Move dart2js from sdk/lib/_internal/compiler to pkg/compiler

sdk/lib/_internal/compiler/implementation/inferrer/type_graph_inferrer.dart

Index: sdk/lib/_internal/compiler/implementation/inferrer/type_graph_inferrer.dart
diff --git a/sdk/lib/_internal/compiler/implementation/inferrer/type_graph_inferrer.dart b/sdk/lib/_internal/compiler/implementation/inferrer/type_graph_inferrer.dart
deleted file mode 100644
index ae3427a55e791a355daa0ad0478488cb874ccdeb..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/compiler/implementation/inferrer/type_graph_inferrer.dart
+++ /dev/null
@@ -1,1322 +0,0 @@
-// Copyright (c) 2013, 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 type_graph_inferrer;
-
-import 'dart:collection' show Queue, IterableBase;
-
-import '../constants/expressions.dart';
-import '../constants/values.dart';
-import '../cps_ir/cps_ir_nodes.dart' as cps_ir
-    show Node;
-import '../dart_types.dart'
-    show DartType,
-         FunctionType,
-         InterfaceType,
-         TypeKind;
-import '../dart2jslib.dart'
-    show ClassWorld,
-         Compiler,
-         Constant,
-         FunctionConstant,
-         invariant,
-         TreeElementMapping;
-import '../elements/elements.dart';
-import '../native/native.dart' as native;
-import '../tree/tree.dart' as ast
-    show DartString,
-         Node,
-         TryStatement;
-import '../types/types.dart'
-    show ContainerTypeMask,
-         DictionaryTypeMask,
-         MapTypeMask,
-         TypeMask,
-         TypesInferrer,
-         ValueTypeMask;
-import '../universe/universe.dart'
-    show Selector,
-         SideEffects,
-         TypedSelector;
-import '../util/util.dart'
-    show ImmutableEmptySet,
-         Setlet,
-         Spannable;
-
-import 'inferrer_visitor.dart'
-    show ArgumentsTypes,
-         TypeSystem;
-import 'simple_types_inferrer.dart';
-
-part 'closure_tracer.dart';
-part 'list_tracer.dart';
-part 'map_tracer.dart';
-part 'node_tracer.dart';
-part 'type_graph_nodes.dart';
-
-bool _VERBOSE = false;
-bool _PRINT_SUMMARY = false;
-final _ANOMALY_WARN = false;
-
-class TypeInformationSystem extends TypeSystem<TypeInformation> {
-  final Compiler compiler;
-  final ClassWorld classWorld;
-
-  /// [ElementTypeInformation]s for elements.
-  final Map<Element, TypeInformation> typeInformations =
-      new Map<Element, TypeInformation>();
-
-  /// [ListTypeInformation] for allocated lists.
-  final Map<ast.Node, TypeInformation> allocatedLists =
-      new Map<ast.Node, TypeInformation>();
-
-  /// [MapTypeInformation] for allocated Maps.
-  final Map<ast.Node, TypeInformation> allocatedMaps =
-      new Map<ast.Node, TypeInformation>();
-
-  /// Closures found during the analysis.
-  final Set<TypeInformation> allocatedClosures = new Set<TypeInformation>();
-
-  /// Cache of [ConcreteTypeInformation].
-  final Map<TypeMask, TypeInformation> concreteTypes =
-      new Map<TypeMask, TypeInformation>();
-
-  /// List of [TypeInformation]s allocated inside method bodies (calls,
-  /// narrowing, phis, and containers).
-  final List<TypeInformation> allocatedTypes = <TypeInformation>[];
-
-  TypeInformationSystem(Compiler compiler)
-      : this.compiler = compiler,
-        this.classWorld = compiler.world {
-    nonNullEmptyType = getConcreteTypeFor(const TypeMask.nonNullEmpty());
-  }
-
-  /// Used to group [TypeInformation] nodes by the element that triggered their
-  /// creation.
-  MemberTypeInformation _currentMember = null;
-  MemberTypeInformation get currentMember => _currentMember;
-
-  void withMember(MemberElement element, action) {
-    assert(invariant(element, _currentMember == null,
-        message: "Already constructing graph for $_currentMember."));
-    _currentMember = getInferredTypeOf(element);
-    action();
-    _currentMember = null;
-  }
-
-  TypeInformation nullTypeCache;
-  TypeInformation get nullType {
-    if (nullTypeCache != null) return nullTypeCache;
-    return nullTypeCache = getConcreteTypeFor(compiler.typesTask.nullType);
-  }
-
-  TypeInformation intTypeCache;
-  TypeInformation get intType {
-    if (intTypeCache != null) return intTypeCache;
-    return intTypeCache = getConcreteTypeFor(compiler.typesTask.intType);
-  }
-
-  TypeInformation uint32TypeCache;
-  TypeInformation get uint32Type {
-    if (uint32TypeCache != null) return uint32TypeCache;
-    return uint32TypeCache = getConcreteTypeFor(compiler.typesTask.uint32Type);
-  }
-
-  TypeInformation uint31TypeCache;
-  TypeInformation get uint31Type {
-    if (uint31TypeCache != null) return uint31TypeCache;
-    return uint31TypeCache = getConcreteTypeFor(compiler.typesTask.uint31Type);
-  }
-
-  TypeInformation positiveIntTypeCache;
-  TypeInformation get positiveIntType {
-    if (positiveIntTypeCache != null) return positiveIntTypeCache;
-    return positiveIntTypeCache =
-        getConcreteTypeFor(compiler.typesTask.positiveIntType);
-  }
-
-  TypeInformation doubleTypeCache;
-  TypeInformation get doubleType {
-    if (doubleTypeCache != null) return doubleTypeCache;
-    return doubleTypeCache = getConcreteTypeFor(compiler.typesTask.doubleType);
-  }
-
-  TypeInformation numTypeCache;
-  TypeInformation get numType {
-    if (numTypeCache != null) return numTypeCache;
-    return numTypeCache = getConcreteTypeFor(compiler.typesTask.numType);
-  }
-
-  TypeInformation boolTypeCache;
-  TypeInformation get boolType {
-    if (boolTypeCache != null) return boolTypeCache;
-    return boolTypeCache = getConcreteTypeFor(compiler.typesTask.boolType);
-  }
-
-  TypeInformation functionTypeCache;
-  TypeInformation get functionType {
-    if (functionTypeCache != null) return functionTypeCache;
-    return functionTypeCache =
-        getConcreteTypeFor(compiler.typesTask.functionType);
-  }
-
-  TypeInformation listTypeCache;
-  TypeInformation get listType {
-    if (listTypeCache != null) return listTypeCache;
-    return listTypeCache = getConcreteTypeFor(compiler.typesTask.listType);
-  }
-
-  TypeInformation constListTypeCache;
-  TypeInformation get constListType {
-    if (constListTypeCache != null) return constListTypeCache;
-    return constListTypeCache =
-        getConcreteTypeFor(compiler.typesTask.constListType);
-  }
-
-  TypeInformation fixedListTypeCache;
-  TypeInformation get fixedListType {
-    if (fixedListTypeCache != null) return fixedListTypeCache;
-    return fixedListTypeCache =
-        getConcreteTypeFor(compiler.typesTask.fixedListType);
-  }
-
-  TypeInformation growableListTypeCache;
-  TypeInformation get growableListType {
-    if (growableListTypeCache != null) return growableListTypeCache;
-    return growableListTypeCache =
-        getConcreteTypeFor(compiler.typesTask.growableListType);
-  }
-
-  TypeInformation mapTypeCache;
-  TypeInformation get mapType {
-    if (mapTypeCache != null) return mapTypeCache;
-    return mapTypeCache = getConcreteTypeFor(compiler.typesTask.mapType);
-  }
-
-  TypeInformation constMapTypeCache;
-  TypeInformation get constMapType {
-    if (constMapTypeCache != null) return constMapTypeCache;
-    return constMapTypeCache =
-        getConcreteTypeFor(compiler.typesTask.constMapType);
-  }
-
-  TypeInformation stringTypeCache;
-  TypeInformation get stringType {
-    if (stringTypeCache != null) return stringTypeCache;
-    return stringTypeCache = getConcreteTypeFor(compiler.typesTask.stringType);
-  }
-
-  TypeInformation typeTypeCache;
-  TypeInformation get typeType {
-    if (typeTypeCache != null) return typeTypeCache;
-    return typeTypeCache = getConcreteTypeFor(compiler.typesTask.typeType);
-  }
-
-  TypeInformation dynamicTypeCache;
-  TypeInformation get dynamicType {
-    if (dynamicTypeCache != null) return dynamicTypeCache;
-    return dynamicTypeCache =
-        getConcreteTypeFor(compiler.typesTask.dynamicType);
-  }
-
-  TypeInformation nonNullEmptyType;
-
-  TypeInformation stringLiteralType(ast.DartString value) {
-    return new StringLiteralTypeInformation(
-        value, compiler.typesTask.stringType);
-  }
-
-  TypeInformation computeLUB(TypeInformation firstType,
-                             TypeInformation secondType) {
-    if (firstType == null) return secondType;
-    if (firstType == secondType) return firstType;
-    if (firstType == nonNullEmptyType) return secondType;
-    if (secondType == nonNullEmptyType) return firstType;
-    if (firstType == dynamicType || secondType == dynamicType) {
-      return dynamicType;
-    }
-    return getConcreteTypeFor(
-        firstType.type.union(secondType.type, classWorld));
-  }
-
-  bool selectorNeedsUpdate(TypeInformation info, Selector selector)
-  {
-    return info.type != selector.mask;
-  }
-
-  TypeInformation refineReceiver(Selector selector, TypeInformation receiver) {
-    if (receiver.type.isExact) return receiver;
-    TypeMask otherType = compiler.world.allFunctions.receiverType(selector);
-    // If this is refining to nullable subtype of `Object` just return
-    // the receiver. We know the narrowing is useless.
-    if (otherType.isNullable && otherType.containsAll(classWorld)) {
-      return receiver;
-    }
-    assert(TypeMask.assertIsNormalized(otherType, classWorld));
-    TypeInformation newType = new NarrowTypeInformation(receiver, otherType);
-    allocatedTypes.add(newType);
-    return newType;
-  }
-
-  TypeInformation narrowType(TypeInformation type,
-                             DartType annotation,
-                             {bool isNullable: true}) {
-    if (annotation.treatAsDynamic) return type;
-    if (annotation.isVoid) return nullType;
-    if (annotation.element == classWorld.objectClass && isNullable) return type;
-    TypeMask otherType;
-    if (annotation.isTypedef || annotation.isFunctionType) {
-      otherType = functionType.type;
-    } else if (annotation.isTypeVariable) {
-      // TODO(ngeoffray): Narrow to bound.
-      return type;
-    } else {
-      assert(annotation.isInterfaceType);
-      otherType = annotation.element == classWorld.objectClass
-          ? dynamicType.type.nonNullable()
-          : new TypeMask.nonNullSubtype(annotation.element, classWorld);
-    }
-    if (isNullable) otherType = otherType.nullable();
-    if (type.type.isExact) {
-      return type;
-    } else {
-      assert(TypeMask.assertIsNormalized(otherType, classWorld));
-      TypeInformation newType = new NarrowTypeInformation(type, otherType);
-      allocatedTypes.add(newType);
-      return newType;
-    }
-  }
-
-  ElementTypeInformation getInferredTypeOf(Element element) {
-    element = element.implementation;
-    return typeInformations.putIfAbsent(element, () {
-      return new ElementTypeInformation(element, this);
-    });
-  }
-
-  ConcreteTypeInformation getConcreteTypeFor(TypeMask mask) {
-    assert(mask != null);
-    return concreteTypes.putIfAbsent(mask, () {
-      return new ConcreteTypeInformation(mask);
-    });
-  }
-
-  String getInferredSignatureOf(FunctionElement function) {
-    ElementTypeInformation info = getInferredTypeOf(function);
-    FunctionElement impl = function.implementation;
-    FunctionSignature signature = impl.functionSignature;
-    var res = "";
-    signature.forEachParameter((Element parameter) {
-      TypeInformation type = getInferredTypeOf(parameter);
-      res += "${res.isEmpty ? '(' : ', '}${type.type} ${parameter.name}";
-    });
-    res += ") -> ${info.type}";
-    return res;
-  }
-
-  TypeInformation nonNullSubtype(ClassElement type) {
-    return getConcreteTypeFor(
-        new TypeMask.nonNullSubtype(type.declaration, classWorld));
-  }
-
-  TypeInformation nonNullSubclass(ClassElement type) {
-    return getConcreteTypeFor(
-        new TypeMask.nonNullSubclass(type.declaration, classWorld));
-  }
-
-  TypeInformation nonNullExact(ClassElement type) {
-    return getConcreteTypeFor(
-        new TypeMask.nonNullExact(type.declaration, classWorld));
-  }
-
-  TypeInformation nonNullEmpty() {
-    return nonNullEmptyType;
-  }
-
-  bool isNull(TypeInformation type) {
-    return type == nullType;
-  }
-
-  TypeInformation allocateList(TypeInformation type,
-                               ast.Node node,
-                               Element enclosing,
-                               [TypeInformation elementType, int length]) {
-    bool isTypedArray =
-        compiler.typedDataClass != null &&
-        classWorld.isInstantiated(compiler.typedDataClass) &&
-        type.type.satisfies(compiler.typedDataClass, classWorld);
-    bool isConst = (type.type == compiler.typesTask.constListType);
-    bool isFixed = (type.type == compiler.typesTask.fixedListType) ||
-                   isConst ||
-                   isTypedArray;
-    bool isElementInferred = isConst || isTypedArray;
-
-    int inferredLength = isFixed ? length : null;
-    TypeMask elementTypeMask = isElementInferred
-        ? elementType.type
-        : dynamicType.type;
-    ContainerTypeMask mask = new ContainerTypeMask(
-        type.type, node, enclosing, elementTypeMask, inferredLength);
-    ElementInContainerTypeInformation element =
-        new ElementInContainerTypeInformation(currentMember, elementType);
-    element.inferred = isElementInferred;
-
-    allocatedTypes.add(element);
-    return allocatedLists[node] =
-        new ListTypeInformation(currentMember, mask, element, length);
-  }
-
-  TypeInformation allocateClosure(ast.Node node, Element element) {
-    TypeInformation result =
-        new ClosureTypeInformation(currentMember, node, element);
-    allocatedClosures.add(result);
-    return result;
-  }
-
-  TypeInformation allocateMap(ConcreteTypeInformation type,
-                              ast.Node node,
-                              Element element,
-                              [List<TypeInformation> keyTypes,
-                               List<TypeInformation> valueTypes]) {
-    assert(keyTypes.length == valueTypes.length);
-    bool isFixed = (type.type == compiler.typesTask.constMapType);
-
-    TypeMask keyType, valueType;
-    if (isFixed) {
-      keyType = keyTypes.fold(nonNullEmptyType.type,
-          (type, info) => type.union(info.type, classWorld));
-      valueType = valueTypes.fold(nonNullEmptyType.type,
-          (type, info) => type.union(info.type, classWorld));
-    } else {
-      keyType = valueType = dynamicType.type;
-    }
-    MapTypeMask mask = new MapTypeMask(type.type,
-                                       node,
-                                       element,
-                                       keyType,
-                                       valueType);
-
-    TypeInformation keyTypeInfo =
-        new KeyInMapTypeInformation(currentMember, null);
-    TypeInformation valueTypeInfo =
-        new ValueInMapTypeInformation(currentMember, null);
-    allocatedTypes.add(keyTypeInfo);
-    allocatedTypes.add(valueTypeInfo);
-
-    MapTypeInformation map =
-        new MapTypeInformation(currentMember, mask, keyTypeInfo, valueTypeInfo);
-
-    for (int i = 0; i < keyTypes.length; ++i) {
-      TypeInformation newType =
-          map.addEntryAssignment(keyTypes[i], valueTypes[i], true);
-      if (newType != null) allocatedTypes.add(newType);
-    }
-
-    // Shortcut: If we already have a first approximation of the key/value type,
-    // start propagating it early.
-    if (isFixed) map.markAsInferred();
-
-    allocatedMaps[node] = map;
-    return map;
-  }
-
-  Selector newTypedSelector(TypeInformation info, Selector selector) {
-    // Only type the selector if [info] is concrete, because the other
-    // kinds of [TypeInformation] have the empty type at this point of
-    // analysis.
-    return info.isConcrete
-        ? new TypedSelector(info.type, selector, classWorld)
-        : selector;
-  }
-
-  TypeInformation allocateDiamondPhi(TypeInformation firstInput,
-                                     TypeInformation secondInput) {
-    PhiElementTypeInformation result =
-        new PhiElementTypeInformation(currentMember, null, false, null);
-    result.addAssignment(firstInput);
-    result.addAssignment(secondInput);
-    allocatedTypes.add(result);
-    return result;
-  }
-
-  PhiElementTypeInformation _addPhi(ast.Node node,
-                                    Local variable,
-                                    inputType,
-                                    bool isLoop) {
-    PhiElementTypeInformation result =
-        new PhiElementTypeInformation(currentMember, node, isLoop, variable);
-    allocatedTypes.add(result);
-    result.addAssignment(inputType);
-    return result;
-  }
-
-  PhiElementTypeInformation allocatePhi(ast.Node node,
-                                        Local variable,
-                                        inputType) {
-    // Check if [inputType] is a phi for a local updated in
-    // the try/catch block [node]. If it is, no need to allocate a new
-    // phi.
-    if (inputType is PhiElementTypeInformation &&
-        inputType.branchNode == node &&
-        inputType.branchNode is ast.TryStatement) {
-      return inputType;
-    }
-    return _addPhi(node, variable, inputType, false);
-  }
-
-  PhiElementTypeInformation allocateLoopPhi(ast.Node node,
-                                            Local variable,
-                                            inputType) {
-    return _addPhi(node, variable, inputType, true);
-  }
-
-  TypeInformation simplifyPhi(ast.Node node,
-                              Local variable,
-                              PhiElementTypeInformation phiType) {
-    assert(phiType.branchNode == node);
-    if (phiType.assignments.length == 1) return phiType.assignments.first;
-    return phiType;
-  }
-
-  PhiElementTypeInformation addPhiInput(Local variable,
-                                        PhiElementTypeInformation phiType,
-                                        TypeInformation newType) {
-    phiType.addAssignment(newType);
-    return phiType;
-  }
-
-  TypeMask computeTypeMask(Iterable<TypeInformation> assignments) {
-    return joinTypeMasks(assignments.map((e) => e.type));
-  }
-
-  TypeMask joinTypeMasks(Iterable<TypeMask> masks) {
-    TypeMask newType = const TypeMask.nonNullEmpty();
-    for (TypeMask mask in masks) {
-      newType = newType.union(mask, classWorld);
-    }
-    return newType.containsAll(classWorld) ? dynamicType.type : newType;
-  }
-}
-
-/**
- * A work queue for the inferrer. It filters out nodes that are tagged as
- * [TypeInformation.doNotEnqueue], as well as ensures through
- * [TypeInformation.inQueue] that a node is in the queue only once at
- * a time.
- */
-class WorkQueue {
-  final Queue<TypeInformation> queue = new Queue<TypeInformation>();
-
-  void add(TypeInformation element) {
-    if (element.doNotEnqueue) return;
-    if (element.inQueue) return;
-    queue.addLast(element);
-    element.inQueue = true;
-  }
-
-  void addAll(Iterable<TypeInformation> all) {
-    all.forEach(add);
-  }
-
-  TypeInformation remove() {
-    TypeInformation element = queue.removeFirst();
-    element.inQueue = false;
-    return element;
-  }
-
-  bool get isEmpty => queue.isEmpty;
-
-  int get length => queue.length;
-}
-
-/**
- * An inferencing engine that computes a call graph of
- * [TypeInformation] nodes by visiting the AST of the application, and
- * then does the inferencing on the graph.
- *
- */
-class TypeGraphInferrerEngine
-    extends InferrerEngine<TypeInformation, TypeInformationSystem> {
-  final Map<Element, TypeInformation> defaultTypeOfParameter =
-      new Map<Element, TypeInformation>();
-  final List<CallSiteTypeInformation> allocatedCalls =
-      <CallSiteTypeInformation>[];
-  final WorkQueue workQueue = new WorkQueue();
-  final Element mainElement;
-  final Set<Element> analyzedElements = new Set<Element>();
-
-  /// The maximum number of times we allow a node in the graph to
-  /// change types. If a node reaches that limit, we give up
-  /// inferencing on it and give it the dynamic type.
-  final int MAX_CHANGE_COUNT = 6;
-
-  int overallRefineCount = 0;
-  int addedInGraph = 0;
-
-  TypeGraphInferrerEngine(Compiler compiler, this.mainElement)
-        : super(compiler, new TypeInformationSystem(compiler));
-
-  /**
-   * A set of selector names that [List] implements, that we know return
-   * their element type.
-   */
-  final Set<Selector> _returnsListElementTypeSet = new Set<Selector>.from(
-    <Selector>[
-      new Selector.getter('first', null),
-      new Selector.getter('last', null),
-      new Selector.getter('single', null),
-      new Selector.call('singleWhere', null, 1),
-      new Selector.call('elementAt', null, 1),
-      new Selector.index(),
-      new Selector.call('removeAt', null, 1),
-      new Selector.call('removeLast', null, 0)
-    ]);
-
-  bool returnsListElementType(Selector selector) {
-    return (selector.mask != null) &&
-           selector.mask.isContainer &&
-           _returnsListElementTypeSet.contains(selector.asUntyped);
-  }
-
-  bool returnsMapValueType(Selector selector) {
-    return (selector.mask != null) &&
-           selector.mask.isMap &&
-           selector.isIndex;
-  }
-
-  void analyzeListAndEnqueue(ListTypeInformation info) {
-    if (info.analyzed) return;
-    info.analyzed = true;
-
-    ListTracerVisitor tracer = new ListTracerVisitor(info, this);
-    bool succeeded = tracer.run();
-    if (!succeeded) return;
-
-    info.bailedOut = false;
-    info.elementType.inferred = true;
-    TypeMask fixedListType = compiler.typesTask.fixedListType;
-    if (info.originalType.forwardTo == fixedListType) {
-      info.checksGrowable = tracer.callsGrowableMethod;
-    }
-    tracer.assignments.forEach(info.elementType.addAssignment);
-    // Enqueue the list for later refinement
-    workQueue.add(info);
-    workQueue.add(info.elementType);
-  }
-
-  void analyzeMapAndEnqueue(MapTypeInformation info) {
-    if (info.analyzed) return;
-    info.analyzed = true;
-    MapTracerVisitor tracer = new MapTracerVisitor(info, this);
-
-    bool succeeded = tracer.run();
-    if (!succeeded) return;
-
-    info.bailedOut = false;
-    for (int i = 0; i < tracer.keyAssignments.length; ++i) {
-      TypeInformation newType = info.addEntryAssignment(
-          tracer.keyAssignments[i], tracer.valueAssignments[i]);
-      if (newType != null) workQueue.add(newType);
-    }
-    for (TypeInformation map in tracer.mapAssignments) {
-      workQueue.addAll(info.addMapAssignment(map));
-    }
-
-    info.markAsInferred();
-    workQueue.add(info.keyType);
-    workQueue.add(info.valueType);
-    workQueue.addAll(info.typeInfoMap.values);
-    workQueue.add(info);
-  }
-
-  void runOverAllElements() {
-    if (compiler.disableTypeInference) return;
-    if (compiler.verbose) {
-      compiler.progress.reset();
-    }
-    sortResolvedElements().forEach((Element element) {
-      if (compiler.shouldPrintProgress) {
-        compiler.log('Added $addedInGraph elements in inferencing graph.');
-        compiler.progress.reset();
-      }
-      // This also forces the creation of the [ElementTypeInformation] to ensure
-      // it is in the graph.
-      types.withMember(element, () => analyze(element, null));
-    });
-    compiler.log('Added $addedInGraph elements in inferencing graph.');
-
-    buildWorkQueue();
-    refine();
-
-    // Try to infer element types of lists and compute their escape information.
-    types.allocatedLists.values.forEach((ListTypeInformation info) {
-      analyzeListAndEnqueue(info);
-    });
-
-    // Try to infer the key and value types for maps and compute the values'
-    // escape information.
-    types.allocatedMaps.values.forEach((MapTypeInformation info) {
-      analyzeMapAndEnqueue(info);
-    });
-
-    Set<FunctionElement> bailedOutOn = new Set<FunctionElement>();
-
-    // Trace closures to potentially infer argument types.
-    types.allocatedClosures.forEach((info) {
-      void trace(Iterable<FunctionElement> elements,
-                 ClosureTracerVisitor tracer) {
-        tracer.run();
-        if (!tracer.continueAnalyzing) {
-          elements.forEach((FunctionElement e) {
-            compiler.world.registerMightBePassedToApply(e);
-            if (_VERBOSE) print("traced closure $e as ${true} (bail)");
-            e.functionSignature.forEachParameter((parameter) {
-              types.getInferredTypeOf(parameter).giveUp(
-                  this,
-                  clearAssignments: false);
-            });
-          });
-          bailedOutOn.addAll(elements);
-          return;
-        }
-        elements
-            .where((e) => !bailedOutOn.contains(e))
-            .forEach((FunctionElement e) {
-          e.functionSignature.forEachParameter((parameter) {
-            var info = types.getInferredTypeOf(parameter);
-            info.maybeResume();
-            workQueue.add(info);
-          });
-          if (tracer.tracedType.mightBePassedToFunctionApply) {
-            compiler.world.registerMightBePassedToApply(e);
-          };
-          if (_VERBOSE) {
-            print("traced closure $e as "
-                "${compiler.world.getMightBePassedToApply(e)}");
-          }
-        });
-      }
-      if (info is ClosureTypeInformation) {
-        Iterable<FunctionElement> elements = [info.element];
-        trace(elements, new ClosureTracerVisitor(elements, info, this));
-      } else if (info is CallSiteTypeInformation) {
-        // We only are interested in functions here, as other targets
-        // of this closure call are not a root to trace but an intermediate
-        // for some other function.
-        Iterable<FunctionElement> elements = info.callees
-            .where((e) => e.isFunction);
-        trace(elements, new ClosureTracerVisitor(elements, info, this));
-      } else {
-        assert(info is ElementTypeInformation);
-        trace([info.element],
-            new StaticTearOffClosureTracerVisitor(info.element, info, this));
-      }
-    });
-
-    // Reset all nodes that use lists/maps that have been inferred, as well
-    // as nodes that use elements fetched from these lists/maps. The
-    // workset for a new run of the analysis will be these nodes.
-    Set<TypeInformation> seenTypes = new Set<TypeInformation>();
-    while (!workQueue.isEmpty) {
-      TypeInformation info = workQueue.remove();
-      if (seenTypes.contains(info)) continue;
-      // If the node cannot be reset, we do not need to update its users either.
-      if (!info.reset(this)) continue;
-      seenTypes.add(info);
-      workQueue.addAll(info.users);
-    }
-
-    workQueue.addAll(seenTypes);
-    refine();
-
-    if (_PRINT_SUMMARY) {
-      types.allocatedLists.values.forEach((ListTypeInformation info) {
-        print('${info.type} '
-              'for ${info.originalType.allocationNode} '
-              'at ${info.originalType.allocationElement} '
-              'after ${info.refineCount}');
-      });
-      types.allocatedMaps.values.forEach((MapTypeInformation info) {
-        print('${info.type} '
-              'for ${info.originalType.allocationNode} '
-              'at ${info.originalType.allocationElement} '
-              'after ${info.refineCount}');
-      });
-      types.allocatedClosures.forEach((TypeInformation info) {
-        if (info is ElementTypeInformation) {
-          print('${types.getInferredSignatureOf(info.element)} for '
-                '${info.element}');
-        } else if (info is ClosureTypeInformation) {
-          print('${types.getInferredSignatureOf(info.element)} for '
-                '${info.element}');
-        } else if (info is DynamicCallSiteTypeInformation) {
-          for (Element target in info.targets) {
-            if (target is FunctionElement) {
-              print('${types.getInferredSignatureOf(target)} for ${target}');
-            } else {
-              print('${types.getInferredTypeOf(target).type} for ${target}');
-            }
-          }
-        } else {
-          print('${info.type} for some unknown kind of closure');
-        }
-      });
-      analyzedElements.forEach((Element elem) {
-        TypeInformation type = types.getInferredTypeOf(elem);
-        print('${elem} :: ${type} from ${type.assignments} ');
-      });
-    }
-
-    compiler.log('Inferred $overallRefineCount types.');
-
-    processLoopInformation();
-  }
-
-  void analyze(Element element, ArgumentsTypes arguments) {
-    element = element.implementation;
-    if (analyzedElements.contains(element)) return;
-    analyzedElements.add(element);
-
-    SimpleTypeInferrerVisitor visitor =
-        new SimpleTypeInferrerVisitor(element, compiler, this);
-    TypeInformation type;
-    compiler.withCurrentElement(element, () {
-      type = visitor.run();
-    });
-    addedInGraph++;
-
-    if (element.isField) {
-      VariableElement fieldElement = element;
-      ast.Node node = fieldElement.node;
-      if (element.isFinal || element.isConst) {
-        // If [element] is final and has an initializer, we record
-        // the inferred type.
-        if (fieldElement.initializer != null) {
-          if (type is! ListTypeInformation && type is! MapTypeInformation) {
-            // For non-container types, the constant handler does
-            // constant folding that could give more precise results.
-            ConstantExpression constant = compiler.backend.constants
-                .getConstantForVariable(element);
-            if (constant != null) {
-              ConstantValue value = constant.value;
-              if (value.isFunction) {
-                FunctionConstantValue functionConstant = value;
-                type = types.allocateClosure(node, functionConstant.element);
-              } else {
-                // Although we might find a better type, we have to keep
-                // the old type around to ensure that we get a complete view
-                // of the type graph and do not drop any flow edges.
-                TypeMask refinedType = value.computeMask(compiler);
-                assert(TypeMask.assertIsNormalized(refinedType, classWorld));
-                type = new NarrowTypeInformation(type, refinedType);
-                types.allocatedTypes.add(type);
-              }
-            }
-          }
-          recordType(element, type);
-        } else if (!element.isInstanceMember) {
-          recordType(element, types.nullType);
-        }
-      } else if (fieldElement.initializer == null) {
-        // Only update types of static fields if there is no
-        // assignment. Instance fields are dealt with in the constructor.
-        if (Elements.isStaticOrTopLevelField(element)) {
-          recordTypeOfNonFinalField(node, element, type);
-        }
-      } else {
-        recordTypeOfNonFinalField(node, element, type);
-      }
-      if (Elements.isStaticOrTopLevelField(element) &&
-          fieldElement.initializer != null &&
-          !element.isConst) {
-        var argument = fieldElement.initializer;
-        // TODO(13429): We could do better here by using the
-        // constant handler to figure out if it's a lazy field or not.
-        if (argument.asSend() != null ||
-            (argument.asNewExpression() != null && !argument.isConst)) {
-          recordType(element, types.nullType);
-        }
-      }
-    } else {
-      recordReturnType(element, type);
-    }
-  }
-
-  void processLoopInformation() {
-    allocatedCalls.forEach((info) {
-      if (!info.inLoop) return;
-      if (info is StaticCallSiteTypeInformation) {
-        compiler.world.addFunctionCalledInLoop(info.calledElement);
-      } else if (info.selector.mask != null &&
-                 !info.selector.mask.containsAll(compiler.world)) {
-        // For instance methods, we only register a selector called in a
-        // loop if it is a typed selector, to avoid marking too many
-        // methods as being called from within a loop. This cuts down
-        // on the code bloat.
-        info.targets.forEach(compiler.world.addFunctionCalledInLoop);
-      }
-    });
-  }
-
-  void refine() {
-    while (!workQueue.isEmpty) {
-      if (compiler.shouldPrintProgress) {
-        compiler.log('Inferred $overallRefineCount types.');
-        compiler.progress.reset();
-      }
-      TypeInformation info = workQueue.remove();
-      TypeMask oldType = info.type;
-      TypeMask newType = info.refine(this);
-      // Check that refinement has not accidentially changed the type.
-      assert(oldType == info.type);
-      if (info.abandonInferencing) info.doNotEnqueue = true;
-      if ((info.type = newType) != oldType) {
-        overallRefineCount++;
-        info.refineCount++;
-        if (info.refineCount > MAX_CHANGE_COUNT) {
-          if (_ANOMALY_WARN) {
-            print("ANOMALY WARNING: max refinement reached for $info");
-          }
-          info.giveUp(this);
-          info.type = info.refine(this);
-          info.doNotEnqueue = true;
-        }
-        workQueue.addAll(info.users);
-        if (info.hasStableType(this)) {
-          info.stabilize(this);
-        }
-      }
-    }
-  }
-
-  void buildWorkQueue() {
-    workQueue.addAll(types.typeInformations.values);
-    workQueue.addAll(types.allocatedTypes);
-    workQueue.addAll(types.allocatedClosures);
-    workQueue.addAll(allocatedCalls);
-  }
-
-  /**
-   * Update the assignments to parameters in the graph. [remove] tells
-   * wheter assignments must be added or removed. If [init] is false,
-   * parameters are added to the work queue.
-   */
-  void updateParameterAssignments(TypeInformation caller,
-                                  Element callee,
-                                  ArgumentsTypes arguments,
-                                  Selector selector,
-                                  {bool remove, bool addToQueue: true}) {
-    if (callee.name == Compiler.NO_SUCH_METHOD) return;
-    if (callee.isField) {
-      if (selector.isSetter) {
-        ElementTypeInformation info = types.getInferredTypeOf(callee);
-        if (remove) {
-          info.removeAssignment(arguments.positional[0]);
-        } else {
-          info.addAssignment(arguments.positional[0]);
-        }
-        if (addToQueue) workQueue.add(info);
-      }
-    } else if (callee.isGetter) {
-      return;
-    } else if (selector != null && selector.isGetter) {
-      // We are tearing a function off and thus create a closure.
-      assert(callee.isFunction);
-      MemberTypeInformation info = types.getInferredTypeOf(callee);
-      if (remove) {
-        info.closurizedCount--;
-      } else {
-        info.closurizedCount++;
-        if (Elements.isStaticOrTopLevel(callee)) {
-          types.allocatedClosures.add(info);
-        } else {
-          // We add the call-site type information here so that we
-          // can benefit from further refinement of the selector.
-          types.allocatedClosures.add(caller);
-        }
-        FunctionElement function = callee.implementation;
-        FunctionSignature signature = function.functionSignature;
-        signature.forEachParameter((Element parameter) {
-          ParameterTypeInformation info = types.getInferredTypeOf(parameter);
-          info.tagAsTearOffClosureParameter(this);
-          if (addToQueue) workQueue.add(info);
-        });
-      }
-    } else {
-      FunctionElement function = callee.implementation;
-      FunctionSignature signature = function.functionSignature;
-      int parameterIndex = 0;
-      bool visitingRequiredParameter = true;
-      signature.forEachParameter((Element parameter) {
-        if (signature.hasOptionalParameters &&
-            parameter == signature.firstOptionalParameter) {
-          visitingRequiredParameter = false;
-        }
-        TypeInformation type = visitingRequiredParameter
-            ? arguments.positional[parameterIndex]
-            : signature.optionalParametersAreNamed
-              ? arguments.named[parameter.name]
-              : parameterIndex < arguments.positional.length
-                  ? arguments.positional[parameterIndex]
-                  : null;
-        if (type == null) type = getDefaultTypeOfParameter(parameter);
-        TypeInformation info = types.getInferredTypeOf(parameter);
-        if (remove) {
-          info.removeAssignment(type);
-        } else {
-          info.addAssignment(type);
-        }
-        parameterIndex++;
-        if (addToQueue) workQueue.add(info);
-      });
-    }
-  }
-
-  /**
-   * Sets the type of a parameter's default value to [type]. If the global
-   * mapping in [defaultTypeOfParameter] already contains a type, it must be
-   * a [PlaceholderTypeInformation], which will be replaced. All its uses are
-   * updated.
-   */
-  void setDefaultTypeOfParameter(ParameterElement parameter,
-                                 TypeInformation type) {
-    assert(parameter.functionDeclaration.isImplementation);
-    TypeInformation existing = defaultTypeOfParameter[parameter];
-    defaultTypeOfParameter[parameter] = type;
-    TypeInformation info = types.getInferredTypeOf(parameter);
-    if (existing != null && existing is PlaceholderTypeInformation) {
-      // Replace references to [existing] to use [type] instead.
-      if (parameter.functionDeclaration.isInstanceMember) {
-        ParameterAssignments assignments = info.assignments;
-        assignments.replace(existing, type);
-        type.addUser(info);
-      } else {
-        List<TypeInformation> assignments = info.assignments;
-        for (int i = 0; i < assignments.length; i++) {
-          if (assignments[i] == existing) {
-            assignments[i] = type;
-            type.addUser(info);
-          }
-        }
-      }
-    } else {
-      assert(existing == null);
-    }
-  }
-
-  /**
-   * Returns the [TypeInformation] node for the default value of a parameter.
-   * If this is queried before it is set by [setDefaultTypeOfParameter], a
-   * [PlaceholderTypeInformation] is returned, which will later be replaced
-   * by the actual node when [setDefaultTypeOfParameter] is called.
-   *
-   * Invariant: After graph construction, no [PlaceholderTypeInformation] nodes
-   *            should be present and a default type for each parameter should
-   *            exist.
-   */
-  TypeInformation getDefaultTypeOfParameter(Element parameter) {
-    return defaultTypeOfParameter.putIfAbsent(parameter, () {
-      return new PlaceholderTypeInformation(types.currentMember);
-    });
-  }
-
-  /**
-   * Helper to inspect the [TypeGraphInferrer]'s state. To be removed by
-   * TODO(johnniwinther) once synthetic parameters get their own default
-   * values.
-   */
-  bool hasAlreadyComputedTypeOfParameterDefault(Element parameter) {
-    TypeInformation seen = defaultTypeOfParameter[parameter];
-    return (seen != null && seen is! PlaceholderTypeInformation);
-  }
-
-  TypeInformation typeOfElement(Element element) {
-    if (element is FunctionElement) return types.functionType;
-    return types.getInferredTypeOf(element);
-  }
-
-  TypeInformation returnTypeOfElement(Element element) {
-    if (element is !FunctionElement) return types.dynamicType;
-    return types.getInferredTypeOf(element);
-  }
-
-  void recordTypeOfFinalField(Spannable node,
-                              Element analyzed,
-                              Element element,
-                              TypeInformation type) {
-    types.getInferredTypeOf(element).addAssignment(type);
-  }
-
-  void recordTypeOfNonFinalField(Spannable node,
-                                 Element element,
-                                 TypeInformation type) {
-    types.getInferredTypeOf(element).addAssignment(type);
-  }
-
-  void recordType(Element element, TypeInformation type) {
-    types.getInferredTypeOf(element).addAssignment(type);
-  }
-
-  void recordReturnType(Element element, TypeInformation type) {
-    TypeInformation info = types.getInferredTypeOf(element);
-    if (element.name == '==') {
-      // Even if x.== doesn't return a bool, 'x == null' evaluates to 'false'.
-      info.addAssignment(types.boolType);
-    }
-    // TODO(ngeoffray): Clean up. We do these checks because
-    // [SimpleTypesInferrer] deals with two different inferrers.
-    if (type == null) return;
-    if (info.assignments.isEmpty) info.addAssignment(type);
-  }
-
-  TypeInformation addReturnTypeFor(Element element,
-                                   TypeInformation unused,
-                                   TypeInformation newType) {
-    TypeInformation type = types.getInferredTypeOf(element);
-    // TODO(ngeoffray): Clean up. We do this check because
-    // [SimpleTypesInferrer] deals with two different inferrers.
-    if (element.isGenerativeConstructor) return type;
-    type.addAssignment(newType);
-    return type;
-  }
-
-  TypeInformation registerCalledElement(Spannable node,
-                                        Selector selector,
-                                        Element caller,
-                                        Element callee,
-                                        ArgumentsTypes arguments,
-                                        SideEffects sideEffects,
-                                        bool inLoop) {
-    CallSiteTypeInformation info = new StaticCallSiteTypeInformation(
-          types.currentMember, node, caller, callee, selector, arguments,
-          inLoop);
-    info.addToGraph(this);
-    allocatedCalls.add(info);
-    updateSideEffects(sideEffects, selector, callee);
-    return info;
-  }
-
-  TypeInformation registerCalledSelector(ast.Node node,
-                                         Selector selector,
-                                         TypeInformation receiverType,
-                                         Element caller,
-                                         ArgumentsTypes arguments,
-                                         SideEffects sideEffects,
-                                         bool inLoop) {
-    if (selector.isClosureCall) {
-      return registerCalledClosure(
-          node, selector, receiverType, caller, arguments, sideEffects, inLoop);
-    }
-
-    compiler.world.allFunctions.filter(selector).forEach((callee) {
-      updateSideEffects(sideEffects, selector, callee);
-    });
-
-    CallSiteTypeInformation info = new DynamicCallSiteTypeInformation(
-          types.currentMember, node, caller, selector, receiverType, arguments,
-          inLoop);
-
-    info.addToGraph(this);
-    allocatedCalls.add(info);
-    return info;
-  }
-
-  TypeInformation registerCalledClosure(ast.Node node,
-                                        Selector selector,
-                                        TypeInformation closure,
-                                        Element caller,
-                                        ArgumentsTypes arguments,
-                                        SideEffects sideEffects,
-                                        bool inLoop) {
-    sideEffects.setDependsOnSomething();
-    sideEffects.setAllSideEffects();
-    CallSiteTypeInformation info = new ClosureCallSiteTypeInformation(
-          types.currentMember, node, caller, selector, closure, arguments,
-          inLoop);
-    info.addToGraph(this);
-    allocatedCalls.add(info);
-    return info;
-  }
-
-  // Sorts the resolved elements by size. We do this for this inferrer
-  // to get the same results for [ListTracer] compared to the
-  // [SimpleTypesInferrer].
-  Iterable<Element> sortResolvedElements() {
-    int max = 0;
-    Map<int, Setlet<Element>> methodSizes = new Map<int, Setlet<Element>>();
-    compiler.enqueuer.resolution.resolvedElements.forEach((AstElement element) {
-        // TODO(ngeoffray): Not sure why the resolver would put a null
-        // mapping.
-        if (!compiler.enqueuer.resolution.hasBeenResolved(element)) return;
-        TreeElementMapping mapping = element.resolvedAst.elements;
-        element = element.implementation;
-        if (element.impliesType) return;
-        assert(invariant(element,
-            element.isField ||
-            element.isFunction ||
-            element.isGenerativeConstructor ||
-            element.isGetter ||
-            element.isSetter,
-            message: 'Unexpected element kind: ${element.kind}'));
-        if (element.isAbstract) return;
-        // Put the other operators in buckets by length, later to be added in
-        // length order.
-        int length = mapping.getSelectorCount();
-        max = length > max ? length : max;
-        Setlet<Element> set = methodSizes.putIfAbsent(
-            length, () => new Setlet<Element>());
-        set.add(element);
-    });
-
-    List<Element> result = <Element>[];
-    for (int i = 0; i <= max; i++) {
-      Setlet<Element> set = methodSizes[i];
-      if (set != null) result.addAll(set);
-    }
-    return result;
-  }
-
-  void clear() {
-    allocatedCalls.clear();
-    defaultTypeOfParameter.clear();
-    types.typeInformations.values.forEach((info) => info.clear());
-    types.allocatedTypes.clear();
-    types.concreteTypes.clear();
-    types.allocatedClosures.clear();
-    analyzedElements.clear();
-    generativeConstructorsExposingThis.clear();
-  }
-
-  Iterable<Element> getCallersOf(Element element) {
-    if (compiler.disableTypeInference) {
-      throw new UnsupportedError(
-          "Cannot query the type inferrer when type inference is disabled.");
-    }
-    MemberTypeInformation info = types.getInferredTypeOf(element);
-    return info.callers;
-  }
-
-  /**
-   * Returns the type of [element] when being called with [selector].
-   */
-  TypeInformation typeOfElementWithSelector(Element element,
-                                            Selector selector) {
-    if (element.name == Compiler.NO_SUCH_METHOD &&
-        selector.name != element.name) {
-      // An invocation can resolve to a [noSuchMethod], in which case
-      // we get the return type of [noSuchMethod].
-      return returnTypeOfElement(element);
-    } else if (selector.isGetter) {
-      if (element.isFunction) {
-        // [functionType] is null if the inferrer did not run.
-        return types.functionType == null
-            ? types.dynamicType
-            : types.functionType;
-      } else if (element.isField) {
-        return typeOfElement(element);
-      } else if (Elements.isUnresolved(element)) {
-        return types.dynamicType;
-      } else {
-        assert(element.isGetter);
-        return returnTypeOfElement(element);
-      }
-    } else if (element.isGetter || element.isField) {
-      assert(selector.isCall || selector.isSetter);
-      return types.dynamicType;
-    } else {
-      return returnTypeOfElement(element);
-    }
-  }
-
-  void recordCapturedLocalRead(Local local) {}
-
-  void recordLocalUpdate(Local local, TypeInformation type) {}
-}
-
-class TypeGraphInferrer implements TypesInferrer {
-  TypeGraphInferrerEngine inferrer;
-  final Compiler compiler;
-  TypeGraphInferrer(Compiler this.compiler);
-
-  String get name => 'Graph inferrer';
-
-  void analyzeMain(Element main) {
-    inferrer = new TypeGraphInferrerEngine(compiler, main);
-    inferrer.runOverAllElements();
-  }
-
-  TypeMask getReturnTypeOfElement(Element element) {
-    if (compiler.disableTypeInference) return compiler.typesTask.dynamicType;
-    // Currently, closure calls return dynamic.
-    if (element is! FunctionElement) return compiler.typesTask.dynamicType;
-    return inferrer.types.getInferredTypeOf(element).type;
-  }
-
-  TypeMask getTypeOfElement(Element element) {
-    if (compiler.disableTypeInference) return compiler.typesTask.dynamicType;
-    // The inferrer stores the return type for a function, so we have to
-    // be careful to not return it here.
-    if (element is FunctionElement) return compiler.typesTask.functionType;
-    return inferrer.types.getInferredTypeOf(element).type;
-  }
-
-  TypeMask getTypeOfNode(Element owner, ast.Node node) {
-    if (compiler.disableTypeInference) return compiler.typesTask.dynamicType;
-    return inferrer.types.allocatedLists[node].type;
-  }
-
-  bool isFixedArrayCheckedForGrowable(ast.Node node) {
-    if (compiler.disableTypeInference) return true;
-    ListTypeInformation info = inferrer.types.allocatedLists[node];
-    return info.checksGrowable;
-  }
-
-  TypeMask getTypeOfSelector(Selector selector) {
-    if (compiler.disableTypeInference) return compiler.typesTask.dynamicType;
-    // Bailout for closure calls. We're not tracking types of
-    // closures.
-    if (selector.isClosureCall) return compiler.typesTask.dynamicType;
-    if (selector.isSetter || selector.isIndexSet) {
-      return compiler.typesTask.dynamicType;
-    }
-    if (inferrer.returnsListElementType(selector)) {
-      ContainerTypeMask mask = selector.mask;
-      TypeMask elementType = mask.elementType;
-      return elementType == null ? compiler.typesTask.dynamicType : elementType;
-    }
-    if (inferrer.returnsMapValueType(selector)) {
-      MapTypeMask mask = selector.mask;
-      TypeMask valueType = mask.valueType;
-      return valueType == null ? compiler.typesTask.dynamicType
-                               : valueType;
-    }
-
-    TypeMask result = const TypeMask.nonNullEmpty();
-    Iterable<Element> elements = compiler.world.allFunctions.filter(selector);
-    for (Element element in elements) {
-      TypeMask type =
-          inferrer.typeOfElementWithSelector(element, selector).type;
-      result = result.union(type, compiler.world);
-    }
-    return result;
-  }
-
-  Iterable<Element> getCallersOf(Element element) {
-    if (compiler.disableTypeInference) {
-      throw new UnsupportedError(
-          "Cannot query the type inferrer when type inference is disabled.");
-    }
-    return inferrer.getCallersOf(element);
-  }
-
-  bool isCalledOnce(Element element) {
-    if (compiler.disableTypeInference) return false;
-    MemberTypeInformation info = inferrer.types.getInferredTypeOf(element);
-    return info.isCalledOnce();
-  }
-
-  void clear() {
-    inferrer.clear();
-  }
-}