diff --git a/pkg/front_end/test/incremental_load_from_dill_suite.dart b/pkg/front_end/test/incremental_load_from_dill_suite.dart
index 29e76fe820a..79b25aa0f4c 100644
--- a/pkg/front_end/test/incremental_load_from_dill_suite.dart
+++ b/pkg/front_end/test/incremental_load_from_dill_suite.dart
@@ -40,12 +40,14 @@ import 'package:front_end/src/fasta/incremental_compiler.dart'
 
 import 'package:front_end/src/fasta/incremental_serializer.dart'
     show IncrementalSerializer;
+import 'package:front_end/src/fasta/kernel/kernel_api.dart';
 
 import 'package:front_end/src/fasta/kernel/utils.dart' show ByteSink;
 
 import 'package:kernel/binary/ast_from_binary.dart' show BinaryBuilder;
 
 import 'package:kernel/binary/ast_to_binary.dart' show BinaryPrinter;
+import 'package:kernel/class_hierarchy.dart';
 
 import 'package:kernel/kernel.dart'
     show
@@ -55,6 +57,7 @@ import 'package:kernel/kernel.dart'
         Field,
         Library,
         LibraryDependency,
+        Member,
         Name,
         Procedure;
 
@@ -608,25 +611,8 @@ Future<Null> newWorldTest(
       }
     }
 
-    Uri uri = data.loadedFrom
-        .resolve(data.loadedFrom.pathSegments.last + ".world.$worldNum.expect");
-    String expected;
-    File file = new File.fromUri(uri);
-    if (context.updateExpectations) {
-      file.writeAsStringSync(actualSerialized);
-    }
-    if (file.existsSync()) {
-      expected = file.readAsStringSync();
-    }
-    if (context.updateExpectations) {
-      file.writeAsStringSync(actualSerialized);
-    } else if (expected != actualSerialized) {
-      String extra = "";
-      if (expected == null) extra = "Expect file did not exist.\n";
-      throw "${extra}Unexpected serialized representation. "
-          "Fix or update $uri to contain the below:\n\n"
-          "$actualSerialized";
-    }
+    checkExpectFile(data, worldNum, context, actualSerialized);
+    checkClassHierarchy(compiler, component, data, worldNum, context);
 
     int nonSyntheticLibraries = countNonSyntheticLibraries(component);
     int nonSyntheticPlatformLibraries =
@@ -848,6 +834,166 @@ Future<Null> newWorldTest(
   }
 }
 
+void checkExpectFile(
+    TestData data, int worldNum, Context context, String actualSerialized) {
+  Uri uri = data.loadedFrom
+      .resolve(data.loadedFrom.pathSegments.last + ".world.$worldNum.expect");
+  String expected;
+  File file = new File.fromUri(uri);
+  if (file.existsSync()) {
+    expected = file.readAsStringSync();
+  }
+  if (expected != actualSerialized) {
+    if (context.updateExpectations) {
+      file.writeAsStringSync(actualSerialized);
+    } else {
+      String extra = "";
+      if (expected == null) extra = "Expect file did not exist.\n";
+      throw "${extra}Unexpected serialized representation. "
+          "Fix or update $uri to contain the below:\n\n"
+          "$actualSerialized";
+    }
+  }
+}
+
+/// Check that the class hierarchy is up-to-date with reality.
+///
+/// This has the option to do expect files, but it's disabled by default
+/// while we're trying to figure out if it's useful or not.
+void checkClassHierarchy(TestIncrementalCompiler compiler, Component component,
+    TestData data, int worldNum, Context context,
+    {bool checkExpectFile: false}) {
+  ClassHierarchy classHierarchy = compiler.getClassHierarchy();
+  if (classHierarchy is! ClosedWorldClassHierarchy) {
+    throw "Expected the class hierarchy to be ClosedWorldClassHierarchy "
+        "but it wasn't. It was ${classHierarchy.runtimeType}";
+  }
+  List<ForTestingClassInfo> classHierarchyData =
+      (classHierarchy as ClosedWorldClassHierarchy).getTestingClassInfo();
+  Map<Class, ForTestingClassInfo> classHierarchyMap =
+      new Map<Class, ForTestingClassInfo>();
+  for (ForTestingClassInfo info in classHierarchyData) {
+    if (classHierarchyMap[info.classNode] != null) {
+      throw "Two entries for ${info.classNode}";
+    }
+    classHierarchyMap[info.classNode] = info;
+  }
+
+  StringBuffer sb = new StringBuffer();
+  for (Library library in component.libraries) {
+    if (library.importUri.scheme == "dart") continue;
+    sb.writeln("Library ${library.importUri}");
+    for (Class c in library.classes) {
+      sb.writeln("  - Class ${c.name}");
+      ForTestingClassInfo info = classHierarchyMap[c];
+      if (info == null) {
+        throw "Didn't find any class hierarchy info for $c";
+      }
+      if (info.lazyDeclaredGettersAndCalls != null) {
+        sb.writeln("    - lazyDeclaredGettersAndCalls:");
+        for (Member member in info.lazyDeclaredGettersAndCalls) {
+          sb.writeln("      - ${member.name.name}");
+        }
+
+        // Expect these to be the same as in the class.
+        Set<Member> members = info.lazyDeclaredGettersAndCalls.toSet();
+        for (Field f in c.fields) {
+          if (f.isStatic) continue;
+          if (!f.hasImplicitGetter) continue;
+          if (!members.remove(f)) {
+            throw "Didn't find ${f.name.name} in lazyDeclaredGettersAndCalls "
+                "for ${c.name} in ${library.importUri}";
+          }
+        }
+        for (Procedure p in c.procedures) {
+          if (p.isStatic) continue;
+          if (p.isSetter) continue;
+          if (!members.remove(p)) {
+            throw "Didn't find ${p.name.name} in lazyDeclaredGettersAndCalls "
+                "for ${c.name} in ${library.importUri}";
+          }
+        }
+        if (members.isNotEmpty) {
+          throw "Still have ${members.map((m) => m.name.name)} left "
+              "for ${c.name} in ${library.importUri}";
+        }
+      }
+      if (info.lazyDeclaredSetters != null) {
+        sb.writeln("    - lazyDeclaredSetters:");
+        for (Member member in info.lazyDeclaredSetters) {
+          sb.writeln("      - ${member.name.name}");
+        }
+
+        // Expect these to be the same as in the class.
+        Set<Member> members = info.lazyDeclaredSetters.toSet();
+        for (Field f in c.fields) {
+          if (f.isStatic) continue;
+          if (!f.hasImplicitSetter) continue;
+          if (!members.remove(f)) {
+            throw "Didn't find $f in lazyDeclaredSetters for $c";
+          }
+        }
+        for (Procedure p in c.procedures) {
+          if (p.isStatic) continue;
+          if (!p.isSetter) continue;
+          if (!members.remove(p)) {
+            throw "Didn't find $p in lazyDeclaredSetters for $c";
+          }
+        }
+        if (members.isNotEmpty) {
+          throw "Still have ${members.map((m) => m.name.name)} left "
+              "for ${c.name} in ${library.importUri}";
+        }
+      }
+      if (info.lazyImplementedGettersAndCalls != null) {
+        sb.writeln("    - lazyImplementedGettersAndCalls:");
+        for (Member member in info.lazyImplementedGettersAndCalls) {
+          sb.writeln("      - ${member.name.name}");
+        }
+      }
+      if (info.lazyImplementedSetters != null) {
+        sb.writeln("    - lazyImplementedSetters:");
+        for (Member member in info.lazyImplementedSetters) {
+          sb.writeln("      - ${member.name.name}");
+        }
+      }
+      if (info.lazyInterfaceGettersAndCalls != null) {
+        sb.writeln("    - lazyInterfaceGettersAndCalls:");
+        for (Member member in info.lazyInterfaceGettersAndCalls) {
+          sb.writeln("      - ${member.name.name}");
+        }
+      }
+      if (info.lazyInterfaceSetters != null) {
+        sb.writeln("    - lazyInterfaceSetters:");
+        for (Member member in info.lazyInterfaceSetters) {
+          sb.writeln("      - ${member.name.name}");
+        }
+      }
+    }
+  }
+  if (checkExpectFile) {
+    String actualClassHierarchy = sb.toString();
+    Uri uri = data.loadedFrom.resolve(data.loadedFrom.pathSegments.last +
+        ".world.$worldNum.class_hierarchy.expect");
+    String expected;
+    File file = new File.fromUri(uri);
+    if (file.existsSync()) {
+      expected = file.readAsStringSync();
+    }
+    if (expected != actualClassHierarchy) {
+      if (context.updateExpectations) {
+        file.writeAsStringSync(actualClassHierarchy);
+      } else {
+        String extra = "";
+        if (expected == null) extra = "Expect file did not exist.\n";
+        throw "${extra}Unexpected serialized representation. "
+            "Fix or update $uri to contain the below:\n\n"
+            "$actualClassHierarchy";
+      }
+    }
+  }
+}
+
 void checkErrorsAndWarnings(
     Set<String> prevFormattedErrors,
     Set<String> formattedErrors,
@@ -899,14 +1045,14 @@ List<int> checkIncrementalSerialization(
       throw "Incremental serialization didn't remove any libraries!";
     }
     if (librariesAfter < librariesBefore && sink.builder.isEmpty) {
-      throw "Incremental serialization din't output any bytes, "
+      throw "Incremental serialization didn't output any bytes, "
           "but did remove libraries";
     } else if (librariesAfter == librariesBefore && !sink.builder.isEmpty) {
       throw "Incremental serialization did output bytes, "
           "but didn't remove libraries";
     }
     if (librariesAfter < librariesBefore) {
-      // If we actually did incremenally serialize anything, check the output!
+      // If we actually did incrementally serialize anything, check the output!
       BinaryPrinter printer = new BinaryPrinter(sink);
       printer.writeComponentFile(c);
       List<int> bytes = sink.builder.takeBytes();
@@ -1389,10 +1535,10 @@ class TestIncrementalCompiler extends IncrementalCompiler {
 void doSimulateTransformer(Component c) {
   for (Library lib in c.libraries) {
     if (lib.fields
-        .where((f) => f.name.name == "lalala_SimulateTransformer")
+        .where((f) => f.name.name == "unique_SimulateTransformer")
         .toList()
         .isNotEmpty) continue;
-    Name fieldName = new Name("lalala_SimulateTransformer");
+    Name fieldName = new Name("unique_SimulateTransformer");
     Field field = new Field(fieldName,
         isFinal: true,
         reference: lib.reference.canonicalName
@@ -1401,10 +1547,10 @@ void doSimulateTransformer(Component c) {
     lib.addMember(field);
     for (Class c in lib.classes) {
       if (c.fields
-          .where((f) => f.name.name == "lalala_SimulateTransformer")
+          .where((f) => f.name.name == "unique_SimulateTransformer")
           .toList()
           .isNotEmpty) continue;
-      fieldName = new Name("lalala_SimulateTransformer");
+      fieldName = new Name("unique_SimulateTransformer");
       field = new Field(fieldName,
           isFinal: true,
           reference: c.reference.canonicalName
diff --git a/pkg/front_end/test/spell_checking_list_tests.txt b/pkg/front_end/test/spell_checking_list_tests.txt
index 8a6399285c1..b2ce7b9e26a 100644
--- a/pkg/front_end/test/spell_checking_list_tests.txt
+++ b/pkg/front_end/test/spell_checking_list_tests.txt
@@ -57,6 +57,7 @@ boo
 bootstrap
 bots
 bowtie
+brand
 brave
 brown
 builddir
@@ -111,6 +112,7 @@ dartfile
 dashes
 day
 db
+debugger
 decrease
 decrements
 def
@@ -190,6 +192,7 @@ func
 futures
 gallery
 gamma
+gave
 gc
 gen
 generators
@@ -201,6 +204,7 @@ gulp
 gunk
 hackish
 harness
+helper2
 hest
 heuristics
 hi
@@ -276,6 +280,8 @@ moo
 mx
 mysdk
 negatable
+newest
+newworld
 ninja
 nonexisting
 noo
@@ -359,6 +365,8 @@ shipped
 shortest
 shot
 signalled
+slight
+smoke
 somehow
 spans
 spell
@@ -434,6 +442,7 @@ whitelist
 whitelisting
 wins
 workflow
+worlds
 ws
 x's
 xxx
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 a98a4f57fc4..16093f7856f 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
@@ -35,10 +35,10 @@ worlds:
     expectedContent:
       org-dartlang-test:///main.dart:
         - Procedure main
-        - Field lalala_SimulateTransformer
+        - Field unique_SimulateTransformer
       package:foo/foo.dart:
         - Field foo
-        - Field lalala_SimulateTransformer
+        - Field unique_SimulateTransformer
     neededDillLibraries:
       - package:foo/foo.dart
   - entry: main.dart
@@ -61,7 +61,7 @@ worlds:
     expectedContent:
       org-dartlang-test:///main.dart:
         - Procedure main
-        - Field lalala_SimulateTransformer
+        - Field unique_SimulateTransformer
       package:foo/foo.dart:
         - Field foo2
-        - Field lalala_SimulateTransformer
+        - Field unique_SimulateTransformer
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml.world.1.expect b/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml.world.1.expect
index 71e4ef19fa4..6ece7a5f766 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml.world.1.expect
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml.world.1.expect
@@ -2,13 +2,13 @@ main = <No Member>;
 library from "package:foo/foo.dart" as foo {
 
   static field dart.core::bool* foo = true;
-  final field dynamic lalala_SimulateTransformer /* from null */;
+  final field dynamic unique_SimulateTransformer /* from null */;
 }
 library from "org-dartlang-test:///main.dart" as main {
 
   import "package:foo/foo.dart";
 
-  final field dynamic lalala_SimulateTransformer /* from null */;
+  final field dynamic unique_SimulateTransformer /* from null */;
   static method main() → dynamic {
     dart.core::print(foo::foo);
   }
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml.world.2.expect b/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml.world.2.expect
index e13a156e841..90090ad4817 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml.world.2.expect
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/changing_modules_3.yaml.world.2.expect
@@ -2,13 +2,13 @@ main = <No Member>;
 library from "package:foo/foo.dart" as foo {
 
   static field dart.core::bool* foo2 = true;
-  final field dynamic lalala_SimulateTransformer /* from null */;
+  final field dynamic unique_SimulateTransformer /* from null */;
 }
 library from "org-dartlang-test:///main.dart" as main {
 
   import "package:foo/foo.dart";
 
-  final field dynamic lalala_SimulateTransformer /* from null */;
+  final field dynamic unique_SimulateTransformer /* from null */;
   static method main() → dynamic {
     dart.core::print(foo::foo2);
   }
diff --git a/pkg/front_end/testcases/incremental_initialize_from_dill/status.status b/pkg/front_end/testcases/incremental_initialize_from_dill/status.status
index a7bcd3bf061..9ac8e039d50 100644
--- a/pkg/front_end/testcases/incremental_initialize_from_dill/status.status
+++ b/pkg/front_end/testcases/incremental_initialize_from_dill/status.status
@@ -4,6 +4,9 @@
 
 # Status file for the test suite ../test/incremental_load_from_dill_test.dart.
 
+ffi_01: Crash # Class hierarchy is out of date.
+ffi_02: Crash # Class hierarchy is out of date.
+
 no_outline_change_1: Crash # Doesn't work on DillLibraryBuilders.
 no_outline_change_2: Crash # Doesn't work on DillLibraryBuilders.
 no_outline_change_6: Crash # Doesn't work on DillLibraryBuilders.
diff --git a/pkg/front_end/testing.json b/pkg/front_end/testing.json
index afa117c9143..5032126645b 100644
--- a/pkg/front_end/testing.json
+++ b/pkg/front_end/testing.json
@@ -284,8 +284,6 @@
         "test/fasta/super_mixins_test\\.dart$",
         "test/fasta/types/subtypes_benchmark\\.dart$",
         "test/fasta/unlinked_scope_test\\.dart$",
-        "test/incremental_load_from_dill_suite\\.dart$",
-        "test/incremental_load_from_invalid_dill_test\\.dart$",
         "test/memory_file_system_test\\.dart$",
         "test/scanner_fasta_test\\.dart$",
         "test/scanner_test\\.dart$",
diff --git a/pkg/kernel/lib/class_hierarchy.dart b/pkg/kernel/lib/class_hierarchy.dart
index 977cd45c34c..61e8b79bb15 100644
--- a/pkg/kernel/lib/class_hierarchy.dart
+++ b/pkg/kernel/lib/class_hierarchy.dart
@@ -451,6 +451,14 @@ class ClosedWorldClassHierarchy implements ClassHierarchy {
   final Map<Class, _ClassInfo> _infoMap =
       new LinkedHashMap<Class, _ClassInfo>();
 
+  List<ForTestingClassInfo> getTestingClassInfo() {
+    List<ForTestingClassInfo> result = new List<ForTestingClassInfo>();
+    for (_ClassInfo info in _infoMap.values) {
+      result.add(new ForTestingClassInfo._(info));
+    }
+    return result;
+  }
+
   _ClassInfo infoFor(Class c) {
     _ClassInfo info = _infoMap[c];
     info?.used = true;
@@ -1444,6 +1452,25 @@ int _intervalListSize(Uint32List intervalList) {
   return size;
 }
 
+class ForTestingClassInfo {
+  final Class classNode;
+  final List<Member> lazyDeclaredGettersAndCalls;
+  final List<Member> lazyDeclaredSetters;
+  final List<Member> lazyImplementedGettersAndCalls;
+  final List<Member> lazyImplementedSetters;
+  final List<Member> lazyInterfaceGettersAndCalls;
+  final List<Member> lazyInterfaceSetters;
+
+  ForTestingClassInfo._(_ClassInfo c)
+      : classNode = c.classNode,
+        lazyDeclaredGettersAndCalls = c.lazyDeclaredGettersAndCalls,
+        lazyDeclaredSetters = c.lazyDeclaredSetters,
+        lazyImplementedGettersAndCalls = c.lazyImplementedGettersAndCalls,
+        lazyImplementedSetters = c.lazyImplementedSetters,
+        lazyInterfaceGettersAndCalls = c.lazyInterfaceGettersAndCalls,
+        lazyInterfaceSetters = c.lazyInterfaceSetters;
+}
+
 class _ClassInfo {
   bool used = false;
   final Class classNode;