return new foo.C.new(1, 3)[_field];
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return new foo.C.new(1, 3)[S._field$1];
             }(
               1,
               null
@@ -1166,8 +1318,10 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'C.staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField;
             }(
               1,
@@ -1201,13 +1355,17 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'c._field',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
-              let _field = dart.privateName(foo, "_field");
-              return c[_field];
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return c[S._field$1];
             }(
-                1,
-                null
+              1,
+              null
             ))
             ''');
       });
@@ -1244,8 +1402,10 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: '"1234".parseInt()',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo['NumberParsing|parseInt']("1234");
             }(
               1,
@@ -1258,10 +1418,14 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'c._field = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
-              let _field = dart.privateName(foo, "_field");
-              return c[_field] = 2;
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return c[S._field$1] = 2;
             }(
               1,
               null
@@ -1294,8 +1458,10 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'C.staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField = 2;
             }(
               1,
@@ -1310,6 +1476,8 @@
             expression: 'print(x)',
             expectedResult: '''
             (function(x, c) {
+              const dart_sdk = require('dart_sdk');
+              const core = dart_sdk.core;
               return core.print(x);
             }(
               1,
@@ -1363,6 +1531,8 @@
             expression: r"'$x+$y+$z'",
             expectedResult: '''
             (function(x, c, y, z) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.str(x) + "+" + dart.str(y) + "+" + dart.str(z);
             }(
               1,
@@ -1379,6 +1549,8 @@
             expression: r"'$y+$z'",
             expectedResult: '''
             (function(x, c, y, z) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.str(y) + "+" + dart.str(z);
             }(
               1,
@@ -1438,12 +1610,14 @@
         driver.delete();
       });
 
-      test('call function using type', () async {
+      test('call function not using type', () async {
         await driver.check(
             scope: <String, String>{'p': '1'},
             expression: 'bar(p)',
-            expectedResult: '''
+            expectedResult: r'''
             (function(p) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.bar(p);
             }(
               1
@@ -1455,12 +1629,19 @@
         await driver.check(
             scope: <String, String>{'p': '0'},
             expression: 'baz(p as String)',
-            expectedResult: '''
+            expectedResult: r'''
             (function(p) {
-              T\$Eval.StringL = () => (T\$Eval.StringL = dart.constFn(dart.legacy(core.String)))();
-              return foo.baz(T\$Eval.StringL().as(p));
+              const dart_sdk = require('dart_sdk');
+              const core = dart_sdk.core;
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var T = {
+                StringL: () => (T.StringL = dart.constFn(dart.legacy(core.String)))()
+              };
+              return foo.baz(T.StringL().as(p));
             }(
-            0
+              0
             ))
             ''');
       });
@@ -1469,12 +1650,24 @@
         await driver.check(
             scope: <String, String>{'p': '1'},
             expression: 'const MyClass(1)',
-            expectedResult: '''
+            expectedResult: r'''
             (function(p) {
-              return dart.const({
-                __proto__: foo.MyClass.prototype,
-                [_t]: 1
-              });
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {MyClass__t: dart.privateName(foo, "MyClass._t")};
+              const CT = Object.create(null);
+              dart.defineLazy(CT, {
+                get C0() {
+                  return C[0] = dart.const({
+                    __proto__: foo.MyClass.prototype,
+                    [S.MyClass__t]: 1
+                  });
+                }
+              }, false);
+              var C = [void 0];
+              return C[0] || CT.C0;
             }(
               1
             ))
@@ -1499,8 +1692,10 @@
         await driver.check(
             scope: <String, String>{'p': '1'},
             expression: "Key('t')",
-            expectedResult: '''
+            expectedResult: r'''
             (function(p) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return new foo.ValueKey.new("t");
             }(
               1
@@ -1512,12 +1707,24 @@
         await driver.check(
             scope: <String, String>{'p': '1'},
             expression: "const Key('t')",
-            expectedResult: '''
+            expectedResult: r'''
             (function(p) {
-              return dart.const({
-                __proto__: foo.ValueKey.prototype,
-                [value]: "t"
-                });
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {ValueKey_value: dart.privateName(foo, "ValueKey.value")};
+              const CT = Object.create(null);
+              dart.defineLazy(CT, {
+                get C0() {
+                  return C[0] = dart.const({
+                    __proto__: foo.ValueKey.prototype,
+                    [S.ValueKey_value]: "t"
+                  });
+                }
+              }, false);
+              var C = [void 0];
+              return C[0] || CT.C0;
             }(
               1
             ))
@@ -1610,6 +1817,8 @@
             expression: 'x + 1',
             expectedResult: '''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.notNull(x) + 1;
             }.bind(this)(
               1
@@ -1621,8 +1830,12 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return dart.notNull(x) + dart.notNull(foo.C.staticField);
             }.bind(this)(
               1
@@ -1634,8 +1847,12 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return dart.notNull(x) + dart.notNull(foo.C._staticField);
             }.bind(this)(
               1
@@ -1649,6 +1866,8 @@
             expression: 'x + field',
             expectedResult: '''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.notNull(x) + dart.notNull(this.field);
             }.bind(this)(
               1
@@ -1660,10 +1879,14 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _field',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              let _field = dart.privateName(foo, "_field");
-              return dart.notNull(x) + dart.notNull(this[_field]);
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return dart.notNull(x) + dart.notNull(this[S._field$1]);
             }.bind(this)(
                 1
             ))
@@ -1674,8 +1897,12 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + global',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return dart.notNull(x) + dart.notNull(foo.global);
             }.bind(this)(
               1
@@ -1713,27 +1940,33 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '"1234".parseInt()',
-            expectedResult: '''
-          (function(x) {
-            return foo['NumberParsing|parseInt']("1234");
-          }.bind(this)(
-            1
-          ))
-          ''');
+            expectedResult: r'''
+            (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return foo['NumberParsing|parseInt']("1234");
+            }.bind(this)(
+              1
+            ))
+            ''');
       });
 
       test('private field modification', () async {
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_field = 2',
-            expectedResult: '''
-          (function(x) {
-            let _field = dart.privateName(foo, "_field");
-            return this[_field] = 2;
-          }.bind(this)(
-            1
-          ))
-          ''');
+            expectedResult: r'''
+            (function(x) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return this[S._field$1] = 2;
+            }.bind(this)(
+              1
+            ))
+            ''');
       });
 
       test('field modification', () async {
@@ -1753,8 +1986,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C._staticField = 2;
             }.bind(this)(
               1
@@ -1766,8 +2001,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField = 2;
             }.bind(this)(
               1
@@ -2047,7 +2284,7 @@
           /* evaluation placeholder */
           return;
         }
-        
+
         void main() => foo();
         ''';
 
@@ -2065,10 +2302,15 @@
         await driver.check(
             scope: <String, String>{'a': 'null', 'check': 'null'},
             expression: 'a is String',
-            expectedResult: '''
+            expectedResult: r'''
             (function(a, check) {
-              T\$Eval.StringL = () => (T\$Eval.StringL = dart.constFn(dart.legacy(core.String)))();
-              return T\$Eval.StringL().is(a);
+              const dart_sdk = require('dart_sdk');
+              const core = dart_sdk.core;
+              const dart = dart_sdk.dart;
+              var T = {
+                StringL: () => (T.StringL = dart.constFn(dart.legacy(core.String)))()
+              };
+              return T.StringL().is(a);
             }(
               null,
               null
@@ -2080,9 +2322,15 @@
         await driver.check(
             scope: <String, String>{'a': 'null', 'check': 'null'},
             expression: 'a is int',
-            expectedResult: '''
+            expectedResult: r'''
             (function(a, check) {
-              return T\$Eval.intL().is(a);
+              const dart_sdk = require('dart_sdk');
+              const core = dart_sdk.core;
+              const dart = dart_sdk.dart;
+              var T = {
+                intL: () => (T.intL = dart.constFn(dart.legacy(core.int)))()
+              };
+              return T.intL().is(a);
             }(
               null,
               null
@@ -2096,11 +2344,22 @@
         await driver.check(
             scope: <String, String>{'a': 'null', 'check': 'null'},
             expression: 'const B()',
-            expectedResult: '''
+            expectedResult: r'''
             (function(a, check) {
-              return dart.const({
-                __proto__: foo.B.prototype
-              });
+             const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              const CT = Object.create(null);
+              dart.defineLazy(CT, {
+                get C0() {
+                  return C[0] = dart.const({
+                    __proto__: foo.B.prototype
+                  });
+                }
+              }, false);
+              var C = [void 0];
+              return C[0] || CT.C0;
             }(
               null,
               null
@@ -2114,11 +2373,22 @@
         await driver.check(
             scope: <String, String>{'a': 'null', 'check': 'null'},
             expression: 'a == const A()',
-            expectedResult: '''
+            expectedResult: r'''
             (function(a, check) {
-              return dart.equals(a, dart.const({
-                __proto__: foo.A.prototype
-              }));
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              const CT = Object.create(null);
+              dart.defineLazy(CT, {
+                get C0() {
+                  return C[0] = dart.const({
+                    __proto__: foo.A.prototype
+                  });
+                }
+              }, false);
+              var C = [void 0];
+              return dart.equals(a, C[0] || CT.C0);
             }(
               null,
               null
@@ -2182,6 +2452,8 @@
             expression: 'TType',
             expectedResult: '''
             (function(TType, KType, a, b) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.wrapType(dart.legacy(TType));
             }.bind(this)(
               TType,
@@ -2192,10 +2464,112 @@
             ''');
       });
     });
+
+    group('Expression compiler tests using extension symbols', () {
+      var source = '''
+        ${options.dartLangComment}
+        void bar() {
+          /* evaluation placeholder */
+        }
+
+        void main() => bar();
+        ''';
+
+      TestDriver driver;
+      setUp(() {
+        driver = TestDriver(options, source);
+      });
+
+      tearDown(() {
+        driver.delete();
+      });
+
+      test('map access', () async {
+        await driver.check(
+            scope: <String, String>{'inScope': '1', 'innerInScope': '0'},
+            expression:
+                '(Map<String, String> params) { return params["index"]; }({})',
+            expectedResult: r'''
+            (function() {
+              const dart_sdk = require('dart_sdk');
+              const core = dart_sdk.core;
+              const _js_helper = dart_sdk._js_helper;
+              const dart = dart_sdk.dart;
+              const dartx = dart_sdk.dartx;
+              var T = {
+                StringL: () => (T.StringL = dart.constFn(dart.legacy(core.String)))(),
+                MapOfStringL$StringL: () => (T.MapOfStringL$StringL = dart.constFn(core.Map$(T.StringL(), T.StringL())))(),
+                MapLOfStringL$StringL: () => (T.MapLOfStringL$StringL = dart.constFn(dart.legacy(T.MapOfStringL$StringL())))(),
+                MapLOfStringL$StringLToStringL: () => (T.MapLOfStringL$StringLToStringL = dart.constFn(dart.fnType(T.StringL(), [T.MapLOfStringL$StringL()])))(),
+                IdentityMapOfStringL$StringL: () => (T.IdentityMapOfStringL$StringL = dart.constFn(_js_helper.IdentityMap$(T.StringL(), T.StringL())))()
+              };
+              var S = {$_get: dartx._get};
+              return dart.fn(params => params[S.$_get]("index"), T.MapLOfStringL$StringLToStringL())(new (T.IdentityMapOfStringL$StringL()).new());
+            }(
+              
+            ))
+            ''');
+      });
+    });
   });
 
   group('Sound null safety:', () {
-    var options = SetupCompilerOptions(true);
+    var options = SetupCompilerOptions(soundNullSafety: true);
+
+    group('Expression compiler extension symbols tests', () {
+      var source = '''
+        ${options.dartLangComment}
+  
+        main() {
+          List<int> list = {};
+          list.add(0);
+          /* evaluation placeholder */
+        }
+        ''';
+
+      TestDriver driver;
+
+      setUp(() {
+        driver = TestDriver(options, source);
+      });
+
+      tearDown(() {
+        driver.delete();
+      });
+
+      test('extension symbol used in original compilation', () async {
+        await driver.check(
+            scope: <String, String>{'list': 'list'},
+            expression: 'list.add(1)',
+            expectedResult: r'''
+            (function(list) {
+              const dart_sdk = require('dart_sdk');
+              const dartx = dart_sdk.dartx;
+              var $add = dartx.add;
+              var S = {$add: dartx.add};
+              return list[$add](1);
+            }(
+              list
+            ))
+            ''');
+      });
+
+      test('extension symbol used only in expression compilation', () async {
+        await driver.check(
+            scope: <String, String>{'list': 'list'},
+            expression: 'list.first',
+            expectedResult: r'''
+            (function(list) {
+              const dart_sdk = require('dart_sdk');
+              const dartx = dart_sdk.dartx;
+              var S = {$first: dartx.first};
+              return list[S.$first];
+            }(
+              list
+            ))
+            ''');
+      });
+    });
 
     group('Expression compiler scope collection tests', () {
       var source = '''
@@ -2265,8 +2639,10 @@
         await driver.check(
             scope: <String, String>{'inScope': '1', 'innerInScope': '0'},
             expression: 'global',
-            expectedResult: '''
+            expectedResult: r'''
             (function(inScope, innerInScope) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.global;
             }.bind(this)(
               1,
@@ -2279,8 +2655,10 @@
         await driver.check(
             scope: <String, String>{'inScope': '1', 'innerInScope': '0'},
             expression: 'staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(inScope, innerInScope) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField;
             }.bind(this)(
               1,
@@ -2476,10 +2854,23 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'y': '2', 'z': '3'},
             expression: 'main',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, y, z) {
-              T\$Eval.VoidTodynamic = () => (T\$Eval.VoidTodynamic = dart.constFn(dart.fnType(dart.dynamic, [])))();
-              return dart.fn(foo.main, T\$Eval.VoidTodynamic());
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var T = {
+                VoidTodynamic: () => (T.VoidTodynamic = dart.constFn(dart.fnType(dart.dynamic, [])))()
+              };
+              const CT = Object.create(null);
+              dart.defineLazy(CT, {
+                get C0() {
+                  return C[0] = dart.fn(foo.main, T.VoidTodynamic());
+                }
+              }, false);
+              var C = [void 0];
+              return C[0] || CT.C0;
             }(
               1,
               2,
@@ -2571,7 +2962,7 @@
             expression: 'x + 1',
             expectedResult: '''
             (function(x) {
-              return dart.notNull(x) + 1;
+              return x + 1;
             }.bind(this)(
               1
             ))
@@ -2582,9 +2973,11 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(foo.C.staticField);
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return x + foo.C.staticField;
             }.bind(this)(
               1
             ))
@@ -2595,9 +2988,11 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(foo.C._staticField);
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return x + foo.C._staticField;
             }.bind(this)(
               1
             ))
@@ -2610,7 +3005,7 @@
             expression: 'x + field',
             expectedResult: '''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(this.field);
+              return x + this.field;
             }.bind(this)(
               1
             ))
@@ -2621,10 +3016,14 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _field',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              let _field = dart.privateName(foo, "_field");
-              return dart.notNull(x) + dart.notNull(this[_field]);
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return x + this[S._field$1];
             }.bind(this)(
               1
             ))
@@ -2635,9 +3034,11 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + global',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(foo.global);
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return x + foo.global;
             }.bind(this)(
               1
             ))
@@ -2674,8 +3075,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '"1234".parseInt()',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo['NumberParsing|parseInt']("1234");
             }.bind(this)(
               1
@@ -2687,10 +3090,14 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_field = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              let _field = dart.privateName(foo, "_field");
-              return this[_field] = 2;
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return this[S._field$1] = 2;
             }.bind(this)(
               1
             ))
@@ -2714,8 +3121,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C._staticField = 2;
             }.bind(this)(
               1
@@ -2727,8 +3136,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField = 2;
             }.bind(this)(
               1
@@ -2790,9 +3201,11 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(foo.C.staticField);
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return x + foo.C.staticField;
             }.bind(this)(
               1
             ))
@@ -2803,9 +3216,11 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(foo.C._staticField);
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return x + foo.C._staticField;
             }.bind(this)(
               1
             ))
@@ -2818,7 +3233,7 @@
             expression: 'x + field',
             expectedResult: '''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(this.field);
+              return x + this.field;
             }.bind(this)(
               1
             ))
@@ -2829,10 +3244,14 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _field',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              let _field = dart.privateName(foo, "_field");
-              return dart.notNull(x) + dart.notNull(this[_field]);
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return x + this[S._field$1];
             }.bind(this)(
             1
             ))
@@ -2843,10 +3262,14 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_field = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              let _field = dart.privateName(foo, "_field");
-              return this[_field] = 2;
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return this[S._field$1] = 2;
             }.bind(this)(
             1
             ))
@@ -2870,8 +3293,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C._staticField = 2;
             }.bind(this)(
             1
@@ -2883,8 +3308,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField = 2;
             }.bind(this)(
             1
@@ -3042,24 +3469,30 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'C(1,3)',
-            expectedResult: '''
-              (function(x, c) {
-                return new foo.C.new(1, 3);
-              }(
-                1,
-                null
-              ))
-              ''');
+            expectedResult: r'''
+            (function(x, c) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return new foo.C.new(1, 3);
+            }(
+              1,
+              null
+            ))
+            ''');
       });
 
       test('access field of new object', () async {
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'C(1,3)._field',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
-              let _field = dart.privateName(foo, "_field");
-              return new foo.C.new(1, 3)[_field];
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return new foo.C.new(1, 3)[S._field$1];
             }(
               1,
               null
@@ -3071,8 +3504,10 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'C.staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField;
             }(
               1,
@@ -3106,10 +3541,14 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'c._field',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
-              let _field = dart.privateName(foo, "_field");
-              return c[_field];
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return c[S._field$1];
             }(
                 1,
                 null
@@ -3149,8 +3588,10 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: '"1234".parseInt()',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo['NumberParsing|parseInt']("1234");
             }(
               1,
@@ -3163,10 +3604,14 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'c._field = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
-              let _field = dart.privateName(foo, "_field");
-              return c[_field] = 2;
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return c[S._field$1] = 2;
             }(
               1,
               null
@@ -3199,8 +3644,10 @@
         await driver.check(
             scope: <String, String>{'x': '1', 'c': 'null'},
             expression: 'C.staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x, c) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField = 2;
             }(
               1,
@@ -3215,6 +3662,8 @@
             expression: 'print(x)',
             expectedResult: '''
             (function(x, c) {
+              const dart_sdk = require('dart_sdk');
+              const core = dart_sdk.core;
               return core.print(x);
             }(
               1,
@@ -3268,6 +3717,8 @@
             expression: r"'$x+$y+$z'",
             expectedResult: '''
             (function(x, c, y, z) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.str(x) + "+" + dart.str(y) + "+" + dart.str(z);
             }(
               1,
@@ -3284,6 +3735,8 @@
             expression: r"'$y+$z'",
             expectedResult: '''
             (function(x, c, y, z) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.str(y) + "+" + dart.str(z);
             }(
               1,
@@ -3347,8 +3800,10 @@
         await driver.check(
             scope: <String, String>{'p': '1'},
             expression: 'bar(p)',
-            expectedResult: '''
+            expectedResult: r'''
             (function(p) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.bar(p);
             }(
               1
@@ -3360,8 +3815,12 @@
         await driver.check(
             scope: <String, String>{'p': '0'},
             expression: 'baz(p as String)',
-            expectedResult: '''
+            expectedResult: r'''
             (function(p) {
+              const dart_sdk = require('dart_sdk');
+              const core = dart_sdk.core;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.baz(core.String.as(p));
             }(
               0
@@ -3373,12 +3832,24 @@
         await driver.check(
             scope: <String, String>{'p': '1'},
             expression: 'const MyClass(1)',
-            expectedResult: '''
+            expectedResult: r'''
             (function(p) {
-              return dart.const({
-                __proto__: foo.MyClass.prototype,
-                [_t]: 1
-              });
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {MyClass__t: dart.privateName(foo, "MyClass._t")};
+              const CT = Object.create(null);
+              dart.defineLazy(CT, {
+                get C0() {
+                  return C[0] = dart.const({
+                    __proto__: foo.MyClass.prototype,
+                    [S.MyClass__t]: 1
+                  });
+                }
+              }, false);
+              var C = [void 0];
+              return C[0] || CT.C0;
             }(
               1
             ))
@@ -3403,8 +3874,10 @@
         await driver.check(
             scope: <String, String>{'p': '1'},
             expression: "Key('t')",
-            expectedResult: '''
+            expectedResult: r'''
             (function(p) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return new foo.ValueKey.new("t");
             }(
               1
@@ -3416,12 +3889,24 @@
         await driver.check(
             scope: <String, String>{'p': '1'},
             expression: "const Key('t')",
-            expectedResult: '''
+            expectedResult: r'''
             (function(p) {
-              return dart.const({
-                __proto__: foo.ValueKey.prototype,
-                [value]: "t"
-                });
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {ValueKey_value: dart.privateName(foo, "ValueKey.value")};
+              const CT = Object.create(null);
+              dart.defineLazy(CT, {
+                get C0() {
+                  return C[0] = dart.const({
+                    __proto__: foo.ValueKey.prototype,
+                    [S.ValueKey_value]: "t"
+                  });
+                }
+              }, false);
+              var C = [void 0];
+              return C[0] || CT.C0;
             }(
               1
             ))
@@ -3514,7 +3999,7 @@
             expression: 'x + 1',
             expectedResult: '''
             (function(x) {
-              return dart.notNull(x) + 1;
+              return x + 1;
             }.bind(this)(
               1
             ))
@@ -3525,9 +4010,11 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(foo.C.staticField);
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return x + foo.C.staticField;
             }.bind(this)(
               1
             ))
@@ -3538,9 +4025,11 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _staticField',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(foo.C._staticField);
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return x + foo.C._staticField;
             }.bind(this)(
               1
             ))
@@ -3553,7 +4042,7 @@
             expression: 'x + field',
             expectedResult: '''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(this.field);
+              return x + this.field;
             }.bind(this)(
               1
             ))
@@ -3564,10 +4053,14 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + _field',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              let _field = dart.privateName(foo, "_field");
-              return dart.notNull(x) + dart.notNull(this[_field]);
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              var S = {_field$1: dart.privateName(foo, "_field")};
+              return x + this[S._field$1];
             }.bind(this)(
                 1
             ))
@@ -3578,9 +4071,11 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'x + global',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
-              return dart.notNull(x) + dart.notNull(foo.global);
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return x + foo.global;
             }.bind(this)(
               1
             ))
@@ -3617,23 +4112,29 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '"1234".parseInt()',
-            expectedResult: '''
-          (function(x) {
-            return foo['NumberParsing|parseInt']("1234");
-          }.bind(this)(
-            1
-          ))
-          ''');
+            expectedResult: r'''
+            (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
+              return foo['NumberParsing|parseInt']("1234");
+            }.bind(this)(
+              1
+            ))
+            ''');
       });
 
       test('private field modification', () async {
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_field = 2',
-            expectedResult: '''
+            expectedResult: r'''
           (function(x) {
-            let _field = dart.privateName(foo, "_field");
-            return this[_field] = 2;
+            const dart_sdk = require('dart_sdk');
+            const dart = dart_sdk.dart;
+            const foo$46dart = require('foo.dart');
+            const foo = foo$46dart.foo;
+            var S = {_field$1: dart.privateName(foo, "_field")};
+            return this[S._field$1] = 2;
           }.bind(this)(
             1
           ))
@@ -3657,8 +4158,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: '_staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C._staticField = 2;
             }.bind(this)(
               1
@@ -3670,8 +4173,10 @@
         await driver.check(
             scope: <String, String>{'x': '1'},
             expression: 'staticField = 2',
-            expectedResult: '''
+            expectedResult: r'''
             (function(x) {
+              const foo$46dart = require('foo.dart');
+              const foo = foo$46dart.foo;
               return foo.C.staticField = 2;
             }.bind(this)(
               1
@@ -3990,6 +4495,8 @@
             expression: 'TType',
             expectedResult: '''
             (function(TType, KType, a, b) {
+              const dart_sdk = require('dart_sdk');
+              const dart = dart_sdk.dart;
               return dart.wrapType(TType);
             }.bind(this)(
               TType,
@@ -4000,5 +4507,51 @@
             ''');
       });
     });
+
+    group('Expression compiler tests using extension symbols', () {
+      var source = '''
+        ${options.dartLangComment}
+        void bar() {
+          /* evaluation placeholder */ 
+        }
+
+        void main() => bar();
+        ''';
+
+      TestDriver driver;
+      setUp(() {
+        driver = TestDriver(options, source);
+      });
+
+      tearDown(() {
+        driver.delete();
+      });
+
+      test('map access', () async {
+        await driver.check(
+            scope: <String, String>{'inScope': '1', 'innerInScope': '0'},
+            expression:
+                '(Map<String, String> params) { return params["index"]; }({})',
+            expectedResult: r'''
+            (function() {
+              const dart_sdk = require('dart_sdk');
+              const core = dart_sdk.core;
+              const _js_helper = dart_sdk._js_helper;
+              const dart = dart_sdk.dart;
+              const dartx = dart_sdk.dartx;
+              var T = {
+                StringN: () => (T.StringN = dart.constFn(dart.nullable(core.String)))(),
+                MapOfString$String: () => (T.MapOfString$String = dart.constFn(core.Map$(core.String, core.String)))(),
+                MapOfString$StringToStringN: () => (T.MapOfString$StringToStringN = dart.constFn(dart.fnType(T.StringN(), [T.MapOfString$String()])))(),
+                IdentityMapOfString$String: () => (T.IdentityMapOfString$String = dart.constFn(_js_helper.IdentityMap$(core.String, core.String)))()
+              };
+              var S = {$_get: dartx._get};
+              return dart.fn(params => params[S.$_get]("index"), T.MapOfString$StringToStringN())(new (T.IdentityMapOfString$String()).new());
+            }(
+              
+            ))
+            ''');
+      });
+    });
   });
 }
diff --git a/pkg/frontend_server/lib/frontend_server.dart b/pkg/frontend_server/lib/frontend_server.dart
index a4208db..139e557 100644
--- a/pkg/frontend_server/lib/frontend_server.dart
+++ b/pkg/frontend_server/lib/frontend_server.dart
@@ -10,7 +10,7 @@
 
 import 'package:args/args.dart';
 import 'package:dev_compiler/dev_compiler.dart'
-    show DevCompilerTarget, ExpressionCompiler;
+    show DevCompilerTarget, ExpressionCompiler, parseModuleFormat;
 
 // front_end/src imports below that require lint `ignore_for_file`
 // are a temporary state of things until frontend team builds better api
@@ -605,6 +605,7 @@
       String filename, String fileSystemScheme, String moduleFormat) async {
     var packageConfig = await loadPackageConfigUri(
         _compilerOptions.packagesFileUri ?? File('.packages').absolute.uri);
+    var soundNullSafety = _compilerOptions.nnbdMode == NnbdMode.Strong;
     final Component component = results.component;
     // Compute strongly connected components.
     final strongComponents = StrongComponents(component,
@@ -623,7 +624,8 @@
         component, strongComponents, fileSystemScheme, packageConfig,
         useDebuggerModuleNames: useDebuggerModuleNames,
         emitDebugMetadata: emitDebugMetadata,
-        moduleFormat: moduleFormat);
+        moduleFormat: moduleFormat,
+        soundNullSafety: soundNullSafety);
     final sourceFileSink = sourceFile.openWrite();
     final manifestFileSink = manifestFile.openWrite();
     final sourceMapsFileSink = sourceMapsFile.openWrite();
@@ -839,6 +841,7 @@
 
     var expressionCompiler = new ExpressionCompiler(
       _compilerOptions,
+      parseModuleFormat(_options['dartdevc-module-format'] as String),
       errors,
       _generator.generator,
       kernel2jsCompiler,
diff --git a/pkg/frontend_server/lib/src/javascript_bundle.dart b/pkg/frontend_server/lib/src/javascript_bundle.dart
index 924c551..346b4d8 100644
--- a/pkg/frontend_server/lib/src/javascript_bundle.dart
+++ b/pkg/frontend_server/lib/src/javascript_bundle.dart
@@ -27,6 +27,7 @@
       this._fileSystemScheme, this._packageConfig,
       {this.useDebuggerModuleNames = false,
       this.emitDebugMetadata = false,
+      this.soundNullSafety = false,
       String moduleFormat})
       : compilers = <String, ProgramCompiler>{},
         _moduleFormat = parseModuleFormat(moduleFormat ?? 'amd') {
@@ -65,6 +66,7 @@
   final bool emitDebugMetadata;
   final Map<String, ProgramCompiler> compilers;
   final ModuleFormat _moduleFormat;
+  final bool soundNullSafety;
 
   List<Component> _summaries;
   List<Uri> _summaryUris;
@@ -135,6 +137,7 @@
           summarizeApi: false,
           emitDebugMetadata: emitDebugMetadata,
           moduleName: moduleName,
+          soundNullSafety: soundNullSafety,
         ),
         importToSummary,
         summaryToModule,
diff --git a/runtime/vm/heap/scavenger.cc b/runtime/vm/heap/scavenger.cc
index e4807d5..5f89dfd 100644
--- a/runtime/vm/heap/scavenger.cc
+++ b/runtime/vm/heap/scavenger.cc
@@ -124,12 +124,28 @@
   virtual void VisitTypedDataViewPointers(TypedDataViewPtr view,
                                           ObjectPtr* first,
                                           ObjectPtr* last) {
-    // First we forward all fields of the typed data view.
+    // TypedDataViews require extra processing to update their
+    // PointerBase::data_ pointer. If the underlying typed data is external, no
+    // update is needed. If the underlying typed data is internal, the pointer
+    // must be updated if the typed data was copied or promoted. We cannot
+    // safely dereference the underlying typed data to make this distinction.
+    // It may have been forwarded by a different scavanger worker, so the access
+    // could have a data race. Rather than checking the CID of the underlying
+    // typed data, which requires dereferencing the copied/promoted header, we
+    // compare the view's internal pointer to what it should be if the
+    // underlying typed data was internal, and assume that external typed data
+    // never points into the Dart heap. We must do this before VisitPointers
+    // because we want to compare the old pointer and old typed data.
+    const bool is_external =
+        view->untag()->data_ != view->untag()->DataFieldForInternalTypedData();
+
+    // Forward all fields of the typed data view.
     VisitPointers(first, last);
 
     if (view->untag()->data_ == nullptr) {
       ASSERT(RawSmiValue(view->untag()->offset_in_bytes_) == 0 &&
              RawSmiValue(view->untag()->length_) == 0);
+      ASSERT(is_external);
       return;
     }
 
@@ -146,17 +162,21 @@
         *reinterpret_cast<uword*>(UntaggedObject::ToAddr(td));
     ASSERT(!IsForwarding(td_header) || td->IsOldObject());
 
-    // We can always obtain the class id from the forwarded backing store.
-    const classid_t cid = td->GetClassId();
+    if (!parallel) {
+      // When there is only one worker, there is no data race.
+      ASSERT_EQUAL(IsExternalTypedDataClassId(td->GetClassId()), is_external);
+    }
 
     // If we have external typed data we can simply return since the backing
     // store lives in C-heap and will not move.
-    if (IsExternalTypedDataClassId(cid)) {
+    if (is_external) {
       return;
     }
 
     // Now we update the inner pointer.
-    ASSERT(IsTypedDataClassId(cid));
+    if (!parallel) {
+      ASSERT(IsTypedDataClassId(td->GetClassId()));
+    }
     view->untag()->RecomputeDataFieldForInternalTypedData();
   }
 
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 4d42361..af6332c 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -16513,7 +16513,7 @@
     for (intptr_t i = 0; i < length_; i++) {
       comments_[i].pc_offset = comments.PCOffsetAt(i);
       comments_[i].comment =
-          Utils::CreateCStringUniquePtr(strdup(comments.CommentAt(i)));
+          Utils::CreateCStringUniquePtr(Utils::StrDup(comments.CommentAt(i)));
     }
   }
 
diff --git a/runtime/vm/raw_object.h b/runtime/vm/raw_object.h
index 56a71b7..82c1998 100644
--- a/runtime/vm/raw_object.h
+++ b/runtime/vm/raw_object.h
@@ -2646,18 +2646,22 @@
     data_ = payload + offset_in_bytes;
   }
 
-  // Recopute [data_] based on internal [typed_data_] - needs to be called by GC
-  // whenever the backing store moved.
+  // Recompute [data_] based on internal [typed_data_] - needs to be called by
+  // GC whenever the backing store moved.
   //
   // NOTICE: This method assumes [this] is the forwarded object and the
   // [typed_data_] pointer points to the new backing store. The backing store's
   // fields don't need to be valid - only it's address.
   void RecomputeDataFieldForInternalTypedData() {
+    data_ = DataFieldForInternalTypedData();
+  }
+
+  uint8_t* DataFieldForInternalTypedData() const {
     const intptr_t offset_in_bytes = RawSmiValue(offset_in_bytes_);
     uint8_t* payload =
         reinterpret_cast<uint8_t*>(UntaggedObject::ToAddr(typed_data()) +
                                    UntaggedTypedData::payload_offset());
-    data_ = payload + offset_in_bytes;
+    return payload + offset_in_bytes;
   }
 
   void ValidateInnerPointer() {
diff --git a/tests/corelib/unsigned_shift_test.dart b/tests/corelib/unsigned_shift_test.dart
index c190ff3..ab3220f 100644
--- a/tests/corelib/unsigned_shift_test.dart
+++ b/tests/corelib/unsigned_shift_test.dart
@@ -13,7 +13,7 @@
 
 main() {
   testIntegerShifts();
-  testNonDoubleShifts();
+  testNonIntegerShifts();
   testConstantShifts();
 }
 
@@ -47,18 +47,18 @@
   // If so, it is zero when converted to a fixed precision.
   if (double.infinity is int) {
     int number = (double.infinity as int);
-    Expect.equals(0, number >> 1);
-    Expect.throws(() => 1 >>> number); // infinity > 64.
+    Expect.equals(0, number >>> 1);
+    Expect.equals(0, 1 >>> number); // infinity > 64.
   }
 }
 
-void testNonDoubleShifts() {
+void testNonIntegerShifts() {
   double n = 0.0;
   n >>> 1; //# 01: compile-time error
   for (dynamic number in [0.0, 1.0, 2.4, -2.4, double.infinity, double.nan]) {
     if (number is! int) {
-      Expect.throws(() => number >>> 1);
-      Expect.throws(() => 1 >>> number);
+      Expect.throws(() => number >>> 1); //# 07: ok
+      Expect.throws(() => 1 >>> number); //# 08: ok
     }
   }
 }
diff --git a/tests/corelib_2/unsigned_shift_test.dart b/tests/corelib_2/unsigned_shift_test.dart
index c190ff3..ab3220f 100644
--- a/tests/corelib_2/unsigned_shift_test.dart
+++ b/tests/corelib_2/unsigned_shift_test.dart
@@ -13,7 +13,7 @@
 
 main() {
   testIntegerShifts();
-  testNonDoubleShifts();
+  testNonIntegerShifts();
   testConstantShifts();
 }
 
@@ -47,18 +47,18 @@
   // If so, it is zero when converted to a fixed precision.
   if (double.infinity is int) {
     int number = (double.infinity as int);
-    Expect.equals(0, number >> 1);
-    Expect.throws(() => 1 >>> number); // infinity > 64.
+    Expect.equals(0, number >>> 1);
+    Expect.equals(0, 1 >>> number); // infinity > 64.
   }
 }
 
-void testNonDoubleShifts() {
+void testNonIntegerShifts() {
   double n = 0.0;
   n >>> 1; //# 01: compile-time error
   for (dynamic number in [0.0, 1.0, 2.4, -2.4, double.infinity, double.nan]) {
     if (number is! int) {
-      Expect.throws(() => number >>> 1);
-      Expect.throws(() => 1 >>> number);
+      Expect.throws(() => number >>> 1); //# 07: ok
+      Expect.throws(() => 1 >>> number); //# 08: ok
     }
   }
 }
diff --git a/tests/dartdevc/container_test.dart b/tests/dartdevc/container_test.dart
deleted file mode 100644
index 54d2165..0000000
--- a/tests/dartdevc/container_test.dart
+++ /dev/null
@@ -1,38 +0,0 @@
-// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// Tests that evaluation containers aren't renamed by DDC.
-
-import 'dart:_foreign_helper' as helper show JS;
-
-import 'package:expect/expect.dart';
-
-class T {
-  final int T$Eval = 0;
-  final int S$Eval = 0;
-  String get realT$Eval => helper.JS<String>('', 'T\$Eval.toString()');
-  String get realS$Eval => helper.JS<String>('', 'S\$Eval.toString()');
-}
-
-class T$Eval {}
-
-void main() {
-  var T$Eval = T();
-  var S$Eval = T$Eval;
-
-  var container1 = helper.JS<String>('', 'T\$Eval.toString()');
-  var container2 = helper.JS<String>('', 'S\$Eval.toString()');
-
-  // Evaluation containers are JS Objects. Ensure they aren't shadowed by JS
-  // symbols or Dart constructs.
-  Expect.equals('[object Object]', '$container1');
-  Expect.equals('[object Object]', '$container2');
-
-  Expect.equals("Instance of 'T'", T$Eval.toString());
-  Expect.equals(T$Eval.T$Eval, 0);
-  Expect.equals(T$Eval.S$Eval, 0);
-  Expect.notEquals(T$Eval.toString(), container1);
-  Expect.equals(T$Eval.realT$Eval, container1);
-  Expect.equals(T$Eval.realS$Eval, container2);
-}
diff --git a/tools/VERSION b/tools/VERSION
index 150d415..b39a857 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 13
 PATCH 0
-PRERELEASE 121
+PRERELEASE 122
 PRERELEASE_PATCH 0
\ No newline at end of file