Fuse --strong into --preview-dart-2 option.

packages/flutter_tools/gradle/flutter.gradle

@@ -261,11 +261,6 @@ class FlutterPlugin implements Plugin<Project> {
             previewDart2Value = project.property('preview-dart-2')
         }
 
-        Boolean strongModeValue = false
-        if (project.hasProperty('strong')) {
-            strongModeValue = project.property('strong')
-        }
-
         String extraFrontEndOptionsValue = null
         if (project.hasProperty('extra-front-end-options')) {
             extraFrontEndOptionsValue = project.property('extra-front-end-options')
@@ -304,7 +299,6 @@ class FlutterPlugin implements Plugin<Project> {
                 localEngineSrcPath this.localEngineSrcPath
                 targetPath target
                 previewDart2 previewDart2Value
-                strongMode strongModeValue
                 preferSharedLibrary preferSharedLibraryValue
                 targetPlatform targetPlatformValue
                 sourceDir project.file(project.flutter.source)
@@ -320,7 +314,6 @@ class FlutterPlugin implements Plugin<Project> {
                 localEngineSrcPath this.localEngineSrcPath
                 targetPath target
                 previewDart2 previewDart2Value
-                strongMode strongModeValue
                 preferSharedLibrary preferSharedLibraryValue
                 targetPlatform targetPlatformValue
                 sourceDir project.file(project.flutter.source)
@@ -357,8 +350,6 @@ abstract class BaseFlutterTask extends DefaultTask {
     @Optional @Input
     Boolean previewDart2
     @Optional @Input
-    Boolean strongMode
-    @Optional @Input
     Boolean preferSharedLibrary
     @Optional @Input
     String targetPlatform
@@ -401,9 +392,6 @@ abstract class BaseFlutterTask extends DefaultTask {
                 if (previewDart2) {
                     args "--preview-dart-2"
                 }
-		if (strongMode) {
-                    args "--strong"
-                }
                 if (extraFrontEndOptions != null) {
                     args "--extra-front-end-options", "${extraFrontEndOptions}"
                 }
@@ -433,9 +421,6 @@ abstract class BaseFlutterTask extends DefaultTask {
             if (previewDart2) {
                 args "--preview-dart-2"
             }
-            if (strongMode) {
-                args "--strong"
-            }
 
             args "--output-file", "${intermediateDir}/app.flx"
             if (buildMode != "debug") {

packages/flutter_tools/lib/src/android/gradle.dart

@@ -291,12 +291,11 @@ Future<Null> _buildGradleProjectV2(String gradle, BuildInfo buildInfo, String ta
   }
   if (buildInfo.previewDart2) {
     command.add('-Ppreview-dart-2=true');
-  if (buildInfo.strongMode)
     command.add('-Pstrong=true');
-  if (buildInfo.extraFrontEndOptions != null)
-    command.add('-Pextra-front-end-options=${buildInfo.extraFrontEndOptions}');
-  if (buildInfo.extraGenSnapshotOptions != null)
-    command.add('-Pextra-gen-snapshot-options=${buildInfo.extraGenSnapshotOptions}');
+    if (buildInfo.extraFrontEndOptions != null)
+      command.add('-Pextra-front-end-options=${buildInfo.extraFrontEndOptions}');
+    if (buildInfo.extraGenSnapshotOptions != null)
+      command.add('-Pextra-gen-snapshot-options=${buildInfo.extraGenSnapshotOptions}');
   }
   if (buildInfo.preferSharedLibrary && androidSdk.ndkCompiler != null) {
     command.add('-Pprefer-shared-library=true');

packages/flutter_tools/lib/src/artifacts.dart

@@ -21,7 +21,6 @@ enum Artifact {
   vmSnapshotData,
   isolateSnapshotData,
   platformKernelDill,
-  platformKernelStrongDill,
   platformLibrariesJson,
   flutterPatchedSdkPath,
   frontendServerSnapshotForEngineDartSdk,
@@ -47,8 +46,6 @@ String _artifactToFileName(Artifact artifact) {
     case Artifact.isolateSnapshotData:
       return 'isolate_snapshot.bin';
     case Artifact.platformKernelDill:
-      return 'platform.dill';
-    case Artifact.platformKernelStrongDill:
       return 'platform_strong.dill';
     case Artifact.platformLibrariesJson:
       return 'libraries.json';
@@ -172,7 +169,6 @@ class CachedArtifacts extends Artifacts {
         final String platformDirName = getNameForTargetPlatform(platform);
         return fs.path.join(engineArtifactsPath, platformDirName, _artifactToFileName(artifact));
       case Artifact.platformKernelDill:
-      case Artifact.platformKernelStrongDill:
         return fs.path.join(_getFlutterPatchedSdkPath(), _artifactToFileName(artifact));
       case Artifact.platformLibrariesJson:
         return fs.path.join(_getFlutterPatchedSdkPath(), 'lib', _artifactToFileName(artifact));
@@ -243,7 +239,6 @@ class LocalEngineArtifacts extends Artifacts {
       case Artifact.vmSnapshotData:
         return fs.path.join(engineOutPath, 'gen', 'flutter', 'lib', 'snapshot', _artifactToFileName(artifact));
       case Artifact.platformKernelDill:
-      case Artifact.platformKernelStrongDill:
         return fs.path.join(_getFlutterPatchedSdkPath(), _artifactToFileName(artifact));
       case Artifact.platformLibrariesJson:
         return fs.path.join(_getFlutterPatchedSdkPath(), 'lib', _artifactToFileName(artifact));

packages/flutter_tools/lib/src/build_info.dart

@@ -12,7 +12,6 @@ import 'globals.dart';
 class BuildInfo {
   const BuildInfo(this.mode, this.flavor,
       {this.previewDart2,
-      this.strongMode,
       this.extraFrontEndOptions,
       this.extraGenSnapshotOptions,
       this.preferSharedLibrary,
@@ -30,9 +29,6 @@ class BuildInfo {
   // Whether build should be done using Dart2 Frontend parser.
   final bool previewDart2;
 
-  // Whether build should use strong mode semantics.
-  final bool strongMode;
-
   /// Extra command-line options for front-end.
   final String extraFrontEndOptions;
 
@@ -72,7 +68,6 @@ class BuildInfo {
   BuildInfo withTargetPlatform(TargetPlatform targetPlatform) =>
       new BuildInfo(mode, flavor,
           previewDart2: previewDart2,
-          strongMode: strongMode,
           extraFrontEndOptions: extraFrontEndOptions,
           extraGenSnapshotOptions: extraGenSnapshotOptions,
           preferSharedLibrary: preferSharedLibrary,

packages/flutter_tools/lib/src/commands/build_aot.dart

@@ -40,7 +40,6 @@ class BuildAotCommand extends BuildSubCommand {
       ..addFlag('interpreter')
       ..addFlag('quiet', defaultsTo: false)
       ..addFlag('preview-dart-2', negatable: false, hide: !verboseHelp)
-      ..addFlag('strong', negatable: false, hide: !verboseHelp)
       ..addOption(FlutterOptions.kExtraFrontEndOptions,
         allowMultiple: true,
         splitCommas: true,
@@ -82,7 +81,6 @@ class BuildAotCommand extends BuildSubCommand {
       outputPath: argResults['output-dir'],
       interpreter: argResults['interpreter'],
       previewDart2: argResults['preview-dart-2'],
-      strongMode: argResults['strong'],
       extraFrontEndOptions: argResults[FlutterOptions.kExtraFrontEndOptions],
       extraGenSnapshotOptions: argResults[FlutterOptions.kExtraGenSnapshotOptions],
       preferSharedLibrary: argResults['prefer-shared-library'],
@@ -114,7 +112,6 @@ Future<String> buildAotSnapshot(
   String outputPath,
   bool interpreter: false,
   bool previewDart2: false,
-  bool strongMode: false,
   List<String> extraFrontEndOptions,
   List<String> extraGenSnapshotOptions,
   bool preferSharedLibrary: false,
@@ -128,7 +125,6 @@ Future<String> buildAotSnapshot(
       outputPath: outputPath,
       interpreter: interpreter,
       previewDart2: previewDart2,
-      strongMode: strongMode,
       extraFrontEndOptions: extraFrontEndOptions,
       extraGenSnapshotOptions: extraGenSnapshotOptions,
       preferSharedLibrary: preferSharedLibrary,
@@ -148,7 +144,6 @@ Future<String> _buildAotSnapshot(
   String outputPath,
   bool interpreter: false,
   bool previewDart2: false,
-  bool strongMode: false,
   List<String> extraFrontEndOptions,
   List<String> extraGenSnapshotOptions,
   bool preferSharedLibrary: false,
@@ -346,19 +341,16 @@ Future<String> _buildAotSnapshot(
       extraFrontEndOptions: extraFrontEndOptions,
       linkPlatformKernelIn : true,
       aot : true,
-      strongMode: strongMode,
     );
     if (mainPath == null) {
       printError('Compiler terminated unexpectedly.');
       return null;
     }
 
-    if (strongMode) {
-      genSnapshotCmd.addAll(<String>[
-        '--reify-generic-functions',
-        '--strong',
-      ]);
-    }
+    genSnapshotCmd.addAll(<String>[
+      '--reify-generic-functions',
+      '--strong',
+    ]);
   }
 
   genSnapshotCmd.add(mainPath);

packages/flutter_tools/lib/src/commands/build_apk.dart

@@ -15,8 +15,7 @@ class BuildApkCommand extends BuildSubCommand {
     usesPubOption();
 
     argParser
-      ..addFlag('preview-dart-2', negatable: false, hide: !verboseHelp)
-      ..addFlag('strong', negatable: false, hide: !verboseHelp)
+      ..addFlag('preview-dart-2', negatable: false,  hide: !verboseHelp)
       ..addFlag('prefer-shared-library', negatable: false,
           help: 'Whether to prefer compiling to a *.so file (android only).')
       ..addOption('target-platform',

packages/flutter_tools/lib/src/commands/build_flx.dart

@@ -21,7 +21,6 @@ class BuildFlxCommand extends BuildSubCommand {
     argParser.addOption('snapshot', defaultsTo: defaultSnapshotPath);
     argParser.addOption('depfile', defaultsTo: defaultDepfilePath);
     argParser.addFlag('preview-dart-2', negatable: false, hide: !verboseHelp);
-    argParser.addFlag('strong', negatable: false, hide: !verboseHelp);
     argParser.addOption('working-dir', defaultsTo: getAssetBuildDirectory());
     argParser.addFlag('report-licensed-packages', help: 'Whether to report the names of all the packages that are included in the application\'s LICENSE file.', defaultsTo: false);
     usesPubOption();
@@ -51,7 +50,6 @@ class BuildFlxCommand extends BuildSubCommand {
       privateKeyPath: argResults['private-key'],
       workingDirPath: argResults['working-dir'],
       previewDart2: argResults['preview-dart-2'],
-      strongMode: argResults['strong'],
       precompiledSnapshot: argResults['precompiled'],
       reportLicensedPackages: argResults['report-licensed-packages']
     );

packages/flutter_tools/lib/src/commands/build_ios.dart

@@ -31,8 +31,6 @@ class BuildIOSCommand extends BuildSubCommand {
         help: 'Codesign the application bundle (only available on device builds).');
     argParser.addFlag('preview-dart-2', negatable: false,
         hide: !verboseHelp);
-    argParser.addFlag('strong', negatable: false,
-        hide: !verboseHelp);
   }
 
   @override

packages/flutter_tools/lib/src/commands/create.dart

@@ -238,7 +238,6 @@ class CreateCommand extends FlutterCommand {
       target: flx.defaultMainPath,
       hasPlugins: generatePlugin,
       previewDart2: false,
-      strongMode: false,
     );
 
     if (argResults['pub']) {

packages/flutter_tools/lib/src/commands/daemon.dart

@@ -374,7 +374,6 @@ class AppDomain extends Domain {
         usesTerminalUI: false,
         applicationBinary: applicationBinary,
         previewDart2: previewDart2,
-        strongMode: strongMode,
         projectRootPath: projectRootPath,
         packagesFilePath: packagesFilePath,
         projectAssets: projectAssets,
@@ -389,7 +388,6 @@ class AppDomain extends Domain {
         usesTerminalUI: false,
         applicationBinary: applicationBinary,
         previewDart2: previewDart2,
-        strongMode: strongMode,
         ipv6: ipv6,
       );
     }

packages/flutter_tools/lib/src/commands/run.dart

@@ -254,7 +254,6 @@ class RunCommand extends RunCommandBase {
           _createDebuggingOptions(), hotMode,
           applicationBinary: argResults['use-application-binary'],
           previewDart2: argResults['preview-dart-2'],
-          strongMode: argResults['strong'],
           projectRootPath: argResults['project-root'],
           packagesFilePath: globalResults['packages'],
           projectAssets: argResults['project-assets'],
@@ -293,9 +292,7 @@ class RunCommand extends RunCommandBase {
     }
 
     final List<FlutterDevice> flutterDevices = devices.map((Device device) {
-      return new FlutterDevice(device,
-                               previewDart2: argResults['preview-dart-2'],
-                               strongMode : argResults['strong']);
+      return new FlutterDevice(device, previewDart2: argResults['preview-dart-2']);
     }).toList();
 
     ResidentRunner runner;
@@ -307,7 +304,6 @@ class RunCommand extends RunCommandBase {
         benchmarkMode: argResults['benchmark'],
         applicationBinary: argResults['use-application-binary'],
         previewDart2: argResults['preview-dart-2'],
-        strongMode: argResults['strong'],
         projectRootPath: argResults['project-root'],
         packagesFilePath: globalResults['packages'],
         projectAssets: argResults['project-assets'],
@@ -322,7 +318,6 @@ class RunCommand extends RunCommandBase {
         traceStartup: traceStartup,
         applicationBinary: argResults['use-application-binary'],
         previewDart2: argResults['preview-dart-2'],
-        strongMode: argResults['strong'],
         stayResident: stayResident,
         ipv6: ipv6,
       );

packages/flutter_tools/lib/src/compile.dart

@@ -60,7 +60,6 @@ Future<String> compile(
     String mainPath,
     bool linkPlatformKernelIn: false,
     bool aot: false,
-    bool strongMode: false,
     List<String> extraFrontEndOptions,
     String incrementalCompilerByteStorePath,
     String packagesPath}) async {
@@ -76,15 +75,13 @@ Future<String> compile(
     frontendServer,
     '--sdk-root',
     sdkRoot,
+    '--strong',
   ];
   if (!linkPlatformKernelIn)
     command.add('--no-link-platform');
   if (aot) {
     command.add('--aot');
   }
-  if (strongMode) {
-    command.add('--strong');
-  }
   if (incrementalCompilerByteStorePath != null) {
     command.add('--incremental');
   }
@@ -121,16 +118,13 @@ Future<String> compile(
 /// The wrapper is intended to stay resident in memory as user changes, reloads,
 /// restarts the Flutter app.
 class ResidentCompiler {
-  ResidentCompiler(this._sdkRoot, {bool strongMode: false})
-    : assert(_sdkRoot != null) {
+  ResidentCompiler(this._sdkRoot) : assert(_sdkRoot != null) {
     // This is a URI, not a file path, so the forward slash is correct even on Windows.
     if (!_sdkRoot.endsWith('/'))
       _sdkRoot = '$_sdkRoot/';
-    _strongMode = strongMode;
   }
 
   String _sdkRoot;
-  bool _strongMode;
   Process _server;
   final _StdoutHandler stdoutHandler = new _StdoutHandler();
 
@@ -165,11 +159,9 @@ class ResidentCompiler {
       frontendServer,
       '--sdk-root',
       _sdkRoot,
-      '--incremental'
+      '--incremental',
+      '--strong'
     ];
-    if (_strongMode) {
-      args.add('--strong');
-    }
     _server = await processManager.start(args);
     _server.stdout
       .transform(UTF8.decoder)

packages/flutter_tools/lib/src/flx.dart

@@ -39,7 +39,6 @@ Future<Null> build({
   String workingDirPath,
   String packagesPath,
   bool previewDart2 : false,
-  bool strongMode : false,
   bool precompiledSnapshot: false,
   bool reportLicensedPackages: false
 }) async {
@@ -74,7 +73,6 @@ Future<Null> build({
       sdkRoot: artifacts.getArtifactPath(Artifact.flutterPatchedSdkPath),
       incrementalCompilerByteStorePath: fs.path.absolute(getIncrementalCompilerByteStoreDirectory()),
       mainPath: fs.file(mainPath).absolute.path,
-      strongMode: strongMode
     );
     if (kernelBinaryFilename == null) {
       throwToolExit('Compiler terminated unexpectedly on $mainPath');
@@ -90,7 +88,6 @@ Future<Null> build({
     privateKeyPath: privateKeyPath,
     workingDirPath: workingDirPath,
     packagesPath: packagesPath,
-    strongMode: strongMode,
     reportLicensedPackages: reportLicensedPackages
   ).then((_) => null);
 }
@@ -104,7 +101,6 @@ Future<List<String>> assemble({
   String privateKeyPath: defaultPrivateKeyPath,
   String workingDirPath,
   String packagesPath,
-  bool strongMode : false,
   bool includeDefaultFonts: true,
   bool reportLicensedPackages: false
 }) async {
@@ -135,9 +131,7 @@ Future<List<String>> assemble({
       .toList();
 
   if (kernelContent != null) {
-    final String platformKernelDill = strongMode ?
-        artifacts.getArtifactPath(Artifact.platformKernelStrongDill) :
-        artifacts.getArtifactPath(Artifact.platformKernelDill);
+    final String platformKernelDill = artifacts.getArtifactPath(Artifact.platformKernelDill);
     zipBuilder.entries[_kKernelKey] = kernelContent;
     zipBuilder.entries[_kPlatformKernelKey] = new DevFSFileContent(fs.file(platformKernelDill));
   }

packages/flutter_tools/lib/src/ios/mac.dart

@@ -264,7 +264,6 @@ Future<XcodeBuildResult> buildXcodeProject({
     target: target,
     hasPlugins: hasFlutterPlugins,
     previewDart2: buildInfo.previewDart2,
-    strongMode: buildInfo.strongMode,
   );
 
   if (hasFlutterPlugins) {

packages/flutter_tools/lib/src/ios/simulators.dart

@@ -392,7 +392,6 @@ class IOSSimulator extends Device {
 
     final BuildInfo debugBuildInfo = new BuildInfo(BuildMode.debug, buildInfo.flavor,
         previewDart2: buildInfo.previewDart2,
-        strongMode: buildInfo.strongMode,
         extraFrontEndOptions: buildInfo.extraFrontEndOptions,
         extraGenSnapshotOptions: buildInfo.extraGenSnapshotOptions,
         preferSharedLibrary: buildInfo.preferSharedLibrary);
@@ -416,8 +415,7 @@ class IOSSimulator extends Device {
       // When running in previewDart2 mode, we still need to run compiler to
       // produce kernel file for the application.
       flx.build(precompiledSnapshot: !buildInfo.previewDart2,
-          previewDart2: buildInfo.previewDart2,
-          strongMode: buildInfo.strongMode);
+          previewDart2: buildInfo.previewDart2);
 
   @override
   Future<bool> stopApp(ApplicationPackage app) async {

packages/flutter_tools/lib/src/ios/xcodeproj.dart

@@ -25,7 +25,6 @@ void updateXcodeGeneratedProperties({
   @required String target,
   @required bool hasPlugins,
   @required bool previewDart2,
-  @required bool strongMode,
 }) {
   final StringBuffer localsBuffer = new StringBuffer();
 
@@ -57,8 +56,6 @@ void updateXcodeGeneratedProperties({
 
   if (previewDart2) {
     localsBuffer.writeln('PREVIEW_DART_2=true');
-  }
-  if (strongMode) {
     localsBuffer.writeln('STRONG=true');
   }
 

packages/flutter_tools/lib/src/resident_runner.dart

@@ -38,12 +38,9 @@ class FlutterDevice {
 
   StreamSubscription<String> _loggingSubscription;
 
-  FlutterDevice(this.device,
-                { bool previewDart2 : false, bool strongMode : false }) {
+  FlutterDevice(this.device, { bool previewDart2 : false }) {
     if (previewDart2)
-      generator = new ResidentCompiler(
-        artifacts.getArtifactPath(Artifact.flutterPatchedSdkPath),
-        strongMode: strongMode);
+      generator = new ResidentCompiler(artifacts.getArtifactPath(Artifact.flutterPatchedSdkPath));
   }
 
   String viewFilter;
@@ -270,8 +267,8 @@ class FlutterDevice {
     }
 
     final Map<String, dynamic> platformArgs = <String, dynamic>{};
-    if (hotRunner.strongMode != null)
-      platformArgs['strong'] = hotRunner.strongMode;
+    if (hotRunner.previewDart2 != null)
+      platformArgs['strong'] = hotRunner.previewDart2;
 
     startEchoingDeviceLog();
 
@@ -333,8 +330,8 @@ class FlutterDevice {
     final Map<String, dynamic> platformArgs = <String, dynamic>{};
     if (coldRunner.traceStartup != null)
       platformArgs['trace-startup'] = coldRunner.traceStartup;
-    if (coldRunner.strongMode != null)
-      platformArgs['strong'] = coldRunner.strongMode;
+    if (coldRunner.previewDart2 != null)
+      platformArgs['strong'] = coldRunner.previewDart2;
 
     startEchoingDeviceLog();
 

packages/flutter_tools/lib/src/run_cold.dart

@@ -21,7 +21,6 @@ class ColdRunner extends ResidentRunner {
     this.traceStartup: false,
     this.applicationBinary,
     this.previewDart2 : false,
-    this.strongMode : false,
     bool stayResident: true,
     bool ipv6: false,
   }) : super(devices,
@@ -34,7 +33,6 @@ class ColdRunner extends ResidentRunner {
   final bool traceStartup;
   final String applicationBinary;
   final bool previewDart2;
-  final bool strongMode;
 
   @override
   Future<int> run({

packages/flutter_tools/lib/src/run_hot.dart

@@ -40,7 +40,6 @@ class HotRunner extends ResidentRunner {
     this.benchmarkMode: false,
     this.applicationBinary,
     this.previewDart2: false,
-    this.strongMode: false,
     this.hostIsIde: false,
     String projectRootPath,
     String packagesFilePath,
@@ -67,7 +66,6 @@ class HotRunner extends ResidentRunner {
   bool _runningFromSnapshot = true;
   bool previewDart2 = false;
   DateTime firstBuildTime;
-  bool strongMode = false;
 
   void _addBenchmarkData(String name, int value) {
     benchmarkData[name] ??= <int>[];

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -163,20 +163,12 @@ abstract class FlutterCommand extends Command<Null> {
     final bool previewDart2 = argParser.options.containsKey('preview-dart-2')
         ? argResults['preview-dart-2']
         : false;
-    final bool strongMode = argParser.options.containsKey('strong')
-        ? argResults['strong']
-        : false;
-    if (strongMode == true && previewDart2 == false) {
-      throw new UsageException(
-          '--strong is valid only when --preview-dart-2 is specified.', null);
-    }
 
     return new BuildInfo(getBuildMode(),
       argParser.options.containsKey('flavor')
         ? argResults['flavor']
         : null,
       previewDart2: previewDart2,
-      strongMode: strongMode,
       extraFrontEndOptions: argParser.options.containsKey(FlutterOptions.kExtraFrontEndOptions)
           ? argResults[FlutterOptions.kExtraFrontEndOptions]
           : null,
@@ -400,16 +392,6 @@ abstract class FlutterCommand extends Command<Null> {
       if (!fs.isFileSync(targetPath))
         throw new ToolExit('Target file "$targetPath" not found.');
     }
-
-    final bool previewDart2 = argParser.options.containsKey('preview-dart-2')
-        ? argResults['preview-dart-2']
-        : false;
-    final bool strongMode = argParser.options.containsKey('strong')
-        ? argResults['strong']
-        : false;
-    if (strongMode == true && previewDart2 == false) {
-      throw new ToolExit('--strong is valid only with --preview-dart-2 option.');
-    }
   }
 
   ApplicationPackageStore applicationPackages;

packages/flutter_tools/lib/src/test/flutter_platform.dart

@@ -209,7 +209,6 @@ class _FlutterPlatform extends PlatformPlugin {
           incrementalCompilerByteStorePath: '' /* not null is enough */,
           mainPath: listenerFile.path,
           packagesPath: PackageMap.globalPackagesPath,
-          strongMode: true,
         );
 
         // bundlePath needs to point to a folder with `platform.dill` file.
@@ -222,7 +221,7 @@ class _FlutterPlatform extends PlatformPlugin {
 
         // copy 'vm_platform_strong.dill' into 'platform.dill'
         final File vmPlatformStrongDill = fs.file(
-          artifacts.getArtifactPath(Artifact.platformKernelStrongDill),
+          artifacts.getArtifactPath(Artifact.platformKernelDill),
         );
         final File platformDill = vmPlatformStrongDill.copySync(
           tempBundleDirectory.childFile('platform.dill').path,
@@ -547,11 +546,12 @@ void main() {
     }
     if (strongMode) {
       command.add('--strong');
+    } else {
+      command.add('--enable-checked-mode');
     }
     command.addAll(<String>[
       '--enable-dart-profiling',
       '--non-interactive',
-      '--enable-checked-mode',
       '--use-test-fonts',
       // '--enable-txt', // enable this to test libtxt rendering
       '--packages=$packages',