Migrate pkg/vm to null safety, part 3

TEST=ci

Issue: dart-lang/sdk#46620
Change-Id: I1ab793eec6ffd7e01cee1e6641138e96a4f4d9fc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/207864
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>

Author: alexmarkov

pkg/vm/lib/transformations/type_flow/analysis.dart

@@ -2,10 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.9
-
 /// Declares classes which describe a call: selectors and arguments.
-library vm.transformations.type_flow.calls;
 
 import 'dart:core' hide Type;
 
@@ -30,10 +27,10 @@ abstract class Selector {
   Selector(this.callKind);
 
   /// Interface or concrete target, may be null.
-  Member get member;
+  Member? get member;
 
   /// Selector name.
-  Name get name => member.name;
+  Name get name => member!.name;
 
   bool get isSetter => (callKind == CallKind.PropertySet);
 
@@ -46,6 +43,7 @@ abstract class Selector {
 
   /// Static approximation of Dart return type.
   DartType get staticReturnType {
+    final member = this.member;
     if (member == null) {
       return const DynamicType();
     }
@@ -61,7 +59,6 @@ abstract class Selector {
       case CallKind.SetFieldInConstructor:
         return const NeverType.nonNullable();
     }
-    return null;
   }
 
   bool memberAgreesToCallKind(Member member) {
@@ -79,7 +76,6 @@ abstract class Selector {
       case CallKind.SetFieldInConstructor:
         return member is Field;
     }
-    return false;
   }
 
   String get _callKindPrefix {
@@ -94,7 +90,6 @@ abstract class Selector {
       case CallKind.FieldInitializer:
         return 'init ';
     }
-    return '';
   }
 }
 
@@ -169,7 +164,7 @@ class DynamicSelector extends Selector {
   DynamicSelector(CallKind callKind, this.name) : super(callKind);
 
   @override
-  Member get member => null;
+  Member? get member => null;
 
   @override
   int get hashCode => (super.hashCode ^ name.hashCode + 37) & kHashMask;
@@ -189,7 +184,8 @@ class Args<T extends TypeExpr> {
   final List<T> values;
   final List<String> names;
 
-  int _hashCode;
+  @override
+  late final int hashCode = _computeHashCode();
 
   Args(this.values, {this.names = const <String>[]}) {
     assert(isSorted(names));
@@ -206,9 +202,6 @@ class Args<T extends TypeExpr> {
 
   T get receiver => values[0];
 
-  @override
-  int get hashCode => _hashCode ??= _computeHashCode();
-
   int _computeHashCode() {
     int hash = 1231;
     for (var v in values) {

pkg/vm/lib/transformations/type_flow/calls.dart

@@ -2,10 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.9
-
 /// Handling of native code and entry points.
-library vm.transformations.type_flow.native_code;
 
 import 'dart:core' hide Type;
 
@@ -35,24 +32,21 @@ abstract class EntryPointsListener {
   /// Record the fact that given member is called from this.
   void recordMemberCalledViaThis(Member target);
 
-  /// Record the fact that given method is torn off.
-  void recordTearOff(Procedure target) {}
+  /// Record the fact that given member is torn off.
+  void recordTearOff(Member target) {}
 }
 
 class PragmaEntryPointsVisitor extends RecursiveVisitor {
   final EntryPointsListener entryPoints;
   final NativeCodeOracle nativeCodeOracle;
   final PragmaAnnotationParser matcher;
-  Class currentClass = null;
 
   PragmaEntryPointsVisitor(
-      this.entryPoints, this.nativeCodeOracle, this.matcher) {
-    assert(matcher != null);
-  }
+      this.entryPoints, this.nativeCodeOracle, this.matcher);
 
-  PragmaEntryPointType _annotationsDefineRoot(List<Expression> annotations) {
+  PragmaEntryPointType? _annotationsDefineRoot(List<Expression> annotations) {
     for (var annotation in annotations) {
-      ParsedPragma pragma = matcher.parsePragma(annotation);
+      ParsedPragma? pragma = matcher.parsePragma(annotation);
       if (pragma == null) continue;
       if (pragma is ParsedEntryPointPragma) return pragma.type;
     }
@@ -72,7 +66,6 @@ class PragmaEntryPointsVisitor extends RecursiveVisitor {
       }
       nativeCodeOracle.addClassReferencedFromNativeCode(klass);
     }
-    currentClass = klass;
     klass.visitChildren(this);
   }
 
@@ -88,8 +81,7 @@ class PragmaEntryPointsVisitor extends RecursiveVisitor {
       }
       Member target = proc;
       while (target is Procedure && target.isRedirectingFactory) {
-        target = getRedirectingFactoryBody(target).target;
-        assert(target != null);
+        target = getRedirectingFactoryBody(target)!.target!;
         assert(
             (target is Procedure && target.isFactory) || target is Constructor);
       }
@@ -152,7 +144,7 @@ class PragmaEntryPointsVisitor extends RecursiveVisitor {
       }
       entryPoints
           .addRawCall(new DirectSelector(ctor, callKind: CallKind.Method));
-      entryPoints.addAllocatedClass(currentClass);
+      entryPoints.addAllocatedClass(ctor.enclosingClass);
       nativeCodeOracle.setMemberReferencedFromNativeCode(ctor);
     }
   }
@@ -201,9 +193,7 @@ class NativeCodeOracle {
   final Set<Class> _classesReferencedFromNativeCode = new Set<Class>();
   final PragmaAnnotationParser _matcher;
 
-  NativeCodeOracle(this._libraryIndex, this._matcher) {
-    assert(_matcher != null);
-  }
+  NativeCodeOracle(this._libraryIndex, this._matcher);
 
   void addClassReferencedFromNativeCode(Class klass) {
     _classesReferencedFromNativeCode.add(klass);
@@ -219,25 +209,26 @@ class NativeCodeOracle {
   bool isMemberReferencedFromNativeCode(Member member) =>
       _membersReferencedFromNativeCode.contains(member);
 
-  PragmaRecognizedType recognizedType(Member member) {
+  PragmaRecognizedType? recognizedType(Member member) {
     for (var annotation in member.annotations) {
-      ParsedPragma pragma = _matcher.parsePragma(annotation);
+      ParsedPragma? pragma = _matcher.parsePragma(annotation);
       if (pragma is ParsedRecognized) {
         return pragma.type;
       }
     }
     return null;
   }
 
-  bool isRecognized(Member member, [List<PragmaRecognizedType> expectedTypes]) {
-    PragmaRecognizedType type = recognizedType(member);
+  bool isRecognized(Member member,
+      [List<PragmaRecognizedType>? expectedTypes]) {
+    PragmaRecognizedType? type = recognizedType(member);
     return type != null &&
         (expectedTypes == null || expectedTypes.contains(type));
   }
 
   bool hasDisableUnboxedParameters(Member member) {
     for (var annotation in member.annotations) {
-      ParsedPragma pragma = _matcher.parsePragma(annotation);
+      ParsedPragma? pragma = _matcher.parsePragma(annotation);
       if (pragma is ParsedDisableUnboxedParameters) {
         if (member.enclosingLibrary.importUri.scheme != "dart") {
           throw "ERROR: Cannot use @pragma(vm:disable-unboxed-parameters) outside core libraries.";
@@ -255,11 +246,11 @@ class NativeCodeOracle {
       EntryPointsListener entryPointsListener,
       TypesBuilder typesBuilder,
       RuntimeTypeTranslator translator) {
-    TypeExpr returnType = null;
-    bool nullable = null;
+    TypeExpr? returnType = null;
+    bool? nullable = null;
 
     for (var annotation in member.annotations) {
-      ParsedPragma pragma = _matcher.parsePragma(annotation);
+      ParsedPragma? pragma = _matcher.parsePragma(annotation);
       if (pragma == null) continue;
       if (pragma is ParsedResultTypeByTypePragma ||
           pragma is ParsedResultTypeByPathPragma ||
@@ -278,8 +269,8 @@ class NativeCodeOracle {
           returnType = entryPointsListener.addAllocatedClass(type.classNode);
           if (pragma.resultTypeUsesPassedTypeArguments) {
             returnType = translator.instantiateConcreteType(
-                returnType,
-                member.function.typeParameters
+                returnType as ConcreteType,
+                member.function!.typeParameters
                     .map((t) => TypeParameterType(
                         t, TypeParameterType.computeNullabilityFromBound(t)))
                     .toList());
@@ -314,7 +305,7 @@ class NativeCodeOracle {
       return returnType;
     } else {
       return typesBuilder.fromStaticType(
-          member.function.returnType, nullable ?? true);
+          member.function!.returnType, nullable ?? true);
     }
   }
 }

pkg/vm/lib/transformations/type_flow/native_code.dart

@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.9
-
 import 'package:kernel/ast.dart';
 import 'package:kernel/clone.dart' show CloneVisitorNotMembers;
 import 'package:kernel/core_types.dart' show CoreTypes;
@@ -47,14 +45,14 @@ class ProtobufHandler {
   final Procedure _builderInfoAddMethod;
 
   // Type of BuilderInfo.add<Null>().
-  FunctionType _typeOfBuilderInfoAddOfNull;
+  late FunctionType _typeOfBuilderInfoAddOfNull;
 
   final _messageClasses = <Class, _MessageClass>{};
   final _invalidatedClasses = <_MessageClass>{};
 
   /// Creates [ProtobufHandler] instance for [component].
   /// Returns null if protobuf library is not used.
-  static ProtobufHandler forComponent(
+  static ProtobufHandler? forComponent(
       Component component, CoreTypes coreTypes) {
     final libraryIndex = LibraryIndex(component, [protobufLibraryUri]);
     if (!libraryIndex.containsLibrary(protobufLibraryUri)) {
@@ -68,12 +66,12 @@ class ProtobufHandler {
             libraryIndex.getClass(protobufLibraryUri, 'GeneratedMessage'),
         _tagNumberClass =
             libraryIndex.getClass(protobufLibraryUri, 'TagNumber'),
-        _tagNumberField = libraryIndex.getMember(
-            protobufLibraryUri, 'TagNumber', 'tagNumber'),
+        _tagNumberField =
+            libraryIndex.getField(protobufLibraryUri, 'TagNumber', 'tagNumber'),
         _builderInfoClass =
             libraryIndex.getClass(protobufLibraryUri, 'BuilderInfo'),
-        _builderInfoAddMethod =
-            libraryIndex.getMember(protobufLibraryUri, 'BuilderInfo', 'add') {
+        _builderInfoAddMethod = libraryIndex.getProcedure(
+            protobufLibraryUri, 'BuilderInfo', 'add') {
     final functionType = _builderInfoAddMethod.getterType as FunctionType;
     _typeOfBuilderInfoAddOfNull = Substitution.fromPairs(
             functionType.typeParameters, const <DartType>[NullType()])
@@ -130,8 +128,9 @@ class ProtobufHandler {
   List<Field> getInvalidatedFields() {
     final fields = <Field>[];
     for (var cls in _invalidatedClasses) {
-      if (cls._metadataField != null) {
-        fields.add(cls._metadataField);
+      final field = cls._metadataField;
+      if (field != null) {
+        fields.add(field);
       }
     }
     _invalidatedClasses.clear();
@@ -143,14 +142,15 @@ class ProtobufHandler {
     ++Statistics.protobufMetadataInitializersUpdated;
     Statistics.protobufMetadataFieldsPruned -= cls.numberOfFieldsPruned;
 
-    final field = cls._metadataField;
-    if (cls._originalInitializer == null) {
-      cls._originalInitializer = field.initializer;
+    final field = cls._metadataField!;
+    Expression? originalInitializer = cls._originalInitializer;
+    if (originalInitializer == null) {
+      cls._originalInitializer = originalInitializer = field.initializer!;
     }
     final cloner = CloneVisitorNotMembers();
-    field.initializer = cloner.clone(cls._originalInitializer)..parent = field;
+    field.initializer = cloner.clone(originalInitializer)..parent = field;
     final transformer = _MetadataTransformer(this, cls);
-    field.initializer.accept(transformer);
+    field.initializer!.accept(transformer);
     _invalidatedClasses.remove(cls);
 
     cls.numberOfFieldsPruned = transformer.numberOfFieldsPruned;
@@ -168,8 +168,8 @@ class ProtobufHandler {
 }
 
 class _MessageClass {
-  Field _metadataField;
-  Expression _originalInitializer;
+  Field? _metadataField;
+  Expression? _originalInitializer;
   final _usedTags = <int>{};
   int numberOfFieldsPruned = 0;
 }