diff --git a/pkg/front_end/test/incremental_bulk_compiler_full.dart b/pkg/front_end/test/incremental_bulk_compiler_full.dart
index c39739d..93c39b2 100644
--- a/pkg/front_end/test/incremental_bulk_compiler_full.dart
+++ b/pkg/front_end/test/incremental_bulk_compiler_full.dart
@@ -51,7 +51,7 @@
   IncrementalCompiler compiler;
 }
 
-CompilerOptions getOptions(bool strong) {
+CompilerOptions getOptions() {
   final Uri sdkRoot = computePlatformBinariesLocation(forceBuildDir: true);
   var options = new CompilerOptions()
     ..sdkRoot = sdkRoot
@@ -59,13 +59,8 @@
     ..omitPlatform = true
     ..onDiagnostic = (DiagnosticMessage message) {
       // Ignored.
-    }
-    ..legacyMode = !strong;
-  if (strong) {
-    options.sdkSummary = sdkRoot.resolve("vm_platform_strong.dill");
-  } else {
-    options.sdkSummary = sdkRoot.resolve("vm_platform.dill");
-  }
+    };
+  options.sdkSummary = sdkRoot.resolve("vm_platform_strong.dill");
   return options;
 }
 
@@ -83,7 +78,7 @@
     List<int> oneShotSerialized;
     try {
       IncrementalCompiler compiler =
-          new IncrementalKernelGenerator(getOptions(true), uri);
+          new IncrementalKernelGenerator(getOptions(), uri);
       oneShotSerialized = util.postProcess(await compiler.computeDelta());
     } catch (e) {
       oneShotFailed = true;
@@ -95,8 +90,7 @@
     try {
       globalDebuggingNames = new NameSystem();
       if (context.compiler == null) {
-        context.compiler =
-            new IncrementalKernelGenerator(getOptions(true), uri);
+        context.compiler = new IncrementalKernelGenerator(getOptions(), uri);
       }
       Component bulkCompiledComponent = await context.compiler
           .computeDelta(entryPoints: [uri], fullComponent: true);
@@ -111,8 +105,7 @@
     try {
       globalDebuggingNames = new NameSystem();
       if (context.compiler == null) {
-        context.compiler =
-            new IncrementalKernelGenerator(getOptions(true), uri);
+        context.compiler = new IncrementalKernelGenerator(getOptions(), uri);
       }
       Component bulkCompiledComponent = await context.compiler
           .computeDelta(entryPoints: [uri], fullComponent: true);
diff --git a/pkg/front_end/test/incremental_dart2js_load_from_dill_test.dart b/pkg/front_end/test/incremental_dart2js_load_from_dill_test.dart
index cf270cb..f1469a1 100644
--- a/pkg/front_end/test/incremental_dart2js_load_from_dill_test.dart
+++ b/pkg/front_end/test/incremental_dart2js_load_from_dill_test.dart
@@ -3,16 +3,21 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async' show Future;
+
 import 'dart:io' show Directory, File;
 
 import 'package:expect/expect.dart' show Expect;
+
 import 'package:front_end/src/compute_platform_binaries_location.dart'
     show computePlatformBinariesLocation;
+
 import 'package:kernel/binary/ast_from_binary.dart' show BinaryBuilder;
+
 import 'package:kernel/kernel.dart' show Component;
+import 'package:kernel/target/targets.dart';
 
 import 'incremental_load_from_dill_test.dart'
-    show normalCompile, initializedCompile, checkIsEqual;
+    show checkIsEqual, getOptions, initializedCompile, normalCompile;
 
 Directory outDir;
 
@@ -36,13 +41,16 @@
   Uri nonexisting = outDir.uri.resolve("dart2js.nonexisting.dill");
 
   // Compile dart2js without initializing from dill.
+  // Note: Use none-target to avoid mismatches in "interface target" caused by
+  // type inference occurring before or after mixin transformation.
   Stopwatch stopwatch = new Stopwatch()..start();
-  await normalCompile(dart2jsUrl, normalDill);
+  await normalCompile(dart2jsUrl, normalDill,
+      options: getOptions()..target = new NoneTarget(new TargetFlags()));
   print("Normal compile took ${stopwatch.elapsedMilliseconds} ms");
   {
     // Check that we don't include the source from files from the sdk.
     final Uri sdkRoot = computePlatformBinariesLocation(forceBuildDir: true);
-    Uri platformUri = sdkRoot.resolve("vm_platform.dill");
+    Uri platformUri = sdkRoot.resolve("vm_platform_strong.dill");
     Component cSdk = new Component();
     new BinaryBuilder(new File.fromUri(platformUri).readAsBytesSync(),
             disableLazyReading: false)
@@ -65,7 +73,7 @@
   }
 
   // Compile dart2js, initializing from the just-compiled dill,
-  // a nonexisting file and a dill file that isn't valid.
+  // a nonexisting file.
   for (List<Object> initializationData in [
     [normalDill, true],
     [nonexisting, false],
@@ -74,7 +82,8 @@
     bool initializeExpect = initializationData[1];
     stopwatch.reset();
     bool initializeResult = await initializedCompile(
-        dart2jsUrl, fullDillFromInitialized, initializeWith, [invalidateUri]);
+        dart2jsUrl, fullDillFromInitialized, initializeWith, [invalidateUri],
+        options: getOptions()..target = new NoneTarget(new TargetFlags()));
     Expect.equals(initializeResult, initializeExpect);
     print("Initialized compile(s) from ${initializeWith.pathSegments.last} "
         "took ${stopwatch.elapsedMilliseconds} ms");
@@ -88,7 +97,8 @@
     // Also try without invalidating anything.
     stopwatch.reset();
     initializeResult = await initializedCompile(
-        dart2jsUrl, fullDillFromInitialized, initializeWith, []);
+        dart2jsUrl, fullDillFromInitialized, initializeWith, [],
+        options: getOptions()..target = new NoneTarget(new TargetFlags()));
     Expect.equals(initializeExpect, initializeResult);
     print("Initialized compile(s) from ${initializeWith.pathSegments.last} "
         "took ${stopwatch.elapsedMilliseconds} ms");
diff --git a/pkg/front_end/test/incremental_load_from_dill_test.dart b/pkg/front_end/test/incremental_load_from_dill_test.dart
index a2ec791..3c68a61 100644
--- a/pkg/front_end/test/incremental_load_from_dill_test.dart
+++ b/pkg/front_end/test/incremental_load_from_dill_test.dart
@@ -116,14 +116,12 @@
         await basicTest(
           map["sources"],
           map["entry"],
-          map["strong"],
           map["invalidate"],
           data.outDir,
         );
         break;
       case "newworld":
         await newWorldTest(
-          map["strong"],
           map["worlds"],
           map["modules"],
           map["omitPlatform"],
@@ -136,7 +134,7 @@
   }
 }
 
-Future<Null> basicTest(YamlMap sourceFiles, String entryPoint, bool strong,
+Future<Null> basicTest(YamlMap sourceFiles, String entryPoint,
     YamlList invalidate, Directory outDir) async {
   Uri entryPointUri = outDir.uri.resolve(entryPoint);
   Set<String> invalidateFilenames =
@@ -169,7 +167,7 @@
   Uri initializedOutput = outDir.uri.resolve("full_from_initialized.dill");
 
   Stopwatch stopwatch = new Stopwatch()..start();
-  CompilerOptions options = getOptions(strong);
+  CompilerOptions options = getOptions();
   if (packagesUri != null) {
     options.packagesFileUri = packagesUri;
   }
@@ -177,7 +175,7 @@
   print("Normal compile took ${stopwatch.elapsedMilliseconds} ms");
 
   stopwatch.reset();
-  options = getOptions(strong);
+  options = getOptions();
   if (packagesUri != null) {
     options.packagesFileUri = packagesUri;
   }
@@ -196,7 +194,7 @@
 }
 
 Future<Map<String, List<int>>> createModules(
-    Map module, final List<int> sdkSummaryData, bool strong) async {
+    Map module, final List<int> sdkSummaryData) async {
   final Uri base = Uri.parse("org-dartlang-test:///");
   final Uri sdkSummary = base.resolve("vm_platform.dill");
 
@@ -227,7 +225,7 @@
         moduleSources.add(uri);
       }
     }
-    CompilerOptions options = getOptions(strong);
+    CompilerOptions options = getOptions();
     options.fileSystem = fs;
     options.sdkRoot = null;
     options.sdkSummary = sdkSummary;
@@ -261,18 +259,12 @@
   return moduleResult;
 }
 
-Future<Null> newWorldTest(
-    bool strong, List worlds, Map modules, bool omitPlatform) async {
+Future<Null> newWorldTest(List worlds, Map modules, bool omitPlatform) async {
   final Uri sdkRoot = computePlatformBinariesLocation(forceBuildDir: true);
   final Uri base = Uri.parse("org-dartlang-test:///");
   final Uri sdkSummary = base.resolve("vm_platform.dill");
   final Uri initializeFrom = base.resolve("initializeFrom.dill");
-  Uri platformUri;
-  if (strong) {
-    platformUri = sdkRoot.resolve("vm_platform_strong.dill");
-  } else {
-    platformUri = sdkRoot.resolve("vm_platform.dill");
-  }
+  Uri platformUri = sdkRoot.resolve("vm_platform_strong.dill");
   final List<int> sdkSummaryData =
       await new File.fromUri(platformUri).readAsBytes();
 
@@ -287,7 +279,7 @@
   Map<String, Component> moduleComponents;
   Component sdk;
   if (modules != null) {
-    moduleData = await createModules(modules, sdkSummaryData, strong);
+    moduleData = await createModules(modules, sdkSummaryData);
     sdk = newestWholeComponent = new Component();
     new BinaryBuilder(sdkSummaryData, filename: null, disableLazyReading: false)
         .readComponent(newestWholeComponent);
@@ -368,7 +360,7 @@
     }
 
     if (brandNewWorld) {
-      options = getOptions(strong);
+      options = getOptions();
       options.fileSystem = fs;
       options.sdkRoot = null;
       options.sdkSummary = sdkSummary;
@@ -745,11 +737,11 @@
   Expect.equals(a.length, b.length);
 }
 
-CompilerOptions getOptions(bool strong) {
+CompilerOptions getOptions() {
   final Uri sdkRoot = computePlatformBinariesLocation(forceBuildDir: true);
   CompilerOptions options = new CompilerOptions()
     ..sdkRoot = sdkRoot
-    ..target = new VmTarget(new TargetFlags(legacyMode: !strong))
+    ..target = new VmTarget(new TargetFlags())
     ..librariesSpecificationUri = Uri.base.resolve("sdk/lib/libraries.json")
     ..omitPlatform = true
     ..onDiagnostic = (DiagnosticMessage message) {
@@ -758,19 +750,14 @@
         Expect.fail(
             "Unexpected error: ${message.plainTextFormatted.join('\n')}");
       }
-    }
-    ..legacyMode = !strong;
-  if (strong) {
-    options.sdkSummary = sdkRoot.resolve("vm_platform_strong.dill");
-  } else {
-    options.sdkSummary = sdkRoot.resolve("vm_platform.dill");
-  }
+    };
+  options.sdkSummary = sdkRoot.resolve("vm_platform_strong.dill");
   return options;
 }
 
 Future<bool> normalCompile(Uri input, Uri output,
     {CompilerOptions options}) async {
-  options ??= getOptions(false);
+  options ??= getOptions();
   TestIncrementalCompiler compiler =
       new TestIncrementalCompiler(options, input);
   Component component = await compiler.computeDelta();
@@ -783,7 +770,7 @@
 Future<bool> initializedCompile(
     Uri input, Uri output, Uri initializeWith, List<Uri> invalidateUris,
     {CompilerOptions options}) async {
-  options ??= getOptions(false);
+  options ??= getOptions();
   TestIncrementalCompiler compiler =
       new TestIncrementalCompiler(options, input, initializeWith);
   for (Uri invalidateUri in invalidateUris) {
diff --git a/pkg/front_end/test/incremental_load_from_invalid_dill_test.dart b/pkg/front_end/test/incremental_load_from_invalid_dill_test.dart
index 0d9a84e..f108317 100644
--- a/pkg/front_end/test/incremental_load_from_invalid_dill_test.dart
+++ b/pkg/front_end/test/incremental_load_from_invalid_dill_test.dart
@@ -132,7 +132,7 @@
     errorMessages = <DiagnosticMessage>[];
     warningMessages = <DiagnosticMessage>[];
     fs = new MemoryFileSystem(base);
-    options = getOptions(true);
+    options = getOptions();
 
     options.fileSystem = fs;
     options.sdkRoot = null;
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/calculated_bounds_no_strongmode.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/calculated_bounds_no_strongmode.yaml
index 9b471de..f884677 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/calculated_bounds_no_strongmode.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/calculated_bounds_no_strongmode.yaml
@@ -2,12 +2,11 @@
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE.md file.
 
-# Test compiling in non-strong-mode from source and initializing from dill.
+# Test compiling from source and initializing from dill.
 # Make sure that any inference if done in the same way.
 
 type: basic
 entry: a.dart
-strong: false
 invalidate:
   - a.dart
 sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules.yaml
index ba6a85f..74d1d07 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules.yaml
@@ -6,7 +6,6 @@
 # Compile again with changing modules.
 
 type: newworld
-strong: true
 modules:
   example_0.1.0:
     example_0.1.0/a.dart: |
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_2.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_2.yaml
index 4d0a193..f2a10a8 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_2.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_2.yaml
@@ -6,7 +6,6 @@
 # Compile again with changing modules.
 
 type: newworld
-strong: true
 modules:
   example_1:
     example_1/a.dart: |
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml
index 7e64c8c..c009ea1 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml
@@ -6,7 +6,6 @@
 # Compile again with changing modules.
 
 type: newworld
-strong: true
 modules:
   foo:
     foo/foo.dart: |
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/cleans_up_uritosource_non_package_unreferenced_libraries.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/cleans_up_uritosource_non_package_unreferenced_libraries.yaml
index 08f0a4c..8c256a6 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/cleans_up_uritosource_non_package_unreferenced_libraries.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/cleans_up_uritosource_non_package_unreferenced_libraries.yaml
@@ -7,7 +7,6 @@
 # also have been removed from the uri to sources.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/cleans_up_uritosource_unreferenced_package_library.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/cleans_up_uritosource_unreferenced_package_library.yaml
index ef7857f..adee8ad 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/cleans_up_uritosource_unreferenced_package_library.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/cleans_up_uritosource_unreferenced_package_library.yaml
@@ -8,7 +8,6 @@
 # removed from the uri to sources.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/constant_set_literal.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/constant_set_literal.yaml
index 4b1c653..d8ddd8d 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/constant_set_literal.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/constant_set_literal.yaml
@@ -5,7 +5,6 @@
 # Test that constant set literals works as expected.
 
 type: newworld
-strong: true
 worlds:
   - entry: "main.dart"
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/deferred_library.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/deferred_library.yaml
index 7ea4cc0..a1d9f4b 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/deferred_library.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/deferred_library.yaml
@@ -7,7 +7,6 @@
 
 type: basic
 entry: a.dart
-strong: false
 invalidate:
 sources:
   a.dart: |
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/deleting_file.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/deleting_file.yaml
index 2933c37..dea1937 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/deleting_file.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/deleting_file.yaml
@@ -7,7 +7,6 @@
 # we should keep getting an error.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     sources:
@@ -24,7 +23,6 @@
     expectedLibraryCount: 2
   - entry: main.dart
     errors: true
-    warnings: true
     invalidate:
       - b.dart
     sources:
@@ -37,7 +35,6 @@
     expectedLibraryCount: 1
   - entry: main.dart
     errors: true
-    warnings: true
     checkInvalidatedFiles: false
     worldType: updated
     invalidate:
@@ -52,7 +49,6 @@
     expectedLibraryCount: 1
   - entry: main.dart
     errors: true
-    warnings: true
     checkInvalidatedFiles: false
     worldType: updated
     invalidate:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/disappearing_library.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/disappearing_library.yaml
index a00341b..75a951b 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/disappearing_library.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/disappearing_library.yaml
@@ -8,7 +8,6 @@
 # of the library list --- initializing from the dill with n libraries.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/disappearing_package.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/disappearing_package.yaml
index 9e236c1..4790a02 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/disappearing_package.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/disappearing_package.yaml
@@ -8,7 +8,6 @@
 # but shouldn't cause trouble, nor be included in the output.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_main.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_main.yaml
index 5bd270e..f5ac43a 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_main.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_main.yaml
@@ -7,7 +7,6 @@
 # should still be included in the output.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_main_with_errors.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_main_with_errors.yaml
index 2360641..828f103 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_main_with_errors.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_main_with_errors.yaml
@@ -7,7 +7,6 @@
 # should still be included in the output - even if there's errors in main.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_no_main.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_no_main.yaml
index 02a57de..fd5d0d5 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_no_main.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/entry_not_package_url_no_main.yaml
@@ -7,7 +7,6 @@
 # should still be included in the output - even if there's no main.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/expression_calculation_with_error.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/expression_calculation_with_error.yaml
index b426a33..9baf55e 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/expression_calculation_with_error.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/expression_calculation_with_error.yaml
@@ -9,7 +9,6 @@
 # error.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/flutter_mixin_failure_1.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/flutter_mixin_failure_1.yaml
index 1a79746..1e22f39 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/flutter_mixin_failure_1.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/flutter_mixin_failure_1.yaml
@@ -5,7 +5,6 @@
 # Regression test from flutter.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/initialize_with_file_then_use_type.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/initialize_with_file_then_use_type.yaml
index e45af03..2efee99 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/initialize_with_file_then_use_type.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/initialize_with_file_then_use_type.yaml
@@ -9,7 +9,6 @@
 # by the class hierarchy.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/initialize_with_unused_package_then_use_type.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/initialize_with_unused_package_then_use_type.yaml
index 85937b6..e34eff2 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/initialize_with_unused_package_then_use_type.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/initialize_with_unused_package_then_use_type.yaml
@@ -10,7 +10,6 @@
 # hierarchy.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_export_of_main.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_export_of_main.yaml
index 07e5102..768fd3c 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_export_of_main.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_export_of_main.yaml
@@ -6,7 +6,6 @@
 
 type: basic
 entry: a.dart
-strong: true
 invalidate:
   - a.dart
 sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part.yaml
index 1d8be7f..da20971 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part.yaml
@@ -6,7 +6,6 @@
 # URI.
 
 type: newworld
-strong: false
 worlds:
   - entry: "package:example/main.dart"
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_as_file.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_as_file.yaml
index eae0ae4..60327f4 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_as_file.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_as_file.yaml
@@ -6,7 +6,6 @@
 
 type: basic
 entry: "package:example/main.dart"
-strong: false
 invalidate:
   - pkg/example/b.dart
 sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_as_package.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_as_package.yaml
index 19816ca..ccbe383 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_as_package.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_as_package.yaml
@@ -6,7 +6,6 @@
 
 type: basic
 entry: "package:example/main.dart"
-strong: false
 invalidate:
   - "package:example/b.dart"
 sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_from_package_url_as_file.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_from_package_url_as_file.yaml
index d5a757b..15d82ee 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_from_package_url_as_file.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_from_package_url_as_file.yaml
@@ -7,7 +7,6 @@
 
 type: basic
 entry: "package:example/main.dart"
-strong: false
 invalidate:
   - pkg/example/b.dart
 sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_from_package_url_as_package.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_from_package_url_as_package.yaml
index 149b1ae..2bb9c88 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_from_package_url_as_package.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_package_part_from_package_url_as_package.yaml
@@ -7,7 +7,6 @@
 
 type: basic
 entry: "package:example/main.dart"
-strong: false
 invalidate:
   - "package:example/b.dart"
 sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_part.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_part.yaml
index 8ff940e..4b88157 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_part.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidate_part.yaml
@@ -6,7 +6,6 @@
 
 type: basic
 entry: a.dart
-strong: true
 invalidate:
   - b.dart
 sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidation_across_compile_time_error.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidation_across_compile_time_error.yaml
index c627364..2313785 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/invalidation_across_compile_time_error.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/invalidation_across_compile_time_error.yaml
@@ -11,7 +11,6 @@
 # that it pulled in should be included.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/load_from_component_explicitly_import_dart_core.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/load_from_component_explicitly_import_dart_core.yaml
index 649545e..6b88d9a 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/load_from_component_explicitly_import_dart_core.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/load_from_component_explicitly_import_dart_core.yaml
@@ -10,7 +10,6 @@
 # the parameter type 'dart.core::String'".
 
 type: newworld
-strong: true
 omitPlatform: false
 worlds:
   - entry: main.dart
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/mixin_from_sdk.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/mixin_from_sdk.yaml
index 30d267a..51be325 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/mixin_from_sdk.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/mixin_from_sdk.yaml
@@ -8,7 +8,6 @@
 
 type: basic
 entry: a.dart
-strong: true
 invalidate:
   - a.dart
 sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/mixin_inferrer_error.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/mixin_inferrer_error.yaml
index e571850..e760b10 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/mixin_inferrer_error.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/mixin_inferrer_error.yaml
@@ -6,7 +6,6 @@
 # and now swallowed somewhere when done in the incremental compiler.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/multiple_entriepoints.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/multiple_entriepoints.yaml
index 83c53a0..0577118 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/multiple_entriepoints.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/multiple_entriepoints.yaml
@@ -6,7 +6,6 @@
 # results in getting both libraries (aka that multiple entry points work).
 
 type: newworld
-strong: true
 worlds:
   - entry:
       - a.dart
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/no_invalidate_on_export_of_main.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/no_invalidate_on_export_of_main.yaml
index d336e98..5f3ac3c 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/no_invalidate_on_export_of_main.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/no_invalidate_on_export_of_main.yaml
@@ -7,7 +7,6 @@
 
 type: basic
 entry: a.dart
-strong: true
 invalidate:
 sources:
   a.dart: |
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_1.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_1.yaml
index e306e5a..8d884a3 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_1.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_1.yaml
@@ -5,7 +5,6 @@
 # Compile a hello world program, check that omit platform works as expected.
 
 type: newworld
-strong: true
 omitPlatform: true
 worlds:
   - entry: main.dart
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_2.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_2.yaml
index e1a42a8a..071eacd 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_2.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_2.yaml
@@ -6,7 +6,6 @@
 # Omit platform is true by default in tests.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_3.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_3.yaml
index b649bbd..450377b 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_3.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/omit_platform_works_3.yaml
@@ -7,7 +7,6 @@
 # component again etc.
 
 type: newworld
-strong: true
 omitPlatform: false
 worlds:
   - entry: main.dart
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/outline_only.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/outline_only.yaml
index 5bfb458..59a9e45 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/outline_only.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/outline_only.yaml
@@ -5,7 +5,6 @@
 # Compile an application with the option of only getting an outline.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/outline_only_2.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/outline_only_2.yaml
index 0105f44..94b1a83 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/outline_only_2.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/outline_only_2.yaml
@@ -6,7 +6,6 @@
 # This is a reproduction of http://dartbug.com/36498.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/regress_35215.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/regress_35215.yaml
index 5fd397a..b906cba 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/regress_35215.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/regress_35215.yaml
@@ -7,7 +7,6 @@
 # exist in the old library.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_1.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_1.yaml
index 0be7810..fb57969 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_1.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_1.yaml
@@ -7,7 +7,6 @@
 # we keep getting errors. Once we fix it, we no longer get errors.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_2.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_2.yaml
index 468566d..91ce7a3 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_2.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_2.yaml
@@ -7,7 +7,6 @@
 # we keep getting errors. Once we fix it, we no longer get errors.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_3.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_3.yaml
index 5375fd6..1c74c07 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_3.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_3.yaml
@@ -7,7 +7,6 @@
 # we keep getting errors. Once we fix it, we no longer get errors.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_4.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_4.yaml
index 994f2c6..8342cbd 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_4.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_4.yaml
@@ -7,7 +7,6 @@
 # we keep getting errors. Once we fix it, we no longer get errors.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_5.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_5.yaml
index c5164e2..65f2282 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_5.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/reissue_errors_5.yaml
@@ -7,7 +7,6 @@
 # we keep getting errors. Once we fix it, we no longer get errors.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/remove_import_with_error.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/remove_import_with_error.yaml
index fb8b511..5965f18 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/remove_import_with_error.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/remove_import_with_error.yaml
@@ -7,7 +7,6 @@
 # invalidating a. Compiling this should not result in any errors.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     errors: true
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/strongmode_mixins.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/strongmode_mixins.yaml
index 1981950..f644133 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/strongmode_mixins.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/strongmode_mixins.yaml
@@ -2,13 +2,12 @@
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE.md file.
 
-# Compile in strong mode. Invalidate a file so type inferrer starts
+# Compile. Invalidate a file so type inferrer starts
 # on something compiled from source and (potentially) goes into
 # something loaded from dill.
 
 type: basic
 entry: a.dart
-strong: true
 invalidate:
   - a.dart
 sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/strongmode_mixins_2.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/strongmode_mixins_2.yaml
index 61d783f..9238c66 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/strongmode_mixins_2.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/strongmode_mixins_2.yaml
@@ -2,11 +2,10 @@
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE.md file.
 
-# Compile in strong mode. Use mixins.
+# Compile. Use mixins.
 
 type: basic
 entry: a.dart
-strong: true
 invalidate:
   - a.dart
 sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/unused_file.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/unused_file.yaml
index a2c5739..e7182de 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/unused_file.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/unused_file.yaml
@@ -8,7 +8,6 @@
 # but shouldn't cause trouble, nor be included in the output.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_1.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_1.yaml
index 7bb3ab1..0a24fa7 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_1.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_1.yaml
@@ -8,7 +8,6 @@
 # but shouldn't cause trouble, nor be included in the output.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_2.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_2.yaml
index 00cd03f..ad7756f 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_2.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_2.yaml
@@ -8,7 +8,6 @@
 # but shouldn't cause trouble, nor be included in the output.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_3.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_3.yaml
index 1c79496..ed1f6ab 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_3.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_3.yaml
@@ -8,7 +8,6 @@
 # The output should not include the old package.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_4.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_4.yaml
index c7a7491..5cb7d9c 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_4.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_4.yaml
@@ -7,7 +7,6 @@
 # This should be an error.
 
 type: newworld
-strong: false
 worlds:
   - entry: main.dart
     sources:
@@ -32,5 +31,4 @@
     sources:
       .packages:
     errors: true
-    warnings: true
     expectedLibraryCount: 1
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_uri.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_uri.yaml
index cf01000..f716e96 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_uri.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/updated_package_uri.yaml
@@ -7,7 +7,6 @@
 # should now be relative to the new .packages file.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_1.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_1.yaml
index 14b0a58..9f3b66a 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_1.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_1.yaml
@@ -7,7 +7,6 @@
 # Loading from such a dill is ok too.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_2.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_2.yaml
index bbcc110..50f16a6 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_2.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_2.yaml
@@ -7,7 +7,6 @@
 # Loading from such a dill is ok too.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_3.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_3.yaml
index 0402343..6d8eb3f 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_3.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_3.yaml
@@ -7,7 +7,6 @@
 # Loading from such a dill is ok too.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_4.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_4.yaml
index df8a598..1af29a8 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_4.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_4.yaml
@@ -8,7 +8,6 @@
 # Loading from such a dill is ok too.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources:
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_5.yaml b/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_5.yaml
index bd55d81..9aa7ede 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_5.yaml
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/working_with_synthetic_libraries_5.yaml
@@ -7,7 +7,6 @@
 # Loading from such a dill is ok too.
 
 type: newworld
-strong: true
 worlds:
   - entry: main.dart
     sources: