Move public API for elements into a public location

pkg/analyzer/lib/dart/element/element.dart

+// Copyright (c) 2014, 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 analyzer.dart.element.element;
+
+import 'package:analyzer/dart/element/type.dart';
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/constant.dart' show DartObject;
+import 'package:analyzer/src/generated/engine.dart' show AnalysisContext;
+import 'package:analyzer/src/generated/java_core.dart';
+import 'package:analyzer/src/generated/java_engine.dart';
+import 'package:analyzer/src/generated/resolver.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/generated/utilities_dart.dart';
+import 'package:analyzer/src/task/dart.dart';
+import 'package:analyzer/task/model.dart' show AnalysisTarget;
+
+/**
+ * An element that represents a class.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class ClassElement
+    implements TypeDefiningElement, TypeParameterizedElement {
+  /**
+   * An empty list of class elements.
+   */
+  static const List<ClassElement> EMPTY_LIST = const <ClassElement>[];
+
+  /**
+   * Return a list containing all of the accessors (getters and setters)
+   * declared in this class.
+   */
+  List<PropertyAccessorElement> get accessors;
+
+  /**
+   * Return a list containing all the supertypes defined for this class and its
+   * supertypes. This includes superclasses, mixins and interfaces.
+   */
+  List<InterfaceType> get allSupertypes;
+
+  /**
+   * Return a list containing all of the constructors declared in this class.
+   */
+  List<ConstructorElement> get constructors;
+
+  /**
+   * Return a list containing all of the fields declared in this class.
+   */
+  List<FieldElement> get fields;
+
+  /**
+   * Return `true` if this class or its superclass declares a non-final instance
+   * field.
+   */
+  bool get hasNonFinalField;
+
+  /**
+   * Return `true` if this class has reference to super (so, for example, cannot
+   * be used as a mixin).
+   */
+  bool get hasReferenceToSuper;
+
+  /**
+   * Return `true` if this class declares a static member.
+   */
+  bool get hasStaticMember;
+
+  /**
+   * Return a list containing all of the interfaces that are implemented by this
+   * class.
+   *
+   * <b>Note:</b> Because the element model represents the state of the code, it
+   * is possible for it to be semantically invalid. In particular, it is not
+   * safe to assume that the inheritance structure of a class does not contain a
+   * cycle. Clients that traverse the inheritance structure must explicitly
+   * guard against infinite loops.
+   */
+  List<InterfaceType> get interfaces;
+
+  /**
+   * Return `true` if this class is abstract. A class is abstract if it has an
+   * explicit `abstract` modifier. Note, that this definition of <i>abstract</i>
+   * is different from <i>has unimplemented members</i>.
+   */
+  bool get isAbstract;
+
+  /**
+   * Return `true` if this class is defined by an enum declaration.
+   */
+  bool get isEnum;
+
+  /**
+   * Return `true` if this class is a mixin application.  A class is a mixin
+   * application if it was declared using the syntax "class A = B with C;".
+   */
+  bool get isMixinApplication;
+
+  /**
+   * Return `true` if this class [isProxy], or if it inherits the proxy
+   * annotation from a supertype.
+   */
+  bool get isOrInheritsProxy;
+
+  /**
+   * Return `true` if this element has an annotation of the form '@proxy'.
+   */
+  bool get isProxy;
+
+  /**
+   * Return `true` if this class can validly be used as a mixin when defining
+   * another class. The behavior of this method is defined by the Dart Language
+   * Specification in section 9:
+   * <blockquote>
+   * It is a compile-time error if a declared or derived mixin refers to super.
+   * It is a compile-time error if a declared or derived mixin explicitly
+   * declares a constructor. It is a compile-time error if a mixin is derived
+   * from a class whose superclass is not Object.
+   * </blockquote>
+   */
+  bool get isValidMixin;
+
+  /**
+   * Return a list containing all of the methods declared in this class.
+   */
+  List<MethodElement> get methods;
+
+  /**
+   * Return a list containing all of the mixins that are applied to the class
+   * being extended in order to derive the superclass of this class.
+   *
+   * <b>Note:</b> Because the element model represents the state of the code, it
+   * is possible for it to be semantically invalid. In particular, it is not
+   * safe to assume that the inheritance structure of a class does not contain a
+   * cycle. Clients that traverse the inheritance structure must explicitly
+   * guard against infinite loops.
+   */
+  List<InterfaceType> get mixins;
+
+  /**
+   * Return the superclass of this class, or `null` if the class represents the
+   * class 'Object'. All other classes will have a non-`null` superclass. If the
+   * superclass was not explicitly declared then the implicit superclass
+   * 'Object' will be returned.
+   *
+   * <b>Note:</b> Because the element model represents the state of the code, it
+   * is possible for it to be semantically invalid. In particular, it is not
+   * safe to assume that the inheritance structure of a class does not contain a
+   * cycle. Clients that traverse the inheritance structure must explicitly
+   * guard against infinite loops.
+   */
+  InterfaceType get supertype;
+
+  @override
+  InterfaceType get type;
+
+  /**
+   * Return the unnamed constructor declared in this class, or `null` if this
+   * class does not declare an unnamed constructor but does declare named
+   * constructors. The returned constructor will be synthetic if this class does
+   * not declare any constructors, in which case it will represent the default
+   * constructor for the class.
+   */
+  ConstructorElement get unnamedConstructor;
+
+  @override
+  NamedCompilationUnitMember computeNode();
+
+  /**
+   * Return the field (synthetic or explicit) defined in this class that has the
+   * given [name], or `null` if this class does not define a field with the
+   * given name.
+   */
+  FieldElement getField(String name);
+
+  /**
+   * Return the element representing the getter with the given [name] that is
+   * declared in this class, or `null` if this class does not declare a getter
+   * with the given name.
+   */
+  PropertyAccessorElement getGetter(String name);
+
+  /**
+   * Return the element representing the method with the given [name] that is
+   * declared in this class, or `null` if this class does not declare a method
+   * with the given name.
+   */
+  MethodElement getMethod(String name);
+
+  /**
+   * Return the named constructor declared in this class with the given [name],
+   * or `null` if this class does not declare a named constructor with the given
+   * name.
+   */
+  ConstructorElement getNamedConstructor(String name);
+
+  /**
+   * Return the element representing the setter with the given [name] that is
+   * declared in this class, or `null` if this class does not declare a setter
+   * with the given name.
+   */
+  PropertyAccessorElement getSetter(String name);
+
+  /**
+   * Determine whether the given [constructor], which exists in the superclass
+   * of this class, is accessible to constructors in this class.
+   */
+  bool isSuperConstructorAccessible(ConstructorElement constructor);
+
+  /**
+   * Return the element representing the method that results from looking up the
+   * given [methodName] in this class with respect to the given [library],
+   * ignoring abstract methods, or `null` if the look up fails. The behavior of
+   * this method is defined by the Dart Language Specification in section
+   * 16.15.1:
+   * <blockquote>
+   * The result of looking up method <i>m</i> in class <i>C</i> with respect to
+   * library <i>L</i> is: If <i>C</i> declares an instance method named <i>m</i>
+   * that is accessible to <i>L</i>, then that method is the result of the
+   * lookup. Otherwise, if <i>C</i> has a superclass <i>S</i>, then the result
+   * of the lookup is the result of looking up method <i>m</i> in <i>S</i> with
+   * respect to <i>L</i>. Otherwise, we say that the lookup has failed.
+   * </blockquote>
+   */
+  MethodElement lookUpConcreteMethod(String methodName, LibraryElement library);
+
+  /**
+   * Return the element representing the getter that results from looking up the
+   * given [getterName] in this class with respect to the given [library], or
+   * `null` if the look up fails. The behavior of this method is defined by the
+   * Dart Language Specification in section 16.15.2:
+   * <blockquote>
+   * The result of looking up getter (respectively setter) <i>m</i> in class
+   * <i>C</i> with respect to library <i>L</i> is: If <i>C</i> declares an
+   * instance getter (respectively setter) named <i>m</i> that is accessible to
+   * <i>L</i>, then that getter (respectively setter) is the result of the
+   * lookup. Otherwise, if <i>C</i> has a superclass <i>S</i>, then the result
+   * of the lookup is the result of looking up getter (respectively setter)
+   * <i>m</i> in <i>S</i> with respect to <i>L</i>. Otherwise, we say that the
+   * lookup has failed.
+   * </blockquote>
+   */
+  PropertyAccessorElement lookUpGetter(
+      String getterName, LibraryElement library);
+
+  /**
+   * Return the element representing the getter that results from looking up the
+   * given [getterName] in the superclass of this class with respect to the
+   * given [library], ignoring abstract getters, or `null` if the look up fails.
+   * The behavior of this method is defined by the Dart Language Specification
+   * in section 16.15.2:
+   * <blockquote>
+   * The result of looking up getter (respectively setter) <i>m</i> in class
+   * <i>C</i> with respect to library <i>L</i> is: If <i>C</i> declares an
+   * instance getter (respectively setter) named <i>m</i> that is accessible to
+   * <i>L</i>, then that getter (respectively setter) is the result of the
+   * lookup. Otherwise, if <i>C</i> has a superclass <i>S</i>, then the result
+   * of the lookup is the result of looking up getter (respectively setter)
+   * <i>m</i> in <i>S</i> with respect to <i>L</i>. Otherwise, we say that the
+   * lookup has failed.
+   * </blockquote>
+   */
+  PropertyAccessorElement lookUpInheritedConcreteGetter(
+      String getterName, LibraryElement library);
+
+  /**
+   * Return the element representing the method that results from looking up the
+   * given [methodName] in the superclass of this class with respect to the
+   * given [library], ignoring abstract methods, or `null` if the look up fails.
+   * The behavior of this method is defined by the Dart Language Specification
+   * in section 16.15.1:
+   * <blockquote>
+   * The result of looking up method <i>m</i> in class <i>C</i> with respect to
+   * library <i>L</i> is:  If <i>C</i> declares an instance method named
+   * <i>m</i> that is accessible to <i>L</i>, then that method is the result of
+   * the lookup. Otherwise, if <i>C</i> has a superclass <i>S</i>, then the
+   * result of the lookup is the result of looking up method <i>m</i> in
+   * <i>S</i> with respect to <i>L</i>. Otherwise, we say that the lookup has
+   * failed.
+   * </blockquote>
+   */
+  MethodElement lookUpInheritedConcreteMethod(
+      String methodName, LibraryElement library);
+
+  /**
+   * Return the element representing the setter that results from looking up the
+   * given [setterName] in the superclass of this class with respect to the
+   * given [library], ignoring abstract setters, or `null` if the look up fails.
+   * The behavior of this method is defined by the Dart Language Specification
+   * in section 16.15.2:
+   * <blockquote>
+   * The result of looking up getter (respectively setter) <i>m</i> in class
+   * <i>C</i> with respect to library <i>L</i> is:  If <i>C</i> declares an
+   * instance getter (respectively setter) named <i>m</i> that is accessible to
+   * <i>L</i>, then that getter (respectively setter) is the result of the
+   * lookup. Otherwise, if <i>C</i> has a superclass <i>S</i>, then the result
+   * of the lookup is the result of looking up getter (respectively setter)
+   * <i>m</i> in <i>S</i> with respect to <i>L</i>. Otherwise, we say that the
+   * lookup has failed.
+   * </blockquote>
+   */
+  PropertyAccessorElement lookUpInheritedConcreteSetter(
+      String setterName, LibraryElement library);
+
+  /**
+   * Return the element representing the method that results from looking up the
+   * given [methodName] in the superclass of this class with respect to the
+   * given [library], or `null` if the look up fails. The behavior of this
+   * method is defined by the Dart Language Specification in section 16.15.1:
+   * <blockquote>
+   * The result of looking up method <i>m</i> in class <i>C</i> with respect to
+   * library <i>L</i> is:  If <i>C</i> declares an instance method named
+   * <i>m</i> that is accessible to <i>L</i>, then that method is the result of
+   * the lookup. Otherwise, if <i>C</i> has a superclass <i>S</i>, then the
+   * result of the lookup is the result of looking up method <i>m</i> in
+   * <i>S</i> with respect to <i>L</i>. Otherwise, we say that the lookup has
+   * failed.
+   * </blockquote>
+   */
+  MethodElement lookUpInheritedMethod(
+      String methodName, LibraryElement library);
+
+  /**
+   * Return the element representing the method that results from looking up the
+   * given [methodName] in this class with respect to the given [library], or
+   * `null` if the look up fails. The behavior of this method is defined by the
+   * Dart Language Specification in section 16.15.1:
+   * <blockquote>
+   * The result of looking up method <i>m</i> in class <i>C</i> with respect to
+   * library <i>L</i> is:  If <i>C</i> declares an instance method named
+   * <i>m</i> that is accessible to <i>L</i>, then that method is the result of
+   * the lookup. Otherwise, if <i>C</i> has a superclass <i>S</i>, then the
+   * result of the lookup is the result of looking up method <i>m</i> in
+   * <i>S</i> with respect to <i>L</i>. Otherwise, we say that the lookup has
+   * failed.
+   * </blockquote>
+   */
+  MethodElement lookUpMethod(String methodName, LibraryElement library);
+
+  /**
+   * Return the element representing the setter that results from looking up the
+   * given [setterName] in this class with respect to the given [library], or
+   * `null` if the look up fails. The behavior of this method is defined by the
+   * Dart Language Specification in section 16.15.2:
+   * <blockquote>
+   * The result of looking up getter (respectively setter) <i>m</i> in class
+   * <i>C</i> with respect to library <i>L</i> is: If <i>C</i> declares an
+   * instance getter (respectively setter) named <i>m</i> that is accessible to
+   * <i>L</i>, then that getter (respectively setter) is the result of the
+   * lookup. Otherwise, if <i>C</i> has a superclass <i>S</i>, then the result
+   * of the lookup is the result of looking up getter (respectively setter)
+   * <i>m</i> in <i>S</i> with respect to <i>L</i>. Otherwise, we say that the
+   * lookup has failed.
+   * </blockquote>
+   */
+  PropertyAccessorElement lookUpSetter(
+      String setterName, LibraryElement library);
+}
+
+/**
+ * An element that is contained within a [ClassElement].
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class ClassMemberElement implements Element {
+  @override
+  ClassElement get enclosingElement;
+
+  /**
+   * Return `true` if this element is a static element. A static element is an
+   * element that is not associated with a particular instance, but rather with
+   * an entire library or class.
+   */
+  bool get isStatic;
+}
+
+/**
+ * An element representing a compilation unit.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class CompilationUnitElement implements Element, UriReferencedElement {
+  /**
+   * An empty list of compilation unit elements.
+   */
+  static const List<CompilationUnitElement> EMPTY_LIST =
+      const <CompilationUnitElement>[];
+
+  /**
+   * Return a list containing all of the top-level accessors (getters and
+   * setters) contained in this compilation unit.
+   */
+  List<PropertyAccessorElement> get accessors;
+
+  @override
+  LibraryElement get enclosingElement;
+
+  /**
+   * Return a list containing all of the enums contained in this compilation
+   * unit.
+   */
+  List<ClassElement> get enums;
+
+  /**
+   * Return a list containing all of the top-level functions contained in this
+   * compilation unit.
+   */
+  List<FunctionElement> get functions;
+
+  /**
+   * Return a list containing all of the function type aliases contained in this
+   * compilation unit.
+   */
+  List<FunctionTypeAliasElement> get functionTypeAliases;
+
+  /**
+   * Return `true` if this compilation unit defines a top-level function named
+   * `loadLibrary`.
+   */
+  bool get hasLoadLibraryFunction;
+
+  /**
+   * Return a list containing all of the top-level variables contained in this
+   * compilation unit.
+   */
+  List<TopLevelVariableElement> get topLevelVariables;
+
+  /**
+   * Return a list containing all of the classes contained in this compilation
+   * unit.
+   */
+  List<ClassElement> get types;
+
+  @override
+  CompilationUnit computeNode();
+
+  /**
+   * Return the element at the given [offset], maybe `null` if no such element.
+   */
+  Element getElementAt(int offset);
+
+  /**
+   * Return the enum defined in this compilation unit that has the given [name],
+   * or `null` if this compilation unit does not define an enum with the given
+   * name.
+   */
+  ClassElement getEnum(String name);
+
+  /**
+   * Return the class defined in this compilation unit that has the given
+   * [name], or `null` if this compilation unit does not define a class with the
+   * given name.
+   */
+  ClassElement getType(String name);
+}
+
+/**
+ * An element representing a constructor or a factory method defined within a
+ * class.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class ConstructorElement
+    implements ClassMemberElement, ExecutableElement, ConstantEvaluationTarget {
+  /**
+   * An empty list of constructor elements.
+   */
+  static const List<ConstructorElement> EMPTY_LIST =
+      const <ConstructorElement>[];
+
+  /**
+   * Return `true` if this constructor is a const constructor.
+   */
+  bool get isConst;
+
+  /**
+   * Return `true` if this constructor can be used as a default constructor -
+   * unnamed and has no required parameters.
+   */
+  bool get isDefaultConstructor;
+
+  /**
+   * Return `true` if this constructor represents a factory constructor.
+   */
+  bool get isFactory;
+
+  /**
+   * Return the offset of the character immediately following the last character
+   * of this constructor's name, or `null` if not named.
+   */
+  int get nameEnd;
+
+  /**
+   * Return the offset of the `.` before this constructor name, or `null` if
+   * not named.
+   */
+  int get periodOffset;
+
+  /**
+   * Return the constructor to which this constructor is redirecting, or `null`
+   * if this constructor does not redirect to another constructor or if the
+   * library containing this constructor has not yet been resolved.
+   */
+  ConstructorElement get redirectedConstructor;
+
+  @override
+  ConstructorDeclaration computeNode();
+}
+
+/**
+ * The base class for all of the elements in the element model. Generally
+ * speaking, the element model is a semantic model of the program that
+ * represents things that are declared with a name and hence can be referenced
+ * elsewhere in the code.
+ *
+ * There are two exceptions to the general case. First, there are elements in
+ * the element model that are created for the convenience of various kinds of
+ * analysis but that do not have any corresponding declaration within the source
+ * code. Such elements are marked as being <i>synthetic</i>. Examples of
+ * synthetic elements include
+ * * default constructors in classes that do not define any explicit
+ *   constructors,
+ * * getters and setters that are induced by explicit field declarations,
+ * * fields that are induced by explicit declarations of getters and setters,
+ *   and
+ * * functions representing the initialization expression for a variable.
+ *
+ * Second, there are elements in the element model that do not have a name.
+ * These correspond to unnamed functions and exist in order to more accurately
+ * represent the semantic structure of the program.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class Element implements AnalysisTarget {
+  /**
+   * A comparator that can be used to sort elements by their name offset.
+   * Elements with a smaller offset will be sorted to be before elements with a
+   * larger name offset.
+   */
+  static final Comparator<Element> SORT_BY_OFFSET =
+      (Element firstElement, Element secondElement) =>
+          firstElement.nameOffset - secondElement.nameOffset;
+
+  /**
+   * Return the analysis context in which this element is defined.
+   */
+  AnalysisContext get context;
+
+  /**
+   * Return the display name of this element, or `null` if this element does not
+   * have a name.
+   *
+   * In most cases the name and the display name are the same. Differences
+   * though are cases such as setters where the name of some setter `set f(x)`
+   * is `f=`, instead of `f`.
+   */
+  String get displayName;
+
+  /**
+   * Return the source range of the documentation comment for this element,
+   * or `null` if this element does not or cannot have a documentation.
+   */
+  SourceRange get docRange;
+
+  /**
+   * Return the element that either physically or logically encloses this
+   * element. This will be `null` if this element is a library because libraries
+   * are the top-level elements in the model.
+   */
+  Element get enclosingElement;
+
+  /**
+   * The unique integer identifier of this element.
+   */
+  int get id;
+
+  /**
+   * Return `true` if this element has an annotation of the form '@deprecated'
+   * or '@Deprecated('..')'.
+   */
+  bool get isDeprecated;
+
+  /**
+   * Return `true` if this element has an annotation of the form '@override'.
+   */
+  bool get isOverride;
+
+  /**
+   * Return `true` if this element is private. Private elements are visible only
+   * within the library in which they are declared.
+   */
+  bool get isPrivate;
+
+  /**
+   * Return `true` if this element is public. Public elements are visible within
+   * any library that imports the library in which they are declared.
+   */
+  bool get isPublic;
+
+  /**
+   * Return `true` if this element is synthetic. A synthetic element is an
+   * element that is not represented in the source code explicitly, but is
+   * implied by the source code, such as the default constructor for a class
+   * that does not explicitly define any constructors.
+   */
+  bool get isSynthetic;
+
+  /**
+   * Return the kind of element that this is.
+   */
+  ElementKind get kind;
+
+  /**
+   * Return the library that contains this element. This will be the element
+   * itself if it is a library element. This will be `null` if this element is
+   * an HTML file because HTML files are not contained in libraries.
+   */
+  LibraryElement get library;
+
+  /**
+   * Return an object representing the location of this element in the element
+   * model. The object can be used to locate this element at a later time.
+   */
+  ElementLocation get location;
+
+  /**
+   * Return a list containing all of the metadata associated with this element.
+   * The array will be empty if the element does not have any metadata or if the
+   * library containing this element has not yet been resolved.
+   */
+  List<ElementAnnotation> get metadata;
+
+  /**
+   * Return the name of this element, or `null` if this element does not have a
+   * name.
+   */
+  String get name;
+
+  /**
+   * Return the length of the name of this element in the file that contains the
+   * declaration of this element, or `0` if this element does not have a name.
+   */
+  int get nameLength;
+
+  /**
+   * Return the offset of the name of this element in the file that contains the
+   * declaration of this element, or `-1` if this element is synthetic, does not
+   * have a name, or otherwise does not have an offset.
+   */
+  int get nameOffset;
+
+  @override
+  Source get source;
+
+  /**
+   * Return the resolved [CompilationUnit] that declares this element, or `null`
+   * if this element is synthetic.
+   *
+   * This method is expensive, because resolved AST might have been already
+   * evicted from cache, so parsing and resolving will be performed.
+   */
+  CompilationUnit get unit;
+
+  /**
+   * Use the given [visitor] to visit this element. Return the value returned by
+   * the visitor as a result of visiting this element.
+   */
+  accept(ElementVisitor visitor);
+
+  /**
+   * Return the documentation comment for this element as it appears in the
+   * original source (complete with the beginning and ending delimiters), or
+   * `null` if this element does not have a documentation comment associated
+   * with it. This can be a long-running operation if the information needed to
+   * access the comment is not cached.
+   *
+   * Throws [AnalysisException] if the documentation comment could not be
+   * determined because the analysis could not be performed
+   */
+  String computeDocumentationComment();
+
+  /**
+   * Return the resolved [AstNode] node that declares this element, or `null` if
+   * this element is synthetic or isn't contained in a compilation unit, such as
+   * a [LibraryElement].
+   *
+   * This method is expensive, because resolved AST might be evicted from cache,
+   * so parsing and resolving will be performed.
+   *
+   * <b>Note:</b> This method cannot be used in an async environment.
+   */
+  AstNode computeNode();
+
+  /**
+   * Return the most immediate ancestor of this element for which the
+   * [predicate] returns `true`, or `null` if there is no such ancestor. Note
+   * that this element will never be returned.
+   */
+  Element getAncestor(Predicate<Element> predicate);
+
+  /**
+   * Return a display name for the given element that includes the path to the
+   * compilation unit in which the type is defined. If [shortName] is `null`
+   * then [getDisplayName] will be used as the name of this element. Otherwise
+   * the provided name will be used.
+   */
+  // TODO(brianwilkerson) Make the parameter optional.
+  String getExtendedDisplayName(String shortName);
+
+  /**
+   * Return `true` if this element, assuming that it is within scope, is
+   * accessible to code in the given [library]. This is defined by the Dart
+   * Language Specification in section 3.2:
+   * <blockquote>
+   * A declaration <i>m</i> is accessible to library <i>L</i> if <i>m</i> is
+   * declared in <i>L</i> or if <i>m</i> is public.
+   * </blockquote>
+   */
+  bool isAccessibleIn(LibraryElement library);
+
+  /**
+   * Use the given [visitor] to visit all of the children of this element. There
+   * is no guarantee of the order in which the children will be visited.
+   */
+  void visitChildren(ElementVisitor visitor);
+}
+
+/**
+ * A single annotation associated with an element.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class ElementAnnotation {
+  /**
+   * An empty list of annotations.
+   */
+  static const List<ElementAnnotation> EMPTY_LIST = const <ElementAnnotation>[];
+
+  /**
+   * Return a representation of the value of this annotation.
+   *
+   * Return `null` if the value of this annotation could not be computed because
+   * of errors.
+   */
+  DartObject get constantValue;
+
+  /**
+   * Return the element representing the field, variable, or const constructor
+   * being used as an annotation.
+   */
+  Element get element;
+
+  /**
+   * Return `true` if this annotation marks the associated element as being
+   * deprecated.
+   */
+  bool get isDeprecated;
+
+  /**
+   * Return `true` if this annotation marks the associated method as being
+   * expected to override an inherited method.
+   */
+  bool get isOverride;
+
+  /**
+   * Return `true` if this annotation marks the associated class as implementing
+   * a proxy object.
+   */
+  bool get isProxy;
+}
+
+/**
+ * The enumeration `ElementKind` defines the various kinds of elements in the
+ * element model.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+class ElementKind extends Enum<ElementKind> {
+  static const ElementKind CLASS = const ElementKind('CLASS', 0, "class");
+
+  static const ElementKind COMPILATION_UNIT =
+      const ElementKind('COMPILATION_UNIT', 1, "compilation unit");
+
+  static const ElementKind CONSTRUCTOR =
+      const ElementKind('CONSTRUCTOR', 2, "constructor");
+
+  static const ElementKind DYNAMIC =
+      const ElementKind('DYNAMIC', 3, "<dynamic>");
+
+  static const ElementKind ERROR = const ElementKind('ERROR', 4, "<error>");
+
+  static const ElementKind EXPORT =
+      const ElementKind('EXPORT', 5, "export directive");
+
+  static const ElementKind FIELD = const ElementKind('FIELD', 6, "field");
+
+  static const ElementKind FUNCTION =
+      const ElementKind('FUNCTION', 7, "function");
+
+  static const ElementKind GETTER = const ElementKind('GETTER', 8, "getter");
+
+  static const ElementKind IMPORT =
+      const ElementKind('IMPORT', 9, "import directive");
+
+  static const ElementKind LABEL = const ElementKind('LABEL', 10, "label");
+
+  static const ElementKind LIBRARY =
+      const ElementKind('LIBRARY', 11, "library");
+
+  static const ElementKind LOCAL_VARIABLE =
+      const ElementKind('LOCAL_VARIABLE', 12, "local variable");
+
+  static const ElementKind METHOD = const ElementKind('METHOD', 13, "method");
+
+  static const ElementKind NAME = const ElementKind('NAME', 14, "<name>");
+
+  static const ElementKind PARAMETER =
+      const ElementKind('PARAMETER', 15, "parameter");
+
+  static const ElementKind PREFIX =
+      const ElementKind('PREFIX', 16, "import prefix");
+
+  static const ElementKind SETTER = const ElementKind('SETTER', 17, "setter");
+
+  static const ElementKind TOP_LEVEL_VARIABLE =
+      const ElementKind('TOP_LEVEL_VARIABLE', 18, "top level variable");
+
+  static const ElementKind FUNCTION_TYPE_ALIAS =
+      const ElementKind('FUNCTION_TYPE_ALIAS', 19, "function type alias");
+
+  static const ElementKind TYPE_PARAMETER =
+      const ElementKind('TYPE_PARAMETER', 20, "type parameter");
+
+  static const ElementKind UNIVERSE =
+      const ElementKind('UNIVERSE', 21, "<universe>");
+
+  static const List<ElementKind> values = const [
+    CLASS,
+    COMPILATION_UNIT,
+    CONSTRUCTOR,
+    DYNAMIC,
+    ERROR,
+    EXPORT,
+    FIELD,
+    FUNCTION,
+    GETTER,
+    IMPORT,
+    LABEL,
+    LIBRARY,
+    LOCAL_VARIABLE,
+    METHOD,
+    NAME,
+    PARAMETER,
+    PREFIX,
+    SETTER,
+    TOP_LEVEL_VARIABLE,
+    FUNCTION_TYPE_ALIAS,
+    TYPE_PARAMETER,
+    UNIVERSE
+  ];
+
+  /**
+   * The name displayed in the UI for this kind of element.
+   */
+  final String displayName;
+
+  /**
+   * Initialize a newly created element kind to have the given [displayName].
+   */
+  const ElementKind(String name, int ordinal, this.displayName)
+      : super(name, ordinal);
+
+  /**
+   * Return the kind of the given [element], or [ERROR] if the element is
+   * `null`. This is a utility method that can reduce the need for null checks
+   * in other places.
+   */
+  static ElementKind of(Element element) {
+    if (element == null) {
+      return ERROR;
+    }
+    return element.kind;
+  }
+}
+
+/**
+ * The location of an element within the element model.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class ElementLocation {
+  /**
+   * Return the path to the element whose location is represented by this
+   * object. Clients must not modify the returned array.
+   */
+  List<String> get components;
+
+  /**
+   * Return an encoded representation of this location that can be used to
+   * create a location that is equal to this location.
+   */
+  String get encoding;
+}
+
+/**
+ * An object that can be used to visit an element structure.
+ *
+ * Clients may implement this class.
+ */
+abstract class ElementVisitor<R> {
+  R visitClassElement(ClassElement element);
+
+  R visitCompilationUnitElement(CompilationUnitElement element);
+
+  R visitConstructorElement(ConstructorElement element);
+
+  R visitExportElement(ExportElement element);
+
+  R visitFieldElement(FieldElement element);
+
+  R visitFieldFormalParameterElement(FieldFormalParameterElement element);
+
+  R visitFunctionElement(FunctionElement element);
+
+  R visitFunctionTypeAliasElement(FunctionTypeAliasElement element);
+
+  R visitImportElement(ImportElement element);
+
+  R visitLabelElement(LabelElement element);
+
+  R visitLibraryElement(LibraryElement element);
+
+  R visitLocalVariableElement(LocalVariableElement element);
+
+  R visitMethodElement(MethodElement element);
+
+  R visitMultiplyDefinedElement(MultiplyDefinedElement element);
+
+  R visitParameterElement(ParameterElement element);
+
+  R visitPrefixElement(PrefixElement element);
+
+  R visitPropertyAccessorElement(PropertyAccessorElement element);
+
+  R visitTopLevelVariableElement(TopLevelVariableElement element);
+
+  R visitTypeParameterElement(TypeParameterElement element);
+}
+
+/**
+ * An element representing an executable object, including functions, methods,
+ * constructors, getters, and setters.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class ExecutableElement implements FunctionTypedElement {
+  /**
+   * An empty list of executable elements.
+   */
+  static const List<ExecutableElement> EMPTY_LIST = const <ExecutableElement>[];
+
+  /**
+   * Return a list containing all of the functions defined within this
+   * executable element.
+   */
+  List<FunctionElement> get functions;
+
+  /**
+   * Return `true` if this executable element did not have an explicit return
+   * type specified for it in the original source. Note that if there was no
+   * explicit return type, and if the element model is fully populated, then
+   * the [returnType] will not be `null`.
+   */
+  bool get hasImplicitReturnType;
+
+  /**
+   * Return `true` if this executable element is abstract. Executable elements
+   * are abstract if they are not external and have no body.
+   */
+  bool get isAbstract;
+
+  /**
+   * Return `true` if this executable element has body marked as being
+   * asynchronous.
+   */
+  bool get isAsynchronous;
+
+  /**
+   * Return `true` if this executable element is external. Executable elements
+   * are external if they are explicitly marked as such using the 'external'
+   * keyword.
+   */
+  bool get isExternal;
+
+  /**
+   * Return `true` if this executable element has a body marked as being a
+   * generator.
+   */
+  bool get isGenerator;
+
+  /**
+   * Return `true` if this executable element is an operator. The test may be
+   * based on the name of the executable element, in which case the result will
+   * be correct when the name is legal.
+   */
+  bool get isOperator;
+
+  /**
+   * Return `true` if this element is a static element. A static element is an
+   * element that is not associated with a particular instance, but rather with
+   * an entire library or class.
+   */
+  bool get isStatic;
+
+  /**
+   * Return `true` if this executable element has a body marked as being
+   * synchronous.
+   */
+  bool get isSynchronous;
+
+  /**
+   * Return a list containing all of the labels defined within this executable
+   * element.
+   */
+  List<LabelElement> get labels;
+
+  /**
+   * Return a list containing all of the local variables defined within this
+   * executable element.
+   */
+  List<LocalVariableElement> get localVariables;
+}
+
+/**
+ * An export directive within a library.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class ExportElement implements Element, UriReferencedElement {
+  /**
+   * An empty list of export elements.
+   */
+  static const List<ExportElement> EMPTY_LIST = const <ExportElement>[];
+
+  /**
+   * Return a list containing the combinators that were specified as part of the
+   * export directive in the order in which they were specified.
+   */
+  List<NamespaceCombinator> get combinators;
+
+  /**
+   * Return the library that is exported from this library by this export
+   * directive.
+   */
+  LibraryElement get exportedLibrary;
+}
+
+/**
+ * A field defined within a type.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class FieldElement
+    implements ClassMemberElement, PropertyInducingElement {
+  /**
+   * An empty list of field elements.
+   */
+  static const List<FieldElement> EMPTY_LIST = const <FieldElement>[];
+
+  /**
+   * Return {@code true} if this element is an enum constant.
+   */
+  bool get isEnumConstant;
+
+  @override
+  AstNode computeNode();
+}
+
+/**
+ * A field formal parameter defined within a constructor element.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class FieldFormalParameterElement implements ParameterElement {
+  /**
+   * Return the field element associated with this field formal parameter, or
+   * `null` if the parameter references a field that doesn't exist.
+   */
+  FieldElement get field;
+}
+
+/**
+ * A (non-method) function. This can be either a top-level function, a local
+ * function, a closure, or the initialization expression for a field or
+ * variable.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class FunctionElement implements ExecutableElement, LocalElement {
+  /**
+   * An empty list of function elements.
+   */
+  static const List<FunctionElement> EMPTY_LIST = const <FunctionElement>[];
+
+  /**
+   * The name of the method that can be implemented by a class to allow its
+   * instances to be invoked as if they were a function.
+   */
+  static final String CALL_METHOD_NAME = "call";
+
+  /**
+   * The name of the synthetic function defined for libraries that are deferred.
+   */
+  static final String LOAD_LIBRARY_NAME = "loadLibrary";
+
+  /**
+   * The name of the function used as an entry point.
+   */
+  static const String MAIN_FUNCTION_NAME = "main";
+
+  /**
+   * The name of the method that will be invoked if an attempt is made to invoke
+   * an undefined method on an object.
+   */
+  static final String NO_SUCH_METHOD_METHOD_NAME = "noSuchMethod";
+
+  /**
+   * Return `true` if the function is an entry point, i.e. a top-level function
+   * and has the name `main`.
+   */
+  bool get isEntryPoint;
+
+  @override
+  FunctionDeclaration computeNode();
+}
+
+/**
+ * A function type alias (`typedef`).
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class FunctionTypeAliasElement implements FunctionTypedElement {
+  /**
+   * An empty array of type alias elements.
+   */
+  static List<FunctionTypeAliasElement> EMPTY_LIST =
+      new List<FunctionTypeAliasElement>(0);
+
+  /**
+   * Return the compilation unit in which this type alias is defined.
+   */
+  @override
+  CompilationUnitElement get enclosingElement;
+
+  @override
+  FunctionTypeAlias computeNode();
+}
+
+/**
+ * An element that has a [FunctionType] as its [type].
+ *
+ * This also provides convenient access to the parameters and return type.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class FunctionTypedElement
+    implements TypeDefiningElement, TypeParameterizedElement {
+  /**
+   * Return a list containing all of the parameters defined by this executable
+   * element.
+   */
+  List<ParameterElement> get parameters;
+
+  /**
+   * Return the return type defined by this element. If the element model is
+   * fully populated, then the [returnType] will not be `null`, even if no
+   * return type was explicitly specified.
+   */
+  DartType get returnType;
+
+  @override
+  FunctionType get type;
+}
+
+/**
+ * A combinator that causes some of the names in a namespace to be hidden when
+ * being imported.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class HideElementCombinator implements NamespaceCombinator {
+  /**
+   * Return a list containing the names that are not to be made visible in the
+   * importing library even if they are defined in the imported library.
+   */
+  List<String> get hiddenNames;
+}
+
+/**
+ * A single import directive within a library.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class ImportElement implements Element, UriReferencedElement {
+  /**
+   * An empty list of import elements.
+   */
+  static const List<ImportElement> EMPTY_LIST = const <ImportElement>[];
+
+  /**
+   * Return a list containing the combinators that were specified as part of the
+   * import directive in the order in which they were specified.
+   */
+  List<NamespaceCombinator> get combinators;
+
+  /**
+   * Return the library that is imported into this library by this import
+   * directive.
+   */
+  LibraryElement get importedLibrary;
+
+  /**
+   * Return `true` if this import is for a deferred library.
+   */
+  bool get isDeferred;
+
+  /**
+   * Return the prefix that was specified as part of the import directive, or
+   * `null` if there was no prefix specified.
+   */
+  PrefixElement get prefix;
+
+  /**
+   * Return the offset of the prefix of this import in the file that contains
+   * this import directive, or `-1` if this import is synthetic, does not have a
+   * prefix, or otherwise does not have an offset.
+   */
+  int get prefixOffset;
+}
+
+/**
+ * A label associated with a statement.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class LabelElement implements Element {
+  /**
+   * An empty list of label elements.
+   */
+  static const List<LabelElement> EMPTY_LIST = const <LabelElement>[];
+
+  @override
+  ExecutableElement get enclosingElement;
+}
+
+/**
+ * A library.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class LibraryElement implements Element {
+  /**
+   * An empty list of library elements.
+   */
+  static const List<LibraryElement> EMPTY_LIST = const <LibraryElement>[];
+
+  /**
+   * Return the compilation unit that defines this library.
+   */
+  CompilationUnitElement get definingCompilationUnit;
+
+  /**
+   * Return the entry point for this library, or `null` if this library does not
+   * have an entry point. The entry point is defined to be a zero argument
+   * top-level function whose name is `main`.
+   */
+  FunctionElement get entryPoint;
+
+  /**
+   * Return a list containing all of the libraries that are exported from this
+   * library.
+   */
+  List<LibraryElement> get exportedLibraries;
+
+  /**
+   * The export [Namespace] of this library, `null` if it has not been
+   * computed yet.
+   */
+  Namespace get exportNamespace;
+
+  /**
+   * Return a list containing all of the exports defined in this library.
+   */
+  List<ExportElement> get exports;
+
+  /**
+   * Return `true` if the defining compilation unit of this library contains at
+   * least one import directive whose URI uses the "dart-ext" scheme.
+   */
+  bool get hasExtUri;
+
+  /**
+   * Return `true` if this library defines a top-level function named
+   * `loadLibrary`.
+   */
+  bool get hasLoadLibraryFunction;
+
+  /**
+   * Return a list containing all of the libraries that are imported into this
+   * library. This includes all of the libraries that are imported using a
+   * prefix (also available through the prefixes returned by [getPrefixes]) and
+   * those that are imported without a prefix.
+   */
+  List<LibraryElement> get importedLibraries;
+
+  /**
+   * Return a list containing all of the imports defined in this library.
+   */
+  List<ImportElement> get imports;
+
+  /**
+   * Return `true` if this library is an application that can be run in the
+   * browser.
+   */
+  bool get isBrowserApplication;
+
+  /**
+   * Return `true` if this library is the dart:core library.
+   */
+  bool get isDartCore;
+
+  /**
+   * Return `true` if this library is part of the SDK.
+   */
+  bool get isInSdk;
+
+  /**
+   * Return the element representing the synthetic function `loadLibrary` that
+   * is implicitly defined for this library if the library is imported using a
+   * deferred import.
+   */
+  FunctionElement get loadLibraryFunction;
+
+  /**
+   * Return a list containing all of the compilation units that are included in
+   * this library using a `part` directive. This does not include the defining
+   * compilation unit that contains the `part` directives.
+   */
+  List<CompilationUnitElement> get parts;
+
+  /**
+   * Return a list containing elements for each of the prefixes used to `import`
+   * libraries into this library. Each prefix can be used in more than one
+   * `import` directive.
+   */
+  List<PrefixElement> get prefixes;
+
+  /**
+   * The public [Namespace] of this library, `null` if it has not been
+   * computed yet.
+   */
+  Namespace get publicNamespace;
+
+  /**
+   * Return a list containing all of the compilation units this library consists
+   * of. This includes the defining compilation unit and units included using
+   * the `part` directive.
+   */
+  List<CompilationUnitElement> get units;
+
+  /**
+   * Return a list containing all directly and indirectly imported libraries.
+   */
+  List<LibraryElement> get visibleLibraries;
+
+  /**
+   * Return a list containing all of the imports that share the given [prefix],
+   * or an empty array if there are no such imports.
+   */
+  List<ImportElement> getImportsWithPrefix(PrefixElement prefix);
+
+  /**
+   * Return the class defined in this library that has the given [name], or
+   * `null` if this library does not define a class with the given name.
+   */
+  ClassElement getType(String className);
+
+  /**
+   * Return `true` if this library is up to date with respect to the given
+   * [timeStamp]. If any transitively referenced Source is newer than the time
+   * stamp, this method returns false.
+   */
+  bool isUpToDate(int timeStamp);
+}
+
+/**
+ * An element that can be (but is not required to be) defined within a method
+ * or function (an [ExecutableElement]).
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class LocalElement implements Element {
+  /**
+   * Return a source range that covers the approximate portion of the source in
+   * which the name of this element is visible, or `null` if there is no single
+   * range of characters within which the element name is visible.
+   *
+   * * For a local variable, this includes everything from the end of the
+   *   variable's initializer to the end of the block that encloses the variable
+   *   declaration.
+   * * For a parameter, this includes the body of the method or function that
+   *   declares the parameter.
+   * * For a local function, this includes everything from the beginning of the
+   *   function's body to the end of the block that encloses the function
+   *   declaration.
+   * * For top-level functions, `null` will be returned because they are
+   *   potentially visible in multiple sources.
+   */
+  SourceRange get visibleRange;
+}
+
+/**
+ * A local variable.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class LocalVariableElement implements LocalElement, VariableElement {
+  /**
+   * An empty list of field elements.
+   */
+  static const List<LocalVariableElement> EMPTY_LIST =
+      const <LocalVariableElement>[];
+}
+
+/**
+ * An element that represents a method defined within a type.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class MethodElement implements ClassMemberElement, ExecutableElement {
+  /**
+   * An empty list of method elements.
+   */
+  static const List<MethodElement> EMPTY_LIST = const <MethodElement>[];
+
+  @override
+  MethodDeclaration computeNode();
+}
+
+/**
+ * The enumeration `Modifier` defines constants for all of the modifiers defined
+ * by the Dart language and for a few additional flags that are useful.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+class Modifier extends Enum<Modifier> {
+  /**
+   * Indicates that the modifier 'abstract' was applied to the element.
+   */
+  static const Modifier ABSTRACT = const Modifier('ABSTRACT', 0);
+
+  /**
+   * Indicates that an executable element has a body marked as being
+   * asynchronous.
+   */
+  static const Modifier ASYNCHRONOUS = const Modifier('ASYNCHRONOUS', 1);
+
+  /**
+   * Indicates that the modifier 'const' was applied to the element.
+   */
+  static const Modifier CONST = const Modifier('CONST', 2);
+
+  /**
+   * Indicates that the import element represents a deferred library.
+   */
+  static const Modifier DEFERRED = const Modifier('DEFERRED', 3);
+
+  /**
+   * Indicates that a class element was defined by an enum declaration.
+   */
+  static const Modifier ENUM = const Modifier('ENUM', 4);
+
+  /**
+   * Indicates that a class element was defined by an enum declaration.
+   */
+  static const Modifier EXTERNAL = const Modifier('EXTERNAL', 5);
+
+  /**
+   * Indicates that the modifier 'factory' was applied to the element.
+   */
+  static const Modifier FACTORY = const Modifier('FACTORY', 6);
+
+  /**
+   * Indicates that the modifier 'final' was applied to the element.
+   */
+  static const Modifier FINAL = const Modifier('FINAL', 7);
+
+  /**
+   * Indicates that an executable element has a body marked as being a
+   * generator.
+   */
+  static const Modifier GENERATOR = const Modifier('GENERATOR', 8);
+
+  /**
+   * Indicates that the pseudo-modifier 'get' was applied to the element.
+   */
+  static const Modifier GETTER = const Modifier('GETTER', 9);
+
+  /**
+   * A flag used for libraries indicating that the defining compilation unit
+   * contains at least one import directive whose URI uses the "dart-ext"
+   * scheme.
+   */
+  static const Modifier HAS_EXT_URI = const Modifier('HAS_EXT_URI', 10);
+
+  /**
+   * Indicates that the associated element did not have an explicit type
+   * associated with it. If the element is an [ExecutableElement], then the
+   * type being referred to is the return type.
+   */
+  static const Modifier IMPLICIT_TYPE = const Modifier('IMPLICIT_TYPE', 11);
+
+  /**
+   * Indicates that a class can validly be used as a mixin.
+   */
+  static const Modifier MIXIN = const Modifier('MIXIN', 12);
+
+  /**
+   * Indicates that a class is a mixin application.
+   */
+  static const Modifier MIXIN_APPLICATION =
+      const Modifier('MIXIN_APPLICATION', 13);
+
+  /**
+   * Indicates that the value of a parameter or local variable might be mutated
+   * within the context.
+   */
+  static const Modifier POTENTIALLY_MUTATED_IN_CONTEXT =
+      const Modifier('POTENTIALLY_MUTATED_IN_CONTEXT', 14);
+
+  /**
+   * Indicates that the value of a parameter or local variable might be mutated
+   * within the scope.
+   */
+  static const Modifier POTENTIALLY_MUTATED_IN_SCOPE =
+      const Modifier('POTENTIALLY_MUTATED_IN_SCOPE', 15);
+
+  /**
+   * Indicates that a class contains an explicit reference to 'super'.
+   */
+  static const Modifier REFERENCES_SUPER =
+      const Modifier('REFERENCES_SUPER', 16);
+
+  /**
+   * Indicates that the pseudo-modifier 'set' was applied to the element.
+   */
+  static const Modifier SETTER = const Modifier('SETTER', 17);
+
+  /**
+   * Indicates that the modifier 'static' was applied to the element.
+   */
+  static const Modifier STATIC = const Modifier('STATIC', 18);
+
+  /**
+   * Indicates that the element does not appear in the source code but was
+   * implicitly created. For example, if a class does not define any
+   * constructors, an implicit zero-argument constructor will be created and it
+   * will be marked as being synthetic.
+   */
+  static const Modifier SYNTHETIC = const Modifier('SYNTHETIC', 19);
+
+  static const List<Modifier> values = const [
+    ABSTRACT,
+    ASYNCHRONOUS,
+    CONST,
+    DEFERRED,
+    ENUM,
+    EXTERNAL,
+    FACTORY,
+    FINAL,
+    GENERATOR,
+    GETTER,
+    HAS_EXT_URI,
+    IMPLICIT_TYPE,
+    MIXIN,
+    MIXIN_APPLICATION,
+    POTENTIALLY_MUTATED_IN_CONTEXT,
+    POTENTIALLY_MUTATED_IN_SCOPE,
+    REFERENCES_SUPER,
+    SETTER,
+    STATIC,
+    SYNTHETIC
+  ];
+
+  const Modifier(String name, int ordinal) : super(name, ordinal);
+}
+
+/**
+ * A pseudo-element that represents multiple elements defined within a single
+ * scope that have the same name. This situation is not allowed by the language,
+ * so objects implementing this interface always represent an error. As a
+ * result, most of the normal operations on elements do not make sense and will
+ * return useless results.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class MultiplyDefinedElement implements Element {
+  /**
+   * Return a list containing all of the elements that were defined within the
+   * scope to have the same name.
+   */
+  List<Element> get conflictingElements;
+
+  /**
+   * Return the type of this element as the dynamic type.
+   */
+  DartType get type;
+}
+
+/**
+ * An [ExecutableElement], with the additional information of a list of
+ * [ExecutableElement]s from which this element was composed.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class MultiplyInheritedExecutableElement implements ExecutableElement {
+  /**
+   * Return a list containing all of the executable elements defined within this
+   * executable element.
+   */
+  List<ExecutableElement> get inheritedElements;
+}
+
+/**
+ * An object that controls how namespaces are combined.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class NamespaceCombinator {
+  /**
+   * An empty list of namespace combinators.
+   */
+  static const List<NamespaceCombinator> EMPTY_LIST =
+      const <NamespaceCombinator>[];
+}
+
+/**
+ * A parameter defined within an executable element.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class ParameterElement
+    implements LocalElement, VariableElement, ConstantEvaluationTarget {
+  /**
+   * An empty list of parameter elements.
+   */
+  static const List<ParameterElement> EMPTY_LIST = const <ParameterElement>[];
+
+  /**
+   * Return the Dart code of the default value, or `null` if no default value.
+   */
+  String get defaultValueCode;
+
+  /**
+   * Return `true` if this parameter is an initializing formal parameter.
+   */
+  bool get isInitializingFormal;
+
+  /**
+   * Return the kind of this parameter.
+   */
+  ParameterKind get parameterKind;
+
+  /**
+   * Return a list containing all of the parameters defined by this parameter.
+   * A parameter will only define other parameters if it is a function typed
+   * parameter.
+   */
+  List<ParameterElement> get parameters;
+
+  /**
+   * Return a list containing all of the type parameters defined by this
+   * parameter. A parameter will only define other parameters if it is a
+   * function typed parameter.
+   */
+  List<TypeParameterElement> get typeParameters;
+
+  /**
+   * Append the type, name and possibly the default value of this parameter to
+   * the given [buffer].
+   */
+  void appendToWithoutDelimiters(StringBuffer buffer);
+
+  @override
+  FormalParameter computeNode();
+}
+
+/**
+ * A prefix used to import one or more libraries into another library.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class PrefixElement implements Element {
+  /**
+   * An empty list of prefix elements.
+   */
+  static const List<PrefixElement> EMPTY_LIST = const <PrefixElement>[];
+
+  @override
+  LibraryElement get enclosingElement;
+
+  /**
+   * Return a list containing all of the libraries that are imported using this
+   * prefix.
+   */
+  List<LibraryElement> get importedLibraries;
+}
+
+/**
+ * A getter or a setter. Note that explicitly defined property accessors
+ * implicitly define a synthetic field. Symmetrically, synthetic accessors are
+ * implicitly created for explicitly defined fields. The following rules apply:
+ *
+ * * Every explicit field is represented by a non-synthetic [FieldElement].
+ * * Every explicit field induces a getter and possibly a setter, both of which
+ *   are represented by synthetic [PropertyAccessorElement]s.
+ * * Every explicit getter or setter is represented by a non-synthetic
+ *   [PropertyAccessorElement].
+ * * Every explicit getter or setter (or pair thereof if they have the same
+ *   name) induces a field that is represented by a synthetic [FieldElement].
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class PropertyAccessorElement implements ExecutableElement {
+  /**
+   * An empty list of property accessor elements.
+   */
+  static const List<PropertyAccessorElement> EMPTY_LIST =
+      const <PropertyAccessorElement>[];
+
+  /**
+   * Return the accessor representing the getter that corresponds to (has the
+   * same name as) this setter, or `null` if this accessor is not a setter or if
+   * there is no corresponding getter.
+   */
+  PropertyAccessorElement get correspondingGetter;
+
+  /**
+   * Return the accessor representing the setter that corresponds to (has the
+   * same name as) this getter, or `null` if this accessor is not a getter or if
+   * there is no corresponding setter.
+   */
+  PropertyAccessorElement get correspondingSetter;
+
+  /**
+   * Return `true` if this accessor represents a getter.
+   */
+  bool get isGetter;
+
+  /**
+   * Return `true` if this accessor represents a setter.
+   */
+  bool get isSetter;
+
+  /**
+   * Return the field or top-level variable associated with this accessor. If
+   * this accessor was explicitly defined (is not synthetic) then the variable
+   * associated with it will be synthetic.
+   */
+  PropertyInducingElement get variable;
+}
+
+/**
+ * A variable that has an associated getter and possibly a setter. Note that
+ * explicitly defined variables implicitly define a synthetic getter and that
+ * non-`final` explicitly defined variables implicitly define a synthetic
+ * setter. Symmetrically, synthetic fields are implicitly created for explicitly
+ * defined getters and setters. The following rules apply:
+ *
+ * * Every explicit variable is represented by a non-synthetic
+ *   [PropertyInducingElement].
+ * * Every explicit variable induces a getter and possibly a setter, both of
+ *   which are represented by synthetic [PropertyAccessorElement]s.
+ * * Every explicit getter or setter is represented by a non-synthetic
+ *   [PropertyAccessorElement].
+ * * Every explicit getter or setter (or pair thereof if they have the same
+ *   name) induces a variable that is represented by a synthetic
+ *   [PropertyInducingElement].
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class PropertyInducingElement implements VariableElement {
+  /**
+   * An empty list of elements.
+   */
+  static const List<PropertyInducingElement> EMPTY_LIST =
+      const <PropertyInducingElement>[];
+
+  /**
+   * Return the getter associated with this variable. If this variable was
+   * explicitly defined (is not synthetic) then the getter associated with it
+   * will be synthetic.
+   */
+  PropertyAccessorElement get getter;
+
+  /**
+   * Return the propagated type of this variable, or `null` if type propagation
+   * has not been performed, for example because the variable is not final.
+   */
+  DartType get propagatedType;
+
+  /**
+   * Return the setter associated with this variable, or `null` if the variable
+   * is effectively `final` and therefore does not have a setter associated with
+   * it. (This can happen either because the variable is explicitly defined as
+   * being `final` or because the variable is induced by an explicit getter that
+   * does not have a corresponding setter.) If this variable was explicitly
+   * defined (is not synthetic) then the setter associated with it will be
+   * synthetic.
+   */
+  PropertyAccessorElement get setter;
+}
+
+/**
+ * A combinator that cause some of the names in a namespace to be visible (and
+ * the rest hidden) when being imported.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class ShowElementCombinator implements NamespaceCombinator {
+  /**
+   * Return the offset of the character immediately following the last character
+   * of this node.
+   */
+  int get end;
+
+  /**
+   * Return the offset of the 'show' keyword of this element.
+   */
+  int get offset;
+
+  /**
+   * Return a list containing the names that are to be made visible in the
+   * importing library if they are defined in the imported library.
+   */
+  List<String> get shownNames;
+}
+
+/**
+ * A top-level variable.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class TopLevelVariableElement implements PropertyInducingElement {
+  /**
+   * An empty list of top-level variable elements.
+   */
+  static const List<TopLevelVariableElement> EMPTY_LIST =
+      const <TopLevelVariableElement>[];
+
+  @override
+  VariableDeclaration computeNode();
+}
+
+/**
+ * An element that defines a type.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class TypeDefiningElement implements Element {
+  /**
+   * Return the type defined by this element.
+   */
+  DartType get type;
+}
+
+/**
+ * A type parameter.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class TypeParameterElement implements TypeDefiningElement {
+  /**
+   * An empty list of type parameter elements.
+   */
+  static const List<TypeParameterElement> EMPTY_LIST =
+      const <TypeParameterElement>[];
+
+  /**
+   * Return the type representing the bound associated with this parameter, or
+   * `null` if this parameter does not have an explicit bound.
+   */
+  DartType get bound;
+
+  @override
+  TypeParameterType get type;
+}
+
+/**
+ * An element that has type parameters, such as a class or a typedef. This also
+ * includes functions and methods if support for generic methods is enabled.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class TypeParameterizedElement implements Element {
+  /**
+   * Return a list containing all of the type parameters declared by this
+   * element directly. This does not include type parameters that are declared
+   * by any enclosing elements.
+   */
+  List<TypeParameterElement> get typeParameters;
+}
+
+/**
+ * A pseudo-elements that represents names that are undefined. This situation is
+ * not allowed by the language, so objects implementing this interface always
+ * represent an error. As a result, most of the normal operations on elements do
+ * not make sense and will return useless results.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class UndefinedElement implements Element {}
+
+/**
+ * An element included into a library using some URI.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class UriReferencedElement implements Element {
+  /**
+   * Return the URI that is used to include this element into the enclosing
+   * library, or `null` if this is the defining compilation unit of a library.
+   */
+  String get uri;
+
+  /**
+   * Return the offset of the character immediately following the last character
+   * of this node's URI, or `-1` for synthetic import.
+   */
+  int get uriEnd;
+
+  /**
+   * Return the offset of the URI in the file, or `-1` if this element is
+   * synthetic.
+   */
+  int get uriOffset;
+}
+
+/**
+ * A variable. There are more specific subclasses for more specific kinds of
+ * variables.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class VariableElement implements Element, ConstantEvaluationTarget {
+  /**
+   * An empty list of variable elements.
+   */
+  static const List<VariableElement> EMPTY_LIST = const <VariableElement>[];
+
+  /**
+   * Return a representation of the value of this variable.
+   *
+   * Return `null` if either this variable was not declared with the 'const'
+   * modifier or if the value of this variable could not be computed because of
+   * errors.
+   */
+  DartObject get constantValue;
+
+  /**
+   * Return `true` if this variable element did not have an explicit type
+   * specified for it.
+   */
+  bool get hasImplicitType;
+
+  /**
+   * Return a synthetic function representing this variable's initializer, or
+   * `null` if this variable does not have an initializer. The function will
+   * have no parameters. The return type of the function will be the
+   * compile-time type of the initialization expression.
+   */
+  FunctionElement get initializer;
+
+  /**
+   * Return `true` if this variable was declared with the 'const' modifier.
+   */
+  bool get isConst;
+
+  /**
+   * Return `true` if this variable was declared with the 'final' modifier.
+   * Variables that are declared with the 'const' modifier will return `false`
+   * even though they are implicitly final.
+   */
+  bool get isFinal;
+
+  /**
+   * Return `true` if this variable is potentially mutated somewhere in a
+   * closure. This information is only available for local variables (including
+   * parameters) and only after the compilation unit containing the variable has
+   * been resolved.
+   */
+  bool get isPotentiallyMutatedInClosure;
+
+  /**
+   * Return `true` if this variable is potentially mutated somewhere in its
+   * scope. This information is only available for local variables (including
+   * parameters) and only after the compilation unit containing the variable has
+   * been resolved.
+   */
+  bool get isPotentiallyMutatedInScope;
+
+  /**
+   * Return `true` if this element is a static variable, as per section 8 of the
+   * Dart Language Specification:
+   *
+   * > A static variable is a variable that is not associated with a particular
+   * > instance, but rather with an entire library or class. Static variables
+   * > include library variables and class variables. Class variables are
+   * > variables whose declaration is immediately nested inside a class
+   * > declaration and includes the modifier static. A library variable is
+   * > implicitly static.
+   */
+  bool get isStatic;
+
+  /**
+   * Return the declared type of this variable, or `null` if the variable did
+   * not have a declared type (such as if it was declared using the keyword
+   * 'var').
+   */
+  DartType get type;
+}