Remove Compiler access from ResolutionEnqueuer

pkg/compiler/lib/src/enqueue.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 library dart2js.enqueue;
 
 import 'dart:collection' show Queue;
 
+import 'cache_strategy.dart';
+import 'common/backend_api.dart' show Backend;
 import 'common/names.dart' show Identifiers;
-import 'common/resolution.dart' show Resolution;
-import 'common/resolution.dart' show ResolutionWorkItem;
+import 'common/resolution.dart' show Resolution, ResolutionWorkItem;
+import 'common/registry.dart' show Registry;
 import 'common/tasks.dart' show CompilerTask;
 import 'common/work.dart' show WorkItem;
 import 'common.dart';
-import 'compiler.dart' show Compiler;
+import 'compiler.dart' show Compiler, GlobalDependencyRegistry;
+import 'core_types.dart' show CommonElements;
+import 'options.dart';
 import 'dart_types.dart' show DartType, InterfaceType;
 import 'elements/elements.dart'
     show
         AnalyzableElement,
         AstElement,
         ClassElement,
         Element,
         Entity,
         FunctionElement,
         LibraryElement,
         LocalFunctionElement,
         TypedElement;
 import 'native/native.dart' as native;
 import 'types/types.dart' show TypeMaskStrategy;
 import 'universe/selector.dart' show Selector;
 import 'universe/world_builder.dart';
 import 'universe/use.dart'
     show DynamicUse, StaticUse, StaticUseKind, TypeUse, TypeUseKind;
 import 'universe/world_impact.dart'
-    show ImpactUseCase, WorldImpact, WorldImpactVisitor;
+    show ImpactStrategy, ImpactUseCase, WorldImpact, WorldImpactVisitor;
 import 'util/util.dart' show Setlet;
+import 'world.dart' show OpenWorld;
 
 class EnqueueTask extends CompilerTask {
-  final ResolutionEnqueuer resolution;
-  final Enqueuer codegen;
+  ResolutionEnqueuer _resolution;
+  Enqueuer _codegen;
   final Compiler compiler;
 
   String get name => 'Enqueue';
 
   EnqueueTask(Compiler compiler)
-      : compiler = compiler,
-        resolution = new ResolutionEnqueuer(
-            compiler,
-            compiler.options.analyzeOnly && compiler.options.analyzeMain
-                ? const EnqueuerStrategy()
-                : const TreeShakingEnqueuerStrategy()),
-        codegen = compiler.backend.createCodegenEnqueuer(compiler),
+      : this.compiler = compiler,
         super(compiler.measurer) {
-    codegen.task = this;
-    resolution.task = this;
-
-    codegen.nativeEnqueuer = compiler.backend.nativeCodegenEnqueuer(codegen);
-    resolution.nativeEnqueuer =
-        compiler.backend.nativeResolutionEnqueuer(resolution);
+    _resolution = new ResolutionEnqueuer(
+        this,
+        compiler.options,
+        compiler.resolution,
+        compiler.enqueuerFilter,
+        compiler.options.analyzeOnly && compiler.options.analyzeMain
+            ? const EnqueuerStrategy()
+            : const TreeShakingEnqueuerStrategy(),
+        compiler.globalDependencies,
+        compiler.backend,
+        compiler.coreClasses,
+        compiler.cacheStrategy);
+    _codegen = compiler.backend.createCodegenEnqueuer(this, compiler);
   }
 
+  ResolutionEnqueuer get resolution => _resolution;
+  Enqueuer get codegen => _codegen;
+
   void forgetElement(Element element) {
-    resolution.forgetElement(element);
-    codegen.forgetElement(element);
+    resolution.forgetElement(element, compiler);
+    codegen.forgetElement(element, compiler);
   }
 }
 
 abstract class Enqueuer {
-  EnqueueTask task;
+  CompilerTask get task;
   WorldBuilder get universe;
-  native.NativeEnqueuer nativeEnqueuer; // Set by EnqueueTask
-  void forgetElement(Element element);
+  native.NativeEnqueuer get nativeEnqueuer;
+  void forgetElement(Element element, Compiler compiler);
   void processInstantiatedClassMembers(ClassElement cls);
   void processInstantiatedClassMember(ClassElement cls, Element member);
   void handleUnseenSelectorInternal(DynamicUse dynamicUse);
   void registerStaticUse(StaticUse staticUse);
   void registerStaticUseInternal(StaticUse staticUse);
   void registerDynamicUse(DynamicUse dynamicUse);
   void registerTypeUse(TypeUse typeUse);
 
   /// Returns [:true:] if this enqueuer is the resolution enqueuer.
   bool get isResolutionQueue;
@@ skipping 12 matching lines @@
   void addToWorkList(Element element);
 
   void enableIsolateSupport();
 
   void registerInstantiatedType(InterfaceType type);
   void forEach(void f(WorkItem work));
 
   /// Apply the [worldImpact] to this enqueuer. If the [impactSource] is provided
   /// the impact strategy will remove it from the element impact cache, if it is
   /// no longer needed.
-  void applyImpact(WorldImpact worldImpact, {Element impactSource});
+  void applyImpact(ImpactStrategy impactStrategy, WorldImpact worldImpact,
+      {Element impactSource});
   bool checkNoEnqueuedInvokedInstanceMethods();
   void logSummary(log(message));
 
   /// Returns [:true:] if [member] has been processed by this enqueuer.
   bool isProcessed(Element member);
 
   Iterable<Entity> get processedEntities;
 
   Iterable<ClassElement> get processedClasses;
 }
 
 /// [Enqueuer] which is specific to resolution.
 class ResolutionEnqueuer extends Enqueuer {
+  final CompilerTask task;
   final String name;
-  final Compiler compiler; // TODO(ahe): Remove this dependency.
+  final Resolution resolution;
+  final QueueFilter filter;
+  final CompilerOptions options;
+  final Backend backend;
+  final GlobalDependencyRegistry globalDependencies;
+  final CommonElements commonElements;
+  final native.NativeEnqueuer nativeEnqueuer;
+
   final EnqueuerStrategy strategy;
   final Map<String, Set<Element>> instanceMembersByName =
       new Map<String, Set<Element>>();
   final Map<String, Set<Element>> instanceFunctionsByName =
       new Map<String, Set<Element>>();
   final Set<ClassElement> _processedClasses = new Set<ClassElement>();
   Set<ClassElement> recentClasses = new Setlet<ClassElement>();
-  final ResolutionWorldBuilderImpl _universe =
-      new ResolutionWorldBuilderImpl(const TypeMaskStrategy());
-
+  final ResolutionWorldBuilderImpl _universe;
 
   bool queueIsClosed = false;
 
   WorldImpactVisitor impactVisitor;
 
-  ResolutionEnqueuer(Compiler compiler, this.strategy)
+  ImpactStrategy impactStrategy;
+
+  ResolutionEnqueuer(
+      this.task,
+      this.options,
+      this.resolution,
+      this.filter,
+      this.strategy,
+      this.globalDependencies,
+      Backend backend,
+      CommonElements commonElements,
+      CacheStrategy cacheStrategy)
       : this.name = 'resolution enqueuer',
-        this.compiler = compiler,
+        this.backend = backend,
+        this.commonElements = commonElements,
+        this.nativeEnqueuer = backend.nativeResolutionEnqueuer(),
         processedElements = new Set<AstElement>(),
         queue = new Queue<ResolutionWorkItem>(),
-        deferredQueue = new Queue<_DeferredAction>() {
+        deferredQueue = new Queue<_DeferredAction>(),
+        _universe = new ResolutionWorldBuilderImpl(
+            backend, commonElements, cacheStrategy, const TypeMaskStrategy()) {
     impactVisitor = new _EnqueuerImpactVisitor(this);
   }
 
-  Resolution get resolution => compiler.resolution;
+  ResolutionWorldBuilder get universe => _universe;
 
-  ResolutionWorldBuilder get universe => _universe;
+  OpenWorld get openWorld => universe.openWorld;
 
   bool get queueIsEmpty => queue.isEmpty;
 
-  QueueFilter get filter => compiler.enqueuerFilter;
-
-  DiagnosticReporter get reporter => compiler.reporter;
+  DiagnosticReporter get reporter => resolution.reporter;
 
   bool isClassProcessed(ClassElement cls) => _processedClasses.contains(cls);
 
   Iterable<ClassElement> get processedClasses => _processedClasses;
 
   /**
    * Documentation wanted -- johnniwinther
    *
    * Invariant: [element] must be a declaration element.
    */
   void addToWorkList(Element element) {
     assert(invariant(element, element.isDeclaration));
-    if (internalAddToWorkList(element) && compiler.options.dumpInfo) {
-      // TODO(sigmund): add other missing dependencies (internals, selectors
-      // enqueued after allocations), also enable only for the codegen enqueuer.
-      compiler.dumpInfoTask
-          .registerDependency(compiler.currentElement, element);
-    }
+    internalAddToWorkList(element);
+  }
+
+  void applyImpact(ImpactStrategy impactStrategy, WorldImpact worldImpact,
+      {Element impactSource}) {
+    impactStrategy.visitImpact(
+        impactSource, worldImpact, impactVisitor, impactUse);
   }
 
   void registerInstantiatedType(InterfaceType type) {
     _registerInstantiatedType(type, globalDependency: true);
   }
 
-  void applyImpact(WorldImpact worldImpact, {Element impactSource}) {
-    compiler.impactStrategy
-        .visitImpact(impactSource, worldImpact, impactVisitor, impactUse);
-  }
-
   void _registerInstantiatedType(InterfaceType type,
       {bool mirrorUsage: false,
       bool nativeUsage: false,
       bool globalDependency: false}) {
     task.measure(() {
       ClassElement cls = type.element;
       cls.ensureResolved(resolution);
-      bool isNative = compiler.backend.isNative(cls);
+      bool isNative = backend.isNative(cls);
       _universe.registerTypeInstantiation(type,
           isNative: isNative,
           byMirrors: mirrorUsage, onImplemented: (ClassElement cls) {
-            compiler.backend.registerImplementedClass(cls, this);
+            backend.registerImplementedClass(cls, this);
       });
       if (globalDependency && !mirrorUsage) {
-        compiler.globalDependencies.registerDependency(type.element);
+        globalDependencies.registerDependency(type.element);
       }
       if (nativeUsage) {
         nativeEnqueuer.onInstantiatedType(type);
       }
-      compiler.backend.registerInstantiatedType(type);
+      backend.registerInstantiatedType(type);
       // TODO(johnniwinther): Share this reasoning with [Universe].
       if (!cls.isAbstract || isNative || mirrorUsage) {
         processInstantiatedClass(cls);
       }
     });
   }
 
   bool checkNoEnqueuedInvokedInstanceMethods() {
     return filter.checkNoEnqueuedInvokedInstanceMethods(this);
   }
 
   void processInstantiatedClassMembers(ClassElement cls) {
     strategy.processInstantiatedClass(this, cls);
   }
 
   void processInstantiatedClassMember(ClassElement cls, Element member) {
     assert(invariant(member, member.isDeclaration));
     if (isProcessed(member)) return;
     if (!member.isInstanceMember) return;
     String memberName = member.name;
 
     if (member.isField) {
       // The obvious thing to test here would be "member.isNative",
       // however, that only works after metadata has been parsed/analyzed,
       // and that may not have happened yet.
       // So instead we use the enclosing class, which we know have had
       // its metadata parsed and analyzed.
       // Note: this assumes that there are no non-native fields on native
       // classes, which may not be the case when a native class is subclassed.
-      if (compiler.backend.isNative(cls)) {
-        compiler.openWorld.registerUsedElement(member);
-        if (_universe.hasInvokedGetter(member, compiler.openWorld) ||
-            _universe.hasInvocation(member, compiler.openWorld)) {
+      if (backend.isNative(cls)) {
+        openWorld.registerUsedElement(member);
+        if (_universe.hasInvokedGetter(member, openWorld) ||
+            _universe.hasInvocation(member, openWorld)) {
           addToWorkList(member);
           return;
         }
-        if (_universe.hasInvokedSetter(member, compiler.openWorld)) {
+        if (_universe.hasInvokedSetter(member, openWorld)) {
           addToWorkList(member);
           return;
         }
         // Native fields need to go into instanceMembersByName as they
         // are virtual instantiation points and escape points.
       } else {
         // All field initializers must be resolved as they could
         // have an observable side-effect (and cannot be tree-shaken
         // away).
         addToWorkList(member);
         return;
       }
     } else if (member.isFunction) {
       FunctionElement function = member;
       function.computeType(resolution);
       if (function.name == Identifiers.noSuchMethod_) {
         registerNoSuchMethod(function);
       }
       if (function.name == Identifiers.call && !cls.typeVariables.isEmpty) {
         registerCallMethodWithFreeTypeVariables(function);
       }
       // If there is a property access with the same name as a method we
       // need to emit the method.
-      if (_universe.hasInvokedGetter(function, compiler.openWorld)) {
+      if (_universe.hasInvokedGetter(function, openWorld)) {
         registerClosurizedMember(function);
         addToWorkList(function);
         return;
       }
       // Store the member in [instanceFunctionsByName] to catch
       // getters on the function.
       instanceFunctionsByName
           .putIfAbsent(memberName, () => new Set<Element>())
           .add(member);
-      if (_universe.hasInvocation(function, compiler.openWorld)) {
+      if (_universe.hasInvocation(function, openWorld)) {
         addToWorkList(function);
         return;
       }
     } else if (member.isGetter) {
       FunctionElement getter = member;
       getter.computeType(resolution);
-      if (_universe.hasInvokedGetter(getter, compiler.openWorld)) {
+      if (_universe.hasInvokedGetter(getter, openWorld)) {
         addToWorkList(getter);
         return;
       }
       // We don't know what selectors the returned closure accepts. If
       // the set contains any selector we have to assume that it matches.
-      if (_universe.hasInvocation(getter, compiler.openWorld)) {
+      if (_universe.hasInvocation(getter, openWorld)) {
         addToWorkList(getter);
         return;
       }
     } else if (member.isSetter) {
       FunctionElement setter = member;
       setter.computeType(resolution);
-      if (_universe.hasInvokedSetter(setter, compiler.openWorld)) {
+      if (_universe.hasInvokedSetter(setter, openWorld)) {
         addToWorkList(setter);
         return;
       }
     }
 
     // The element is not yet used. Add it to the list of instance
     // members to still be processed.
     instanceMembersByName
         .putIfAbsent(memberName, () => new Set<Element>())
         .add(member);
   }
 
   void processInstantiatedClass(ClassElement cls) {
     task.measure(() {
       if (_processedClasses.contains(cls)) return;
       // The class must be resolved to compute the set of all
       // supertypes.
       cls.ensureResolved(resolution);
 
       void processClass(ClassElement superclass) {
         if (_processedClasses.contains(superclass)) return;
 
         _processedClasses.add(superclass);
         recentClasses.add(superclass);
         superclass.ensureResolved(resolution);
         superclass.implementation.forEachMember(processInstantiatedClassMember);
-        if (!compiler.serialization.isDeserialized(superclass)) {
-          compiler.resolver.checkClass(superclass);
-        }
+        resolution.ensureClassMembers(superclass);
         // We only tell the backend once that [superclass] was instantiated, so
         // any additional dependencies must be treated as global
         // dependencies.
-        compiler.backend.registerInstantiatedClass(superclass, this);
+        backend.registerInstantiatedClass(superclass, this);
       }
 
       ClassElement superclass = cls;
       while (superclass != null) {
         processClass(superclass);
         superclass = superclass.superclass;
       }
     });
   }
 
@@ skipping 29 matching lines @@
   }
 
   void handleUnseenSelector(DynamicUse universeSelector) {
     strategy.processDynamicUse(this, universeSelector);
   }
 
   void handleUnseenSelectorInternal(DynamicUse dynamicUse) {
     Selector selector = dynamicUse.selector;
     String methodName = selector.name;
     processInstanceMembers(methodName, (Element member) {
-      if (dynamicUse.appliesUnnamed(member, compiler.openWorld)) {
+      if (dynamicUse.appliesUnnamed(member, openWorld)) {
         if (member.isFunction && selector.isGetter) {
           registerClosurizedMember(member);
         }
         addToWorkList(member);
         return true;
       }
       return false;
     });
     if (selector.isGetter) {
       processInstanceFunctions(methodName, (Element member) {
-        if (dynamicUse.appliesUnnamed(member, compiler.openWorld)) {
+        if (dynamicUse.appliesUnnamed(member, openWorld)) {
           registerClosurizedMember(member);
           return true;
         }
         return false;
       });
     }
   }
 
   /**
    * Documentation wanted -- johnniwinther
    *
    * Invariant: [element] must be a declaration element.
    */
   void registerStaticUse(StaticUse staticUse) {
     strategy.processStaticUse(this, staticUse);
   }
 
   void registerStaticUseInternal(StaticUse staticUse) {
     Element element = staticUse.element;
     assert(invariant(element, element.isDeclaration,
         message: "Element ${element} is not the declaration."));
     _universe.registerStaticUse(staticUse);
-    compiler.backend.registerStaticUse(this, element);
+    backend.registerStaticUse(this, element);
     bool addElement = true;
     switch (staticUse.kind) {
       case StaticUseKind.STATIC_TEAR_OFF:
-        compiler.backend.registerGetOfStaticFunction(this);
+        backend.registerGetOfStaticFunction(this);
         break;
       case StaticUseKind.FIELD_GET:
       case StaticUseKind.FIELD_SET:
       case StaticUseKind.CLOSURE:
         // TODO(johnniwinther): Avoid this. Currently [FIELD_GET] and
         // [FIELD_SET] contains [BoxFieldElement]s which we cannot enqueue.
         // Also [CLOSURE] contains [LocalFunctionElement] which we cannot
         // enqueue.
         LocalFunctionElement closure = staticUse.element;
         if (closure.type.containsTypeVariables) {
@@ skipping 32 matching lines @@
       case TypeUseKind.NATIVE_INSTANTIATION:
         _registerInstantiatedType(type,
             nativeUsage: true, globalDependency: true);
         break;
       case TypeUseKind.IS_CHECK:
       case TypeUseKind.AS_CAST:
       case TypeUseKind.CATCH_TYPE:
         _registerIsCheck(type);
         break;
       case TypeUseKind.CHECKED_MODE_CHECK:
-        if (compiler.options.enableTypeAssertions) {
+        if (options.enableTypeAssertions) {
           _registerIsCheck(type);
         }
         break;
       case TypeUseKind.TYPE_LITERAL:
         break;
     }
   }
 
   void _registerIsCheck(DartType type) {
-    type = _universe.registerIsCheck(type, compiler);
+    type = _universe.registerIsCheck(type, resolution);
     // Even in checked mode, type annotations for return type and argument
     // types do not imply type checks, so there should never be a check
     // against the type variable of a typedef.
     assert(!type.isTypeVariable || !type.element.enclosingElement.isTypedef);
   }
 
   void registerCallMethodWithFreeTypeVariables(Element element) {
-    compiler.backend.registerCallMethodWithFreeTypeVariables(element, this);
+    backend.registerCallMethodWithFreeTypeVariables(element, this);
     _universe.callMethodsWithFreeTypeVariables.add(element);
   }
 
   void registerClosurizedMember(TypedElement element) {
     assert(element.isInstanceMember);
     if (element.computeType(resolution).containsTypeVariables) {
-      compiler.backend.registerClosureWithFreeTypeVariables(element, this);
+      backend.registerClosureWithFreeTypeVariables(element, this);
       _universe.closuresWithFreeTypeVariables.add(element);
     }
-    compiler.backend.registerBoundClosure(this);
+    backend.registerBoundClosure(this);
     _universe.closurizedMembers.add(element);
   }
 
   void forEach(void f(WorkItem work)) {
     do {
       while (queue.isNotEmpty) {
         // TODO(johnniwinther): Find an optimal process order.
         filter.processWorkItem(f, queue.removeLast());
       }
       List recents = recentClasses.toList(growable: false);
@@ skipping 30 matching lines @@
   bool isProcessed(Element member) => processedElements.contains(member);
 
   /// Returns `true` if [element] has been processed by the resolution enqueuer.
   bool hasBeenProcessed(Element element) {
     return processedElements.contains(element.analyzableElement.declaration);
   }
 
   /// Registers [element] as processed by the resolution enqueuer.
   void registerProcessedElement(AstElement element) {
     processedElements.add(element);
-    compiler.backend.onElementResolved(element);
+    backend.onElementResolved(element);
   }
 
   /**
    * Adds [element] to the work list if it has not already been processed.
    *
    * Returns [true] if the element was actually added to the queue.
    */
   bool internalAddToWorkList(Element element) {
     if (element.isMalformed) return false;
 
     assert(invariant(element, element is AnalyzableElement,
         message: 'Element $element is not analyzable.'));
     if (hasBeenProcessed(element)) return false;
     if (queueIsClosed) {
       throw new SpannableAssertionFailure(
           element, "Resolution work list is closed. Trying to add $element.");
     }
 
-    compiler.openWorld.registerUsedElement(element);
+    openWorld.registerUsedElement(element);
 
-    ResolutionWorkItem workItem = compiler.resolution.createWorkItem(element);
+    ResolutionWorkItem workItem = resolution.createWorkItem(element);
     queue.add(workItem);
 
     // Enable isolate support if we start using something from the isolate
     // library, or timers for the async library.  We exclude constant fields,
     // which are ending here because their initializing expression is compiled.
     LibraryElement library = element.library;
-    if (!compiler.hasIsolateSupport && (!element.isField || !element.isConst)) {
+    if (!universe.hasIsolateSupport && (!element.isField || !element.isConst)) {
       String uri = library.canonicalUri.toString();
       if (uri == 'dart:isolate') {
         enableIsolateSupport();
       } else if (uri == 'dart:async') {
         if (element.name == '_createTimer' ||
             element.name == '_createPeriodicTimer') {
           // The [:Timer:] class uses the event queue of the isolate
           // library, so we make sure that event queue is generated.
           enableIsolateSupport();
         }
       }
     }
 
     if (element.isGetter && element.name == Identifiers.runtimeType_) {
       // Enable runtime type support if we discover a getter called runtimeType.
       // We have to enable runtime type before hitting the codegen, so
       // that constructors know whether they need to generate code for
       // runtime type.
-      compiler.enabledRuntimeType = true;
+      _universe.hasRuntimeTypeSupport = true;
       // TODO(ahe): Record precise dependency here.
-      compiler.backend.registerRuntimeType(this);
-    } else if (compiler.commonElements.isFunctionApplyMethod(element)) {
-      compiler.enabledFunctionApply = true;
+      backend.registerRuntimeType(this);
+    } else if (commonElements.isFunctionApplyMethod(element)) {
+      _universe.hasFunctionApplySupport = true;
     }
 
     return true;
   }
 
   void registerNoSuchMethod(Element element) {
-    compiler.backend.registerNoSuchMethod(element);
+    backend.registerNoSuchMethod(element);
   }
 
   void enableIsolateSupport() {
-    compiler.hasIsolateSupport = true;
-    compiler.backend.enableIsolateSupport(this);
+    _universe.hasIsolateSupport = true;
+    backend.enableIsolateSupport(this);
   }
 
   /**
    * Adds an action to the deferred task queue.
    *
    * The action is performed the next time the resolution queue has been
    * emptied.
    *
    * The queue is processed in FIFO order.
    */
   void addDeferredAction(Element element, void action()) {
     if (queueIsClosed) {
       throw new SpannableAssertionFailure(
           element,
           "Resolution work list is closed. "
           "Trying to add deferred action for $element");
     }
     deferredQueue.add(new _DeferredAction(element, action));
   }
 
   /// [onQueueEmpty] is called whenever the queue is drained. [recentClasses]
   /// contains the set of all classes seen for the first time since
   /// [onQueueEmpty] was called last. A return value of [true] indicates that
   /// the [recentClasses] have been processed and may be cleared. If [false] is
   /// returned, [onQueueEmpty] will be called once the queue is empty again (or
   /// still empty) and [recentClasses] will be a superset of the current value.
   bool onQueueEmpty(Iterable<ClassElement> recentClasses) {
     _emptyDeferredQueue();
 
-    return compiler.backend.onQueueEmpty(this, recentClasses);
+    return backend.onQueueEmpty(this, recentClasses);
   }
 
   void emptyDeferredQueueForTesting() => _emptyDeferredQueue();
 
   void _emptyDeferredQueue() {
     while (!deferredQueue.isEmpty) {
       _DeferredAction task = deferredQueue.removeFirst();
       reporter.withCurrentElement(task.element, task.action);
     }
   }
 
-  void forgetElement(Element element) {
+  void forgetElement(Element element, Compiler compiler) {
     _universe.forgetElement(element, compiler);
     _processedClasses.remove(element);
     instanceMembersByName[element.name]?.remove(element);
     instanceFunctionsByName[element.name]?.remove(element);
     processedElements.remove(element);
   }
 }
 
 /// Parameterizes filtering of which work items are enqueued.
 class QueueFilter {
@@ skipping 79 matching lines @@
 }
 
 typedef void _DeferredActionFunction();
 
 class _DeferredAction {
   final Element element;
   final _DeferredActionFunction action;
 
   _DeferredAction(this.element, this.action);
 }