diff --git a/pkg/compiler/lib/src/deferred_load/output_unit.dart b/pkg/compiler/lib/src/deferred_load/output_unit.dart
index 5d8345f0ee7..cea65c21618 100644
--- a/pkg/compiler/lib/src/deferred_load/output_unit.dart
+++ b/pkg/compiler/lib/src/deferred_load/output_unit.dart
@@ -10,7 +10,7 @@ import '../common.dart';
 import '../constants/values.dart'
     show ConstantValue, DeferredGlobalConstantValue;
 import '../elements/entities.dart';
-import '../serialization/serialization.dart';
+import '../serialization/serialization_interfaces.dart';
 import '../options.dart';
 
 // TODO(48820): Move OutputUnit and compareImportEntities back here.
diff --git a/pkg/compiler/lib/src/inferrer/engine.dart b/pkg/compiler/lib/src/inferrer/engine.dart
index d3aeab174e8..997d067aa61 100644
--- a/pkg/compiler/lib/src/inferrer/engine.dart
+++ b/pkg/compiler/lib/src/inferrer/engine.dart
@@ -24,7 +24,7 @@ import '../js_model/js_world.dart';
 import '../js_model/locals.dart';
 import '../native/behavior.dart';
 import '../options.dart';
-import '../serialization/serialization.dart';
+import '../serialization/serialization_interfaces.dart';
 import '../universe/call_structure.dart';
 import '../universe/selector.dart';
 import '../universe/side_effects.dart';
diff --git a/pkg/compiler/lib/src/inferrer/powersets/powersets.dart b/pkg/compiler/lib/src/inferrer/powersets/powersets.dart
index 998b848ce23..b2fea8e3013 100644
--- a/pkg/compiler/lib/src/inferrer/powersets/powersets.dart
+++ b/pkg/compiler/lib/src/inferrer/powersets/powersets.dart
@@ -9,7 +9,7 @@ import '../../elements/entities.dart';
 import '../../elements/names.dart';
 import '../../elements/types.dart' show DartType;
 import '../../ir/class_relation.dart';
-import '../../serialization/serialization.dart';
+import '../../serialization/serialization_interfaces.dart';
 import '../../universe/selector.dart';
 import '../../universe/world_builder.dart';
 import '../../universe/use.dart';
diff --git a/pkg/compiler/lib/src/inferrer/typemasks/masks.dart b/pkg/compiler/lib/src/inferrer/typemasks/masks.dart
index cdccaa4dfe5..da421b973f6 100644
--- a/pkg/compiler/lib/src/inferrer/typemasks/masks.dart
+++ b/pkg/compiler/lib/src/inferrer/typemasks/masks.dart
@@ -15,7 +15,7 @@ import '../../elements/entities.dart';
 import '../../elements/names.dart';
 import '../../elements/types.dart';
 import '../../ir/class_relation.dart';
-import '../../serialization/serialization.dart';
+import '../../serialization/serialization_interfaces.dart';
 import '../../universe/class_hierarchy.dart';
 import '../../universe/selector.dart' show Selector;
 import '../../universe/use.dart' show DynamicUse;
diff --git a/pkg/compiler/lib/src/inferrer/wrapped.dart b/pkg/compiler/lib/src/inferrer/wrapped.dart
index 21717cb022e..21a747318c7 100644
--- a/pkg/compiler/lib/src/inferrer/wrapped.dart
+++ b/pkg/compiler/lib/src/inferrer/wrapped.dart
@@ -9,7 +9,7 @@ import '../elements/entities.dart';
 import '../elements/names.dart';
 import '../elements/types.dart' show DartType;
 import '../ir/class_relation.dart';
-import '../serialization/serialization.dart';
+import '../serialization/serialization_interfaces.dart';
 import '../universe/selector.dart';
 import '../universe/world_builder.dart';
 import '../universe/use.dart';
diff --git a/pkg/compiler/lib/src/js_backend/backend_usage.dart b/pkg/compiler/lib/src/js_backend/backend_usage.dart
index 37ef5340ad8..30138ebecc1 100644
--- a/pkg/compiler/lib/src/js_backend/backend_usage.dart
+++ b/pkg/compiler/lib/src/js_backend/backend_usage.dart
@@ -10,7 +10,7 @@ import '../elements/entities.dart';
 import '../elements/types.dart';
 import '../ir/runtime_type_analysis.dart';
 import '../kernel/kernel_strategy.dart';
-import '../serialization/serialization.dart';
+import '../serialization/serialization_interfaces.dart';
 import '../universe/feature.dart';
 import '../util/util.dart' show Setlet;
 import 'backend_impact.dart';
diff --git a/pkg/compiler/lib/src/js_backend/deferred_holder_expression.dart b/pkg/compiler/lib/src/js_backend/deferred_holder_expression.dart
index 2e24fe10779..dc85fab3503 100644
--- a/pkg/compiler/lib/src/js_backend/deferred_holder_expression.dart
+++ b/pkg/compiler/lib/src/js_backend/deferred_holder_expression.dart
@@ -10,7 +10,7 @@ import 'package:front_end/src/api_unstable/dart2js.dart' show $A;
 import '../common/elements.dart' show JCommonElements;
 import '../elements/entities.dart';
 import '../js/js.dart' as js;
-import '../serialization/serialization.dart';
+import '../serialization/serialization_interfaces.dart';
 import '../util/util.dart';
 import '../js_emitter/model.dart';
 import '../constants/values.dart' show ConstantValue;
diff --git a/pkg/compiler/lib/src/js_backend/field_analysis.dart b/pkg/compiler/lib/src/js_backend/field_analysis.dart
index 4076ead40fd..b22fb53f10c 100644
--- a/pkg/compiler/lib/src/js_backend/field_analysis.dart
+++ b/pkg/compiler/lib/src/js_backend/field_analysis.dart
@@ -14,13 +14,13 @@ import '../elements/entity_utils.dart';
 import '../elements/types.dart';
 import '../ir/scope_visitor.dart';
 import '../js_model/elements.dart' show JField;
-import '../js_model/js_world_builder.dart';
+import '../js_model/js_world_builder.dart' show JsToFrontendMap;
 import '../kernel/element_map.dart';
 import '../kernel/kernel_strategy.dart';
 import '../kernel/kelements.dart' show KClass, KField, KConstructor;
 import '../kernel/kernel_world.dart';
 import '../options.dart';
-import '../serialization/serialization.dart';
+import '../serialization/serialization_interfaces.dart';
 import '../universe/member_usage.dart';
 
 /// AllocatorAnalysis
diff --git a/pkg/compiler/lib/src/js_backend/inferred_data.dart b/pkg/compiler/lib/src/js_backend/inferred_data.dart
index 84a067a0571..6e96121c099 100644
--- a/pkg/compiler/lib/src/js_backend/inferred_data.dart
+++ b/pkg/compiler/lib/src/js_backend/inferred_data.dart
@@ -9,7 +9,7 @@ import 'dart:collection' show Queue;
 import '../common.dart';
 import '../elements/entities.dart';
 import '../inferrer/abstract_value_domain.dart';
-import '../serialization/serialization.dart';
+import '../serialization/serialization_interfaces.dart';
 import '../universe/selector.dart';
 import '../universe/side_effects.dart';
 import '../world.dart';
diff --git a/pkg/compiler/lib/src/js_backend/interceptor_data.dart b/pkg/compiler/lib/src/js_backend/interceptor_data.dart
index 299dd02122d..32cadd15594 100644
--- a/pkg/compiler/lib/src/js_backend/interceptor_data.dart
+++ b/pkg/compiler/lib/src/js_backend/interceptor_data.dart
@@ -13,7 +13,7 @@ import '../elements/entities.dart';
 import '../elements/types.dart';
 import '../inferrer/abstract_value_domain.dart';
 import '../js/js.dart' as jsAst;
-import '../serialization/serialization.dart';
+import '../serialization/serialization_interfaces.dart';
 import '../universe/class_set.dart';
 import '../universe/selector.dart';
 import '../world.dart' show JClosedWorld;
diff --git a/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart b/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
index 9b9cc0d3be4..c62f4a3d01e 100644
--- a/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
+++ b/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
@@ -10,7 +10,7 @@ import '../common/names.dart' show Identifiers, Selectors;
 import '../elements/entities.dart';
 import '../inferrer/types.dart';
 import '../kernel/no_such_method_resolver.dart';
-import '../serialization/serialization.dart';
+import '../serialization/serialization_interfaces.dart';
 
 /// [NoSuchMethodRegistry] and [NoSuchMethodData] categorizes `noSuchMethod`
 /// implementations.
diff --git a/pkg/compiler/lib/src/js_backend/runtime_types_resolution.dart b/pkg/compiler/lib/src/js_backend/runtime_types_resolution.dart
index 9791f4ad103..61c15b48c4f 100644
--- a/pkg/compiler/lib/src/js_backend/runtime_types_resolution.dart
+++ b/pkg/compiler/lib/src/js_backend/runtime_types_resolution.dart
@@ -16,7 +16,7 @@ import '../ir/runtime_type_analysis.dart';
 import '../kernel/kelements.dart';
 import '../kernel/kernel_world.dart';
 import '../options.dart';
-import '../serialization/serialization.dart';
+import '../serialization/serialization_interfaces.dart';
 import '../universe/class_hierarchy.dart';
 import '../universe/class_set.dart';
 import '../universe/feature.dart';
diff --git a/pkg/compiler/lib/src/serialization/serialization_interfaces.dart b/pkg/compiler/lib/src/serialization/serialization_interfaces.dart
index c893ffdb1b4..5c2e61bc9ef 100644
--- a/pkg/compiler/lib/src/serialization/serialization_interfaces.dart
+++ b/pkg/compiler/lib/src/serialization/serialization_interfaces.dart
@@ -7,6 +7,7 @@ import 'package:kernel/ast.dart' as ir show DartType, Member, TreeNode;
 import '../constants/values.dart' show ConstantValue;
 import '../elements/entities.dart';
 import '../elements/types.dart' show DartType;
+import '../inferrer/abstract_value_domain.dart' show AbstractValue;
 
 export 'tags.dart';
 
@@ -61,9 +62,17 @@ abstract class DataSinkWriter {
 
   void writeClass(covariant ClassEntity value); // IndexedClass
   void writeClassOrNull(covariant ClassEntity? value); // IndexedClass
+  void writeClasses(Iterable<ClassEntity> values, {bool allowNull = false});
+  void writeClassMap<V>(Map<ClassEntity, V>? map, void f(V value),
+      {bool allowNull = false});
+
   void writeTypeVariable(
       covariant TypeVariableEntity value); // IndexedTypeVariable
 
+  void writeMember(covariant MemberEntity member); // IndexMember
+  void writeMemberOrNull(covariant MemberEntity? member); // IndexMember
+  void writeMembers(Iterable<MemberEntity>? values, {bool allowNull = false});
+
   void writeMemberMap<V>(
       Map<MemberEntity, V>? map, void f(MemberEntity member, V value),
       {bool allowNull = false});
@@ -89,6 +98,19 @@ abstract class DataSinkWriter {
       {bool allowNull = false});
 
   void writeConstant(ConstantValue value);
+  void writeConstantOrNull(ConstantValue? value);
+  void writeConstantMap<V>(Map<ConstantValue, V>? map, void f(V value),
+      {bool allowNull = false});
+
+  void writeValueOrNull<E>(E? value, void f(E value));
+
+  void writeImport(ImportEntity import);
+  void writeImportOrNull(ImportEntity? import);
+  void writeImports(Iterable<ImportEntity>? values, {bool allowNull = false});
+  void writeImportMap<V>(Map<ImportEntity, V>? map, void f(V value),
+      {bool allowNull = false});
+
+  void writeAbstractValue(AbstractValue value);
 }
 
 /// Migrated interface for methods of DataSourceReader.
@@ -112,8 +134,17 @@ abstract class DataSourceReader {
 
   ClassEntity readClass(); // IndexedClass
   ClassEntity? readClassOrNull(); // IndexedClass
+  List<E> readClasses<E extends ClassEntity>();
+  List<E>? readClassesOrNull<E extends ClassEntity>();
+  Map<K, V> readClassMap<K extends ClassEntity, V>(V f());
+  Map<K, V>? readClassMapOrNull<K extends ClassEntity, V>(V f());
+
   TypeVariableEntity readTypeVariable(); // IndexedTypeVariable
 
+  MemberEntity readMember();
+  MemberEntity? readMemberOrNull();
+  List<E> readMembers<E extends MemberEntity>();
+  List<E>? readMembersOrNull<E extends MemberEntity>();
   Map<K, V> readMemberMap<K extends MemberEntity, V>(V f(MemberEntity member));
   Map<K, V>? readMemberMapOrNull<K extends MemberEntity, V>(
       V f(MemberEntity member));
@@ -140,6 +171,20 @@ abstract class DataSourceReader {
   List<E>? readListOrNull<E extends Object>(E f());
 
   ConstantValue readConstant();
+  ConstantValue? readConstantOrNull();
+  Map<K, V> readConstantMap<K extends ConstantValue, V>(V f());
+  Map<K, V>? readConstantMapOrNull<K extends ConstantValue, V>(V f());
+
+  E? readValueOrNull<E>(E f());
+
+  ImportEntity readImport();
+  ImportEntity? readImportOrNull();
+  List<ImportEntity> readImports();
+  List<ImportEntity>? readImportsOrNull();
+  Map<ImportEntity, V> readImportMap<V>(V f());
+  Map<ImportEntity, V>? readImportMapOrNull<V>(V f());
+
+  AbstractValue readAbstractValue();
 
   E readWithSource<E>(DataSourceReader source, E f());
   E readWithOffset<E>(int offset, E f());
diff --git a/pkg/compiler/lib/src/serialization/sink.dart b/pkg/compiler/lib/src/serialization/sink.dart
index 4f1231eedb9..0d3bef61801 100644
--- a/pkg/compiler/lib/src/serialization/sink.dart
+++ b/pkg/compiler/lib/src/serialization/sink.dart
@@ -151,6 +151,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   ///
   /// This is a convenience method to be used together with
   /// [DataSourceReader.readValueOrNull].
+  @override
   void writeValueOrNull<E>(E value, void f(E value)) {
     writeBool(value != null);
     if (value != null) {
@@ -766,6 +767,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   ///
   /// This is a convenience method to be used together with
   /// [DataSourceReader.readClasses].
+  @override
   void writeClasses(Iterable<ClassEntity> values, {bool allowNull = false}) {
     if (values == null) {
       assert(allowNull);
@@ -784,6 +786,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   ///
   /// This is a convenience method to be used together with
   /// [DataSourceReader.readClassMap].
+  @override
   void writeClassMap<V>(Map<ClassEntity, V> map, void f(V value),
       {bool allowNull = false}) {
     if (map == null) {
@@ -799,6 +802,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   }
 
   /// Writes a reference to the indexed member [value] to this data sink.
+  @override
   void writeMember(IndexedMember value) {
     _entityWriter.writeMemberToDataSink(this, value);
   }
@@ -808,6 +812,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   ///
   /// This is a convenience method to be used together with
   /// [DataSourceReader.readMemberOrNull].
+  @override
   void writeMemberOrNull(IndexedMember value) {
     writeBool(value != null);
     if (value != null) {
@@ -820,6 +825,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   ///
   /// This is a convenience method to be used together with
   /// [DataSourceReader.readMembers].
+  @override
   void writeMembers(Iterable<MemberEntity> values, {bool allowNull = false}) {
     if (values == null) {
       assert(allowNull);
@@ -1048,6 +1054,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   }
 
   /// Writes the potentially `null` constant [value] to this data sink.
+  @override
   void writeConstantOrNull(ConstantValue value) {
     writeBool(value != null);
     if (value != null) {
@@ -1079,6 +1086,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   ///
   /// This is a convenience method to be used together with
   /// [DataSourceReader.readConstantMap].
+  @override
   void writeConstantMap<V>(Map<ConstantValue, V> map, void f(V value),
       {bool allowNull = false}) {
     if (map == null) {
@@ -1122,6 +1130,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   }
 
   /// Writes the import [value] to this data sink.
+  @override
   void writeImport(ImportEntity value) {
     _writeDataKind(DataKind.import);
     _writeImport(value);
@@ -1140,6 +1149,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   }
 
   /// Writes the potentially `null` import [value] to this data sink.
+  @override
   void writeImportOrNull(ImportEntity value) {
     writeBool(value != null);
     if (value != null) {
@@ -1152,6 +1162,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   ///
   /// This is a convenience method to be used together with
   /// [DataSourceReader.readImports].
+  @override
   void writeImports(Iterable<ImportEntity> values, {bool allowNull = false}) {
     if (values == null) {
       assert(allowNull);
@@ -1170,7 +1181,8 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   ///
   /// This is a convenience method to be used together with
   /// [DataSourceReader.readImportMap].
-  void writeImportMap<V>(Map<ImportEntity, V> map, void f(V value),
+  @override
+  void writeImportMap<V>(Map<ImportEntity, V> /*?*/ map, void f(V value),
       {bool allowNull = false}) {
     if (map == null) {
       assert(allowNull);
@@ -1187,6 +1199,7 @@ class DataSinkWriter implements migrated.DataSinkWriter {
   /// Writes an abstract [value] to this data sink.
   ///
   /// This feature is only available a [CodegenWriter] has been registered.
+  @override
   void writeAbstractValue(AbstractValue value) {
     assert(_codegenWriter != null,
         "Can not serialize an AbstractValue without a registered codegen writer.");
diff --git a/pkg/compiler/lib/src/serialization/source.dart b/pkg/compiler/lib/src/serialization/source.dart
index 879c4a35972..6136b59df76 100644
--- a/pkg/compiler/lib/src/serialization/source.dart
+++ b/pkg/compiler/lib/src/serialization/source.dart
@@ -273,6 +273,7 @@ class DataSourceReader implements migrated.DataSourceReader {
   ///
   /// This is a convenience method to be used together with
   /// [DataSinkWriter.writeValueOrNull].
+  @override
   E readValueOrNull<E>(E f()) {
     bool hasValue = readBool();
     if (hasValue) {
@@ -982,13 +983,23 @@ class DataSourceReader implements migrated.DataSourceReader {
   }
 
   /// Reads a list of references to indexed classes from this data source.
-  /// If [emptyAsNull] is `true`, `null` is returned instead of an empty list.
   ///
   /// This is a convenience method to be used together with
   /// [DataSinkWriter.writeClasses].
-  List<E> readClasses<E extends ClassEntity>({bool emptyAsNull = false}) {
+  @override
+  List<E> readClasses<E extends ClassEntity>() {
+    return readClassesOrNull<E>() ?? List.empty();
+  }
+
+  /// Reads a list of references to indexed classes from this data source.
+  /// `null` is returned instead of an empty list.
+  ///
+  /// This is a convenience method to be used together with
+  /// [DataSinkWriter.writeClasses].
+  @override
+  List<E> readClassesOrNull<E extends ClassEntity>() {
     int count = readInt();
-    if (count == 0 && emptyAsNull) return null;
+    if (count == 0) return null;
     List<E> list = List<E>.filled(count, null);
     for (int i = 0; i < count; i++) {
       ClassEntity cls = readClass();
@@ -998,15 +1009,25 @@ class DataSourceReader implements migrated.DataSourceReader {
   }
 
   /// Reads a map from indexed classes to [V] values from this data source,
-  /// calling [f] to read each value from the data source. If [emptyAsNull] is
-  /// `true`, `null` is returned instead of an empty map.
+  /// calling [f] to read each value from the data source.
   ///
   /// This is a convenience method to be used together with
   /// [DataSinkWriter.writeClassMap].
-  Map<K, V> readClassMap<K extends ClassEntity, V>(V f(),
-      {bool emptyAsNull = false}) {
+  @override
+  Map<K, V> readClassMap<K extends ClassEntity, V>(V f()) {
+    return readClassMapOrNull<K, V>(f) ?? {};
+  }
+
+  /// Reads a map from indexed classes to [V] values from this data source,
+  /// calling [f] to read each value from the data source. `null` is returned if
+  /// the map is empty.
+  ///
+  /// This is a convenience method to be used together with
+  /// [DataSinkWriter.writeClassMap].
+  @override
+  Map<K, V> /*?*/ readClassMapOrNull<K extends ClassEntity, V>(V f()) {
     int count = readInt();
-    if (count == 0 && emptyAsNull) return null;
+    if (count == 0) return null;
     Map<K, V> map = {};
     for (int i = 0; i < count; i++) {
       ClassEntity cls = readClass();
@@ -1017,12 +1038,14 @@ class DataSourceReader implements migrated.DataSourceReader {
   }
 
   /// Reads a reference to an indexed member from this data source.
+  @override
   IndexedMember /*!*/ readMember() {
     return _entityReader.readMemberFromDataSource(this, entityLookup);
   }
 
   /// Reads a reference to a potentially `null` indexed member from this data
   /// source.
+  @override
   IndexedMember readMemberOrNull() {
     bool hasValue = readBool();
     if (hasValue) {
@@ -1035,6 +1058,7 @@ class DataSourceReader implements migrated.DataSourceReader {
   ///
   /// This is a convenience method to be used together with
   /// [DataSinkWriter.writeMembers].
+  @override
   List<E /*!*/ > readMembers<E extends MemberEntity /*!*/ >() {
     return readMembersOrNull() ?? List.empty();
   }
@@ -1044,6 +1068,7 @@ class DataSourceReader implements migrated.DataSourceReader {
   ///
   /// This is a convenience method to be used together with
   /// [DataSinkWriter.writeMembers].
+  @override
   List<E /*!*/ > readMembersOrNull<E extends MemberEntity /*!*/ >() {
     int count = readInt();
     if (count == 0) return null;
@@ -1263,6 +1288,7 @@ class DataSourceReader implements migrated.DataSourceReader {
   }
 
   /// Reads a potentially `null` constant value from this data source.
+  @override
   ConstantValue readConstantOrNull() {
     bool hasClass = readBool();
     if (hasClass) {
@@ -1288,15 +1314,25 @@ class DataSourceReader implements migrated.DataSourceReader {
   }
 
   /// Reads a map from constant values to [V] values from this data source,
-  /// calling [f] to read each value from the data source. If [emptyAsNull] is
-  /// `true`, `null` is returned instead of an empty map.
+  /// calling [f] to read each value from the data source.
   ///
   /// This is a convenience method to be used together with
   /// [DataSinkWriter.writeConstantMap].
-  Map<K, V> readConstantMap<K extends ConstantValue, V>(V f(),
-      {bool emptyAsNull = false}) {
+  @override
+  Map<K, V> readConstantMap<K extends ConstantValue, V>(V f()) {
+    return readConstantMapOrNull<K, V>(f) ?? {};
+  }
+
+  /// Reads a map from constant values to [V] values from this data source,
+  /// calling [f] to read each value from the data source. `null` is returned
+  /// instead of an empty map.
+  ///
+  /// This is a convenience method to be used together with
+  /// [DataSinkWriter.writeConstantMap].
+  @override
+  Map<K, V> /*?*/ readConstantMapOrNull<K extends ConstantValue, V>(V f()) {
     int count = readInt();
-    if (count == 0 && emptyAsNull) return null;
+    if (count == 0) return null;
     Map<K, V> map = {};
     for (int i = 0; i < count; i++) {
       ConstantValue key = readConstant();
@@ -1334,6 +1370,7 @@ class DataSourceReader implements migrated.DataSourceReader {
     return BigInt.parse(readString());
   }
 
+  @override
   ImportEntity readImport() {
     _checkDataKind(DataKind.import);
     return _readImport();
@@ -1353,6 +1390,7 @@ class DataSourceReader implements migrated.DataSourceReader {
   }
 
   /// Reads a potentially `null` import from this data source.
+  @override
   ImportEntity readImportOrNull() {
     bool hasClass = readBool();
     if (hasClass) {
@@ -1361,14 +1399,24 @@ class DataSourceReader implements migrated.DataSourceReader {
     return null;
   }
 
-  /// Reads a list of imports from this data source. If [emptyAsNull] is
-  /// `true`, `null` is returned instead of an empty list.
+  /// Reads a list of imports from this data source.
   ///
   /// This is a convenience method to be used together with
   /// [DataSinkWriter.writeImports].
-  List<ImportEntity> readImports({bool emptyAsNull = false}) {
+  @override
+  List<ImportEntity> readImports() {
+    return readImportsOrNull() ?? const [];
+  }
+
+  /// Reads a list of imports from this data source.
+  /// `null` is returned instead of an empty list.
+  ///
+  /// This is a convenience method to be used together with
+  /// [DataSinkWriter.writeImports].
+  @override
+  List<ImportEntity> /*?*/ readImportsOrNull() {
     int count = readInt();
-    if (count == 0 && emptyAsNull) return null;
+    if (count == 0) return null;
     List<ImportEntity> list = List<ImportEntity>.filled(count, null);
     for (int i = 0; i < count; i++) {
       list[i] = readImport();
@@ -1377,14 +1425,25 @@ class DataSourceReader implements migrated.DataSourceReader {
   }
 
   /// Reads a map from imports to [V] values from this data source,
-  /// calling [f] to read each value from the data source. If [emptyAsNull] is
-  /// `true`, `null` is returned instead of an empty map.
+  /// calling [f] to read each value from the data source.
   ///
   /// This is a convenience method to be used together with
   /// [DataSinkWriter.writeImportMap].
-  Map<ImportEntity, V> readImportMap<V>(V f(), {bool emptyAsNull = false}) {
+  @override
+  Map<ImportEntity, V> readImportMap<V>(V f()) {
+    return readImportMapOrNull<V>(f) ?? {};
+  }
+
+  /// Reads a map from imports to [V] values from this data source, calling [f]
+  /// to read each value from the data source. `null` is returned if the map is
+  /// empty map.
+  ///
+  /// This is a convenience method to be used together with
+  /// [DataSinkWriter.writeImportMap].
+  @override
+  Map<ImportEntity, V> /*?*/ readImportMapOrNull<V>(V f()) {
     int count = readInt();
-    if (count == 0 && emptyAsNull) return null;
+    if (count == 0) return null;
     Map<ImportEntity, V> map = {};
     for (int i = 0; i < count; i++) {
       ImportEntity key = readImport();
@@ -1397,6 +1456,7 @@ class DataSourceReader implements migrated.DataSourceReader {
   /// Reads an [AbstractValue] from this data source.
   ///
   /// This feature is only available a [CodegenReader] has been registered.
+  @override
   AbstractValue readAbstractValue() {
     assert(
         _codegenReader != null,
diff --git a/pkg/compiler/lib/src/universe/member_usage.dart b/pkg/compiler/lib/src/universe/member_usage.dart
index 21027d0bb2e..9bb2a33038a 100644
--- a/pkg/compiler/lib/src/universe/member_usage.dart
+++ b/pkg/compiler/lib/src/universe/member_usage.dart
@@ -9,7 +9,7 @@ import 'dart:math' as Math;
 import '../common.dart';
 import '../constants/values.dart';
 import '../elements/entities.dart';
-import '../js_model/closure.dart';
+import '../js_model/closure.dart' show JRecordField;
 import '../serialization/serialization_interfaces.dart';
 import '../util/enumset.dart';
 import 'call_structure.dart';
diff --git a/pkg/compiler/lib/src/universe/use.dart b/pkg/compiler/lib/src/universe/use.dart
index 2adead406b2..28fdeed91c0 100644
--- a/pkg/compiler/lib/src/universe/use.dart
+++ b/pkg/compiler/lib/src/universe/use.dart
@@ -23,8 +23,8 @@ import '../constants/values.dart';
 import '../elements/types.dart';
 import '../elements/entities.dart';
 import '../inferrer/abstract_value_domain.dart';
-import '../serialization/serialization.dart';
-import '../js_model/closure.dart';
+import '../serialization/serialization_interfaces.dart';
+import '../js_model/closure.dart' show JRecordField;
 import '../util/util.dart' show equalElements, Hashing;
 import 'call_structure.dart' show CallStructure;
 import 'selector.dart' show Selector;