Removed fixed dependencies

packages/analyzer/lib/src/dart/element/builder.dart

Index: packages/analyzer/lib/src/dart/element/builder.dart
diff --git a/packages/analyzer/lib/src/dart/element/builder.dart b/packages/analyzer/lib/src/dart/element/builder.dart
new file mode 100644
index 0000000000000000000000000000000000000000..7e06a56497098689ed756cbcebe52ee6e1bc0606
--- /dev/null
+++ b/packages/analyzer/lib/src/dart/element/builder.dart
@@ -0,0 +1,1465 @@
+// 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.src.dart.element.builder;
+
+import 'dart:collection';
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/token.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/dart/element/type.dart';
+import 'package:analyzer/error/error.dart';
+import 'package:analyzer/exception/exception.dart';
+import 'package:analyzer/src/dart/element/element.dart';
+import 'package:analyzer/src/dart/element/type.dart';
+import 'package:analyzer/src/error/codes.dart';
+import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/resolver.dart';
+import 'package:analyzer/src/generated/sdk.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/generated/utilities_dart.dart';
+
+/**
+ * A `CompilationUnitBuilder` builds an element model for a single compilation
+ * unit.
+ */
+class CompilationUnitBuilder {
+  /**
+   * Build the compilation unit element for the given [source] based on the
+   * compilation [unit] associated with the source. Throw an AnalysisException
+   * if the element could not be built.  [librarySource] is the source for the
+   * containing library.
+   */
+  CompilationUnitElementImpl buildCompilationUnit(
+      Source source, CompilationUnit unit, Source librarySource) {
+    return PerformanceStatistics.resolve.makeCurrentWhile(() {
+      if (unit == null) {
+        return null;
+      }
+      ElementHolder holder = new ElementHolder();
+      CompilationUnitElementImpl element =
+          new CompilationUnitElementImpl(source.shortName);
+      ElementBuilder builder = new ElementBuilder(holder, element);
+      unit.accept(builder);
+      element.accessors = holder.accessors;
+      element.enums = holder.enums;
+      element.functions = holder.functions;
+      element.source = source;
+      element.librarySource = librarySource;
+      element.typeAliases = holder.typeAliases;
+      element.types = holder.types;
+      element.topLevelVariables = holder.topLevelVariables;
+      unit.element = element;
+      holder.validate();
+      return element;
+    });
+  }
+}
+
+/**
+ * Instances of the class `DirectiveElementBuilder` build elements for top
+ * level library directives.
+ */
+class DirectiveElementBuilder extends SimpleAstVisitor<Object> {
+  /**
+   * The analysis context within which directive elements are being built.
+   */
+  final AnalysisContext context;
+
+  /**
+   * The library element for which directive elements are being built.
+   */
+  final LibraryElementImpl libraryElement;
+
+  /**
+   * Map from sources referenced by this library to their modification times.
+   */
+  final Map<Source, int> sourceModificationTimeMap;
+
+  /**
+   * Map from sources imported by this library to their corresponding library
+   * elements.
+   */
+  final Map<Source, LibraryElement> importLibraryMap;
+
+  /**
+   * Map from sources imported by this library to their corresponding source
+   * kinds.
+   */
+  final Map<Source, SourceKind> importSourceKindMap;
+
+  /**
+   * Map from sources exported by this library to their corresponding library
+   * elements.
+   */
+  final Map<Source, LibraryElement> exportLibraryMap;
+
+  /**
+   * Map from sources exported by this library to their corresponding source
+   * kinds.
+   */
+  final Map<Source, SourceKind> exportSourceKindMap;
+
+  /**
+   * The [ImportElement]s created so far.
+   */
+  final List<ImportElement> imports = <ImportElement>[];
+
+  /**
+   * The [ExportElement]s created so far.
+   */
+  final List<ExportElement> exports = <ExportElement>[];
+
+  /**
+   * The errors found while building directive elements.
+   */
+  final List<AnalysisError> errors = <AnalysisError>[];
+
+  /**
+   * Map from prefix names to their corresponding elements.
+   */
+  final HashMap<String, PrefixElementImpl> nameToPrefixMap =
+      new HashMap<String, PrefixElementImpl>();
+
+  /**
+   * Indicates whether an explicit import of `dart:core` has been found.
+   */
+  bool explicitlyImportsCore = false;
+
+  DirectiveElementBuilder(
+      this.context,
+      this.libraryElement,
+      this.sourceModificationTimeMap,
+      this.importLibraryMap,
+      this.importSourceKindMap,
+      this.exportLibraryMap,
+      this.exportSourceKindMap);
+
+  @override
+  Object visitCompilationUnit(CompilationUnit node) {
+    //
+    // Resolve directives.
+    //
+    for (Directive directive in node.directives) {
+      directive.accept(this);
+    }
+    //
+    // Ensure "dart:core" import.
+    //
+    Source librarySource = libraryElement.source;
+    Source coreLibrarySource = context.sourceFactory.forUri(DartSdk.DART_CORE);
+    if (!explicitlyImportsCore && coreLibrarySource != librarySource) {
+      ImportElementImpl importElement = new ImportElementImpl(-1);
+      importElement.importedLibrary = importLibraryMap[coreLibrarySource];
+      importElement.synthetic = true;
+      imports.add(importElement);
+    }
+    //
+    // Populate the library element.
+    //
+    libraryElement.imports = imports;
+    libraryElement.exports = exports;
+    return null;
+  }
+
+  @override
+  Object visitExportDirective(ExportDirective node) {
+    // Remove previous element. (It will remain null if the target is missing.)
+    node.element = null;
+    Source exportedSource = node.selectedSource;
+    int exportedTime = sourceModificationTimeMap[exportedSource] ?? -1;
+    // The exported source will be null if the URI in the export
+    // directive was invalid.
+    LibraryElement exportedLibrary = exportLibraryMap[exportedSource];
+    if (exportedLibrary != null) {
+      ExportElementImpl exportElement = new ExportElementImpl(node.offset);
+      exportElement.metadata = _getElementAnnotations(node.metadata);
+      StringLiteral uriLiteral = node.uri;
+      if (uriLiteral != null) {
+        exportElement.uriOffset = uriLiteral.offset;
+        exportElement.uriEnd = uriLiteral.end;
+      }
+      exportElement.uri = node.selectedUriContent;
+      exportElement.combinators = _buildCombinators(node);
+      exportElement.exportedLibrary = exportedLibrary;
+      setElementDocumentationComment(exportElement, node);
+      node.element = exportElement;
+      exports.add(exportElement);
+      if (exportedTime >= 0 &&
+          exportSourceKindMap[exportedSource] != SourceKind.LIBRARY) {
+        int offset = node.offset;
+        int length = node.length;
+        if (uriLiteral != null) {
+          offset = uriLiteral.offset;
+          length = uriLiteral.length;
+        }
+        errors.add(new AnalysisError(
+            libraryElement.source,
+            offset,
+            length,
+            CompileTimeErrorCode.EXPORT_OF_NON_LIBRARY,
+            [uriLiteral.toSource()]));
+      }
+    }
+    return null;
+  }
+
+  @override
+  Object visitImportDirective(ImportDirective node) {
+    // Remove previous element. (It will remain null if the target is missing.)
+    node.element = null;
+    Source importedSource = node.selectedSource;
+    int importedTime = sourceModificationTimeMap[importedSource] ?? -1;
+    // The imported source will be null if the URI in the import
+    // directive was invalid.
+    LibraryElement importedLibrary = importLibraryMap[importedSource];
+    if (importedLibrary != null) {
+      if (importedLibrary.isDartCore) {
+        explicitlyImportsCore = true;
+      }
+      ImportElementImpl importElement = new ImportElementImpl(node.offset);
+      importElement.metadata = _getElementAnnotations(node.metadata);
+      StringLiteral uriLiteral = node.uri;
+      if (uriLiteral != null) {
+        importElement.uriOffset = uriLiteral.offset;
+        importElement.uriEnd = uriLiteral.end;
+      }
+      importElement.uri = node.selectedUriContent;
+      importElement.deferred = node.deferredKeyword != null;
+      importElement.combinators = _buildCombinators(node);
+      importElement.importedLibrary = importedLibrary;
+      setElementDocumentationComment(importElement, node);
+      SimpleIdentifier prefixNode = node.prefix;
+      if (prefixNode != null) {
+        importElement.prefixOffset = prefixNode.offset;
+        String prefixName = prefixNode.name;
+        PrefixElementImpl prefix = nameToPrefixMap[prefixName];
+        if (prefix == null) {
+          prefix = new PrefixElementImpl.forNode(prefixNode);
+          nameToPrefixMap[prefixName] = prefix;
+        }
+        importElement.prefix = prefix;
+        prefixNode.staticElement = prefix;
+      }
+      node.element = importElement;
+      imports.add(importElement);
+      if (importedTime >= 0 &&
+          importSourceKindMap[importedSource] != SourceKind.LIBRARY) {
+        int offset = node.offset;
+        int length = node.length;
+        if (uriLiteral != null) {
+          offset = uriLiteral.offset;
+          length = uriLiteral.length;
+        }
+        ErrorCode errorCode = importElement.isDeferred
+            ? StaticWarningCode.IMPORT_OF_NON_LIBRARY
+            : CompileTimeErrorCode.IMPORT_OF_NON_LIBRARY;
+        errors.add(new AnalysisError(libraryElement.source, offset, length,
+            errorCode, [uriLiteral.toSource()]));
+      }
+    }
+    return null;
+  }
+
+  @override
+  Object visitLibraryDirective(LibraryDirective node) {
+    (node.element as LibraryElementImpl)?.metadata =
+        _getElementAnnotations(node.metadata);
+    return null;
+  }
+
+  @override
+  Object visitPartDirective(PartDirective node) {
+    (node.element as CompilationUnitElementImpl)?.metadata =
+        _getElementAnnotations(node.metadata);
+    return null;
+  }
+
+  /**
+   * Gather a list of the [ElementAnnotation]s referred to by the [Annotation]s
+   * in [metadata].
+   */
+  List<ElementAnnotation> _getElementAnnotations(
+      NodeList<Annotation> metadata) {
+    if (metadata.isEmpty) {
+      return ElementAnnotation.EMPTY_LIST;
+    }
+    return metadata.map((Annotation a) => a.elementAnnotation).toList();
+  }
+
+  /**
+   * Build the element model representing the combinators declared by
+   * the given [directive].
+   */
+  static List<NamespaceCombinator> _buildCombinators(
+      NamespaceDirective directive) {
+    _NamespaceCombinatorBuilder namespaceCombinatorBuilder =
+        new _NamespaceCombinatorBuilder();
+    for (Combinator combinator in directive.combinators) {
+      combinator.accept(namespaceCombinatorBuilder);
+    }
+    return namespaceCombinatorBuilder.combinators;
+  }
+}
+
+/**
+ * Instances of the class `ElementBuilder` traverse an AST structure and build the element
+ * model representing the AST structure.
+ */
+class ElementBuilder extends RecursiveAstVisitor<Object> {
+  /**
+   * The compilation unit element into which the elements being built will be
+   * stored.
+   */
+  final CompilationUnitElementImpl compilationUnitElement;
+
+  /**
+   * The element holder associated with the element that is currently being built.
+   */
+  ElementHolder _currentHolder;
+
+  /**
+   * A flag indicating whether a variable declaration is within the body of a method or function.
+   */
+  bool _inFunction = false;
+
+  /**
+   * A collection holding the elements defined in a class that need to have
+   * their function type fixed to take into account type parameters of the
+   * enclosing class, or `null` if we are not currently processing nodes within
+   * a class.
+   */
+  List<ExecutableElementImpl> _functionTypesToFix = null;
+
+  /**
+   * A table mapping field names to field elements for the fields defined in the current class, or
+   * `null` if we are not in the scope of a class.
+   */
+  HashMap<String, FieldElement> _fieldMap;
+
+  /**
+   * Initialize a newly created element builder to build the elements for a
+   * compilation unit. The [initialHolder] is the element holder to which the
+   * children of the visited compilation unit node will be added.
+   */
+  ElementBuilder(ElementHolder initialHolder, this.compilationUnitElement) {
+    _currentHolder = initialHolder;
+  }
+
+  /**
+   * Prepares for incremental resolution of a function body.
+   */
+  void initForFunctionBodyIncrementalResolution() {
+    _inFunction = true;
+  }
+
+  @override
+  Object visitAnnotation(Annotation node) {
+    // Although it isn't valid to do so because closures are not constant
+    // expressions, it's possible for one of the arguments to the constructor to
+    // contain a closure. Wrapping the processing of the annotation this way
+    // prevents these closures from being added to the list of functions in the
+    // annotated declaration.
+    ElementHolder holder = new ElementHolder();
+    ElementHolder previousHolder = _currentHolder;
+    _currentHolder = holder;
+    try {
+      super.visitAnnotation(node);
+    } finally {
+      _currentHolder = previousHolder;
+    }
+    return null;
+  }
+
+  @override
+  Object visitCatchClause(CatchClause node) {
+    SimpleIdentifier exceptionParameter = node.exceptionParameter;
+    if (exceptionParameter != null) {
+      // exception
+      LocalVariableElementImpl exception =
+          new LocalVariableElementImpl.forNode(exceptionParameter);
+      if (node.exceptionType == null) {
+        exception.hasImplicitType = true;
+      }
+      exception.setVisibleRange(node.offset, node.length);
+      _currentHolder.addLocalVariable(exception);
+      exceptionParameter.staticElement = exception;
+      // stack trace
+      SimpleIdentifier stackTraceParameter = node.stackTraceParameter;
+      if (stackTraceParameter != null) {
+        LocalVariableElementImpl stackTrace =
+            new LocalVariableElementImpl.forNode(stackTraceParameter);
+        _setCodeRange(stackTrace, stackTraceParameter);
+        stackTrace.setVisibleRange(node.offset, node.length);
+        _currentHolder.addLocalVariable(stackTrace);
+        stackTraceParameter.staticElement = stackTrace;
+      }
+    }
+    return super.visitCatchClause(node);
+  }
+
+  @override
+  Object visitClassDeclaration(ClassDeclaration node) {
+    ElementHolder holder = new ElementHolder();
+    _functionTypesToFix = new List<ExecutableElementImpl>();
+    //
+    // Process field declarations before constructors and methods so that field
+    // formal parameters can be correctly resolved to their fields.
+    //
+    ElementHolder previousHolder = _currentHolder;
+    _currentHolder = holder;
+    try {
+      List<ClassMember> nonFields = new List<ClassMember>();
+      node.visitChildren(
+          new _ElementBuilder_visitClassDeclaration(this, nonFields));
+      _buildFieldMap(holder.fieldsWithoutFlushing);
+      int count = nonFields.length;
+      for (int i = 0; i < count; i++) {
+        nonFields[i].accept(this);
+      }
+    } finally {
+      _currentHolder = previousHolder;
+    }
+    SimpleIdentifier className = node.name;
+    ClassElementImpl element = new ClassElementImpl.forNode(className);
+    _setCodeRange(element, node);
+    element.metadata = _createElementAnnotations(node.metadata);
+    element.typeParameters = holder.typeParameters;
+    setElementDocumentationComment(element, node);
+    element.abstract = node.isAbstract;
+    element.accessors = holder.accessors;
+    List<ConstructorElement> constructors = holder.constructors;
+    if (constructors.isEmpty) {
+      constructors = _createDefaultConstructors(element);
+    }
+    element.constructors = constructors;
+    element.fields = holder.fields;
+    element.methods = holder.methods;
+    // Function types must be initialized after the enclosing element has been
+    // set, for them to pick up the type parameters.
+    for (ExecutableElementImpl e in _functionTypesToFix) {
+      e.type = new FunctionTypeImpl(e);
+    }
+    _functionTypesToFix = null;
+    _currentHolder.addType(element);
+    className.staticElement = element;
+    _fieldMap = null;
+    holder.validate();
+    return null;
+  }
+
+  @override
+  Object visitClassTypeAlias(ClassTypeAlias node) {
+    ElementHolder holder = new ElementHolder();
+    _visitChildren(holder, node);
+    SimpleIdentifier className = node.name;
+    ClassElementImpl element = new ClassElementImpl.forNode(className);
+    _setCodeRange(element, node);
+    element.metadata = _createElementAnnotations(node.metadata);
+    element.abstract = node.abstractKeyword != null;
+    element.mixinApplication = true;
+    element.typeParameters = holder.typeParameters;
+    setElementDocumentationComment(element, node);
+    _currentHolder.addType(element);
+    className.staticElement = element;
+    holder.validate();
+    return null;
+  }
+
+  @override
+  Object visitCompilationUnit(CompilationUnit node) {
+    if (compilationUnitElement is ElementImpl) {
+      _setCodeRange(compilationUnitElement, node);
+    }
+    return super.visitCompilationUnit(node);
+  }
+
+  @override
+  Object visitConstructorDeclaration(ConstructorDeclaration node) {
+    ElementHolder holder = new ElementHolder();
+    bool wasInFunction = _inFunction;
+    _inFunction = true;
+    try {
+      _visitChildren(holder, node);
+    } finally {
+      _inFunction = wasInFunction;
+    }
+    FunctionBody body = node.body;
+    SimpleIdentifier constructorName = node.name;
+    ConstructorElementImpl element =
+        new ConstructorElementImpl.forNode(constructorName);
+    _setCodeRange(element, node);
+    element.metadata = _createElementAnnotations(node.metadata);
+    setElementDocumentationComment(element, node);
+    if (node.externalKeyword != null) {
+      element.external = true;
+    }
+    if (node.factoryKeyword != null) {
+      element.factory = true;
+    }
+    element.functions = holder.functions;
+    element.labels = holder.labels;
+    element.localVariables = holder.localVariables;
+    element.parameters = holder.parameters;
+    element.const2 = node.constKeyword != null;
+    if (body.isAsynchronous) {
+      element.asynchronous = true;
+    }
+    if (body.isGenerator) {
+      element.generator = true;
+    }
+    _currentHolder.addConstructor(element);
+    node.element = element;
+    if (constructorName == null) {
+      Identifier returnType = node.returnType;
+      if (returnType != null) {
+        element.nameOffset = returnType.offset;
+        element.nameEnd = returnType.end;
+      }
+    } else {
+      constructorName.staticElement = element;
+      element.periodOffset = node.period.offset;
+      element.nameEnd = constructorName.end;
+    }
+    holder.validate();
+    return null;
+  }
+
+  @override
+  Object visitDeclaredIdentifier(DeclaredIdentifier node) {
+    SimpleIdentifier variableName = node.identifier;
+    LocalVariableElementImpl element =
+        new LocalVariableElementImpl.forNode(variableName);
+    _setCodeRange(element, node);
+    element.metadata = _createElementAnnotations(node.metadata);
+    ForEachStatement statement = node.parent as ForEachStatement;
+    element.setVisibleRange(statement.offset, statement.length);
+    element.const3 = node.isConst;
+    element.final2 = node.isFinal;
+    if (node.type == null) {
+      element.hasImplicitType = true;
+    }
+    _currentHolder.addLocalVariable(element);
+    variableName.staticElement = element;
+    return super.visitDeclaredIdentifier(node);
+  }
+
+  @override
+  Object visitDefaultFormalParameter(DefaultFormalParameter node) {
+    ElementHolder holder = new ElementHolder();
+    NormalFormalParameter normalParameter = node.parameter;
+    SimpleIdentifier parameterName = normalParameter.identifier;
+    ParameterElementImpl parameter;
+    if (normalParameter is FieldFormalParameter) {
+      parameter =
+          new DefaultFieldFormalParameterElementImpl.forNode(parameterName);
+      FieldElement field =
+          _fieldMap == null ? null : _fieldMap[parameterName.name];
+      if (field != null) {
+        (parameter as DefaultFieldFormalParameterElementImpl).field = field;
+      }
+    } else {
+      parameter = new DefaultParameterElementImpl.forNode(parameterName);
+    }
+    _setCodeRange(parameter, node);
+    parameter.const3 = node.isConst;
+    parameter.final2 = node.isFinal;
+    parameter.parameterKind = node.kind;
+    // set initializer, default value range
+    Expression defaultValue = node.defaultValue;
+    if (defaultValue != null) {
+      _visit(holder, defaultValue);
+      FunctionElementImpl initializer =
+          new FunctionElementImpl.forOffset(defaultValue.beginToken.offset);
+      initializer.hasImplicitReturnType = true;
+      initializer.functions = holder.functions;
+      initializer.labels = holder.labels;
+      initializer.localVariables = holder.localVariables;
+      initializer.parameters = holder.parameters;
+      initializer.synthetic = true;
+      initializer.type = new FunctionTypeImpl(initializer);
+      parameter.initializer = initializer;
+      parameter.defaultValueCode = defaultValue.toSource();
+    }
+    // visible range
+    _setParameterVisibleRange(node, parameter);
+    if (normalParameter is SimpleFormalParameter &&
+        normalParameter.type == null) {
+      parameter.hasImplicitType = true;
+    }
+    _currentHolder.addParameter(parameter);
+    parameterName.staticElement = parameter;
+    normalParameter.accept(this);
+    holder.validate();
+    return null;
+  }
+
+  @override
+  Object visitEnumDeclaration(EnumDeclaration node) {
+    SimpleIdentifier enumName = node.name;
+    EnumElementImpl enumElement = new EnumElementImpl.forNode(enumName);
+    _setCodeRange(enumElement, node);
+    enumElement.metadata = _createElementAnnotations(node.metadata);
+    setElementDocumentationComment(enumElement, node);
+    InterfaceTypeImpl enumType = enumElement.type;
+    //
+    // Build the elements for the constants. These are minimal elements; the
+    // rest of the constant elements (and elements for other fields) must be
+    // built later after we can access the type provider.
+    //
+    List<FieldElement> fields = new List<FieldElement>();
+    NodeList<EnumConstantDeclaration> constants = node.constants;
+    for (EnumConstantDeclaration constant in constants) {
+      SimpleIdentifier constantName = constant.name;
+      FieldElementImpl constantField =
+          new ConstFieldElementImpl.forNode(constantName);
+      constantField.static = true;
+      constantField.const3 = true;
+      constantField.type = enumType;
+      setElementDocumentationComment(constantField, constant);
+      fields.add(constantField);
+      new PropertyAccessorElementImpl_ImplicitGetter(constantField);
+      constantName.staticElement = constantField;
+    }
+    enumElement.fields = fields;
+
+    _currentHolder.addEnum(enumElement);
+    enumName.staticElement = enumElement;
+    return super.visitEnumDeclaration(node);
+  }
+
+  @override
+  Object visitExportDirective(ExportDirective node) {
+    List<ElementAnnotation> annotations =
+        _createElementAnnotations(node.metadata);
+    compilationUnitElement.setAnnotations(node.offset, annotations);
+    return super.visitExportDirective(node);
+  }
+
+  @override
+  Object visitFieldFormalParameter(FieldFormalParameter node) {
+    if (node.parent is! DefaultFormalParameter) {
+      SimpleIdentifier parameterName = node.identifier;
+      FieldElement field =
+          _fieldMap == null ? null : _fieldMap[parameterName.name];
+      FieldFormalParameterElementImpl parameter =
+          new FieldFormalParameterElementImpl.forNode(parameterName);
+      _setCodeRange(parameter, node);
+      parameter.const3 = node.isConst;
+      parameter.final2 = node.isFinal;
+      parameter.parameterKind = node.kind;
+      if (field != null) {
+        parameter.field = field;
+      }
+      _currentHolder.addParameter(parameter);
+      parameterName.staticElement = parameter;
+    }
+    //
+    // The children of this parameter include any parameters defined on the type
+    // of this parameter.
+    //
+    ElementHolder holder = new ElementHolder();
+    _visitChildren(holder, node);
+    ParameterElementImpl element = node.element;
+    element.metadata = _createElementAnnotations(node.metadata);
+    element.parameters = holder.parameters;
+    element.typeParameters = holder.typeParameters;
+    holder.validate();
+    return null;
+  }
+
+  @override
+  Object visitFunctionDeclaration(FunctionDeclaration node) {
+    FunctionExpression expression = node.functionExpression;
+    if (expression != null) {
+      ElementHolder holder = new ElementHolder();
+      bool wasInFunction = _inFunction;
+      _inFunction = true;
+      try {
+        _visitChildren(holder, node);
+      } finally {
+        _inFunction = wasInFunction;
+      }
+      FunctionBody body = expression.body;
+      Token property = node.propertyKeyword;
+      if (property == null || _inFunction) {
+        SimpleIdentifier functionName = node.name;
+        FunctionElementImpl element =
+            new FunctionElementImpl.forNode(functionName);
+        _setCodeRange(element, node);
+        element.metadata = _createElementAnnotations(node.metadata);
+        setElementDocumentationComment(element, node);
+        if (node.externalKeyword != null) {
+          element.external = true;
+        }
+        element.functions = holder.functions;
+        element.labels = holder.labels;
+        element.localVariables = holder.localVariables;
+        element.parameters = holder.parameters;
+        element.typeParameters = holder.typeParameters;
+        if (body.isAsynchronous) {
+          element.asynchronous = true;
+        }
+        if (body.isGenerator) {
+          element.generator = true;
+        }
+        if (_inFunction) {
+          Block enclosingBlock = node.getAncestor((node) => node is Block);
+          if (enclosingBlock != null) {
+            element.setVisibleRange(
+                enclosingBlock.offset, enclosingBlock.length);
+          }
+        }
+        if (node.returnType == null) {
+          element.hasImplicitReturnType = true;
+        }
+        _currentHolder.addFunction(element);
+        expression.element = element;
+        functionName.staticElement = element;
+      } else {
+        SimpleIdentifier propertyNameNode = node.name;
+        if (propertyNameNode == null) {
+          // TODO(brianwilkerson) Report this internal error.
+          return null;
+        }
+        String propertyName = propertyNameNode.name;
+        TopLevelVariableElementImpl variable = _currentHolder
+            .getTopLevelVariable(propertyName) as TopLevelVariableElementImpl;
+        if (variable == null) {
+          variable = new TopLevelVariableElementImpl(node.name.name, -1);
+          variable.final2 = true;
+          variable.synthetic = true;
+          _currentHolder.addTopLevelVariable(variable);
+        }
+        if (node.isGetter) {
+          PropertyAccessorElementImpl getter =
+              new PropertyAccessorElementImpl.forNode(propertyNameNode);
+          _setCodeRange(getter, node);
+          getter.metadata = _createElementAnnotations(node.metadata);
+          setElementDocumentationComment(getter, node);
+          if (node.externalKeyword != null) {
+            getter.external = true;
+          }
+          getter.functions = holder.functions;
+          getter.labels = holder.labels;
+          getter.localVariables = holder.localVariables;
+          if (body.isAsynchronous) {
+            getter.asynchronous = true;
+          }
+          if (body.isGenerator) {
+            getter.generator = true;
+          }
+          getter.variable = variable;
+          getter.getter = true;
+          getter.static = true;
+          variable.getter = getter;
+          if (node.returnType == null) {
+            getter.hasImplicitReturnType = true;
+          }
+          _currentHolder.addAccessor(getter);
+          expression.element = getter;
+          propertyNameNode.staticElement = getter;
+        } else {
+          PropertyAccessorElementImpl setter =
+              new PropertyAccessorElementImpl.forNode(propertyNameNode);
+          _setCodeRange(setter, node);
+          setter.metadata = _createElementAnnotations(node.metadata);
+          setElementDocumentationComment(setter, node);
+          if (node.externalKeyword != null) {
+            setter.external = true;
+          }
+          setter.functions = holder.functions;
+          setter.labels = holder.labels;
+          setter.localVariables = holder.localVariables;
+          setter.parameters = holder.parameters;
+          if (body.isAsynchronous) {
+            setter.asynchronous = true;
+          }
+          if (body.isGenerator) {
+            setter.generator = true;
+          }
+          setter.variable = variable;
+          setter.setter = true;
+          setter.static = true;
+          if (node.returnType == null) {
+            setter.hasImplicitReturnType = true;
+          }
+          variable.setter = setter;
+          variable.final2 = false;
+          _currentHolder.addAccessor(setter);
+          expression.element = setter;
+          propertyNameNode.staticElement = setter;
+        }
+      }
+      holder.validate();
+    }
+    return null;
+  }
+
+  @override
+  Object visitFunctionExpression(FunctionExpression node) {
+    if (node.parent is FunctionDeclaration) {
+      // visitFunctionDeclaration has already created the element for the
+      // declaration.  We just need to visit children.
+      return super.visitFunctionExpression(node);
+    }
+    ElementHolder holder = new ElementHolder();
+    bool wasInFunction = _inFunction;
+    _inFunction = true;
+    try {
+      _visitChildren(holder, node);
+    } finally {
+      _inFunction = wasInFunction;
+    }
+    FunctionBody body = node.body;
+    FunctionElementImpl element =
+        new FunctionElementImpl.forOffset(node.beginToken.offset);
+    _setCodeRange(element, node);
+    element.functions = holder.functions;
+    element.labels = holder.labels;
+    element.localVariables = holder.localVariables;
+    element.parameters = holder.parameters;
+    element.typeParameters = holder.typeParameters;
+    if (body.isAsynchronous) {
+      element.asynchronous = true;
+    }
+    if (body.isGenerator) {
+      element.generator = true;
+    }
+    if (_inFunction) {
+      Block enclosingBlock = node.getAncestor((node) => node is Block);
+      if (enclosingBlock != null) {
+        element.setVisibleRange(enclosingBlock.offset, enclosingBlock.length);
+      }
+    }
+    if (_functionTypesToFix != null) {
+      _functionTypesToFix.add(element);
+    } else {
+      element.type = new FunctionTypeImpl(element);
+    }
+    element.hasImplicitReturnType = true;
+    _currentHolder.addFunction(element);
+    node.element = element;
+    holder.validate();
+    return null;
+  }
+
+  @override
+  Object visitFunctionTypeAlias(FunctionTypeAlias node) {
+    ElementHolder holder = new ElementHolder();
+    _visitChildren(holder, node);
+    SimpleIdentifier aliasName = node.name;
+    List<ParameterElement> parameters = holder.parameters;
+    List<TypeParameterElement> typeParameters = holder.typeParameters;
+    FunctionTypeAliasElementImpl element =
+        new FunctionTypeAliasElementImpl.forNode(aliasName);
+    _setCodeRange(element, node);
+    element.metadata = _createElementAnnotations(node.metadata);
+    setElementDocumentationComment(element, node);
+    element.parameters = parameters;
+    element.typeParameters = typeParameters;
+    _createTypeParameterTypes(typeParameters);
+    element.type = new FunctionTypeImpl.forTypedef(element);
+    _currentHolder.addTypeAlias(element);
+    aliasName.staticElement = element;
+    holder.validate();
+    return null;
+  }
+
+  @override
+  Object visitFunctionTypedFormalParameter(FunctionTypedFormalParameter node) {
+    if (node.parent is! DefaultFormalParameter) {
+      SimpleIdentifier parameterName = node.identifier;
+      ParameterElementImpl parameter =
+          new ParameterElementImpl.forNode(parameterName);
+      _setCodeRange(parameter, node);
+      parameter.parameterKind = node.kind;
+      _setParameterVisibleRange(node, parameter);
+      _currentHolder.addParameter(parameter);
+      parameterName.staticElement = parameter;
+    }
+    //
+    // The children of this parameter include any parameters defined on the type
+    //of this parameter.
+    //
+    ElementHolder holder = new ElementHolder();
+    _visitChildren(holder, node);
+    ParameterElementImpl element = node.element;
+    element.metadata = _createElementAnnotations(node.metadata);
+    element.parameters = holder.parameters;
+    element.typeParameters = holder.typeParameters;
+    holder.validate();
+    return null;
+  }
+
+  @override
+  Object visitImportDirective(ImportDirective node) {
+    List<ElementAnnotation> annotations =
+        _createElementAnnotations(node.metadata);
+    compilationUnitElement.setAnnotations(node.offset, annotations);
+    return super.visitImportDirective(node);
+  }
+
+  @override
+  Object visitLabeledStatement(LabeledStatement node) {
+    bool onSwitchStatement = node.statement is SwitchStatement;
+    for (Label label in node.labels) {
+      SimpleIdentifier labelName = label.label;
+      LabelElementImpl element =
+          new LabelElementImpl.forNode(labelName, onSwitchStatement, false);
+      _currentHolder.addLabel(element);
+      labelName.staticElement = element;
+    }
+    return super.visitLabeledStatement(node);
+  }
+
+  @override
+  Object visitLibraryDirective(LibraryDirective node) {
+    List<ElementAnnotation> annotations =
+        _createElementAnnotations(node.metadata);
+    compilationUnitElement.setAnnotations(node.offset, annotations);
+    return super.visitLibraryDirective(node);
+  }
+
+  @override
+  Object visitMethodDeclaration(MethodDeclaration node) {
+    try {
+      ElementHolder holder = new ElementHolder();
+      bool wasInFunction = _inFunction;
+      _inFunction = true;
+      try {
+        _visitChildren(holder, node);
+      } finally {
+        _inFunction = wasInFunction;
+      }
+      bool isStatic = node.isStatic;
+      Token property = node.propertyKeyword;
+      FunctionBody body = node.body;
+      if (property == null) {
+        SimpleIdentifier methodName = node.name;
+        String nameOfMethod = methodName.name;
+        if (nameOfMethod == TokenType.MINUS.lexeme &&
+            node.parameters.parameters.length == 0) {
+          nameOfMethod = "unary-";
+        }
+        MethodElementImpl element =
+            new MethodElementImpl(nameOfMethod, methodName.offset);
+        _setCodeRange(element, node);
+        element.metadata = _createElementAnnotations(node.metadata);
+        setElementDocumentationComment(element, node);
+        element.abstract = node.isAbstract;
+        if (node.externalKeyword != null) {
+          element.external = true;
+        }
+        element.functions = holder.functions;
+        element.labels = holder.labels;
+        element.localVariables = holder.localVariables;
+        element.parameters = holder.parameters;
+        element.static = isStatic;
+        element.typeParameters = holder.typeParameters;
+        if (body.isAsynchronous) {
+          element.asynchronous = true;
+        }
+        if (body.isGenerator) {
+          element.generator = true;
+        }
+        if (node.returnType == null) {
+          element.hasImplicitReturnType = true;
+        }
+        _currentHolder.addMethod(element);
+        methodName.staticElement = element;
+      } else {
+        SimpleIdentifier propertyNameNode = node.name;
+        String propertyName = propertyNameNode.name;
+        FieldElementImpl field = _currentHolder.getField(propertyName,
+            synthetic: true) as FieldElementImpl;
+        if (field == null) {
+          field = new FieldElementImpl(node.name.name, -1);
+          field.final2 = true;
+          field.static = isStatic;
+          field.synthetic = true;
+          _currentHolder.addField(field);
+        }
+        if (node.isGetter) {
+          PropertyAccessorElementImpl getter =
+              new PropertyAccessorElementImpl.forNode(propertyNameNode);
+          _setCodeRange(getter, node);
+          getter.metadata = _createElementAnnotations(node.metadata);
+          setElementDocumentationComment(getter, node);
+          if (node.externalKeyword != null) {
+            getter.external = true;
+          }
+          getter.functions = holder.functions;
+          getter.labels = holder.labels;
+          getter.localVariables = holder.localVariables;
+          if (body.isAsynchronous) {
+            getter.asynchronous = true;
+          }
+          if (body.isGenerator) {
+            getter.generator = true;
+          }
+          getter.variable = field;
+          getter.abstract = node.isAbstract;
+          getter.getter = true;
+          getter.static = isStatic;
+          field.getter = getter;
+          if (node.returnType == null) {
+            getter.hasImplicitReturnType = true;
+          }
+          _currentHolder.addAccessor(getter);
+          propertyNameNode.staticElement = getter;
+        } else {
+          PropertyAccessorElementImpl setter =
+              new PropertyAccessorElementImpl.forNode(propertyNameNode);
+          _setCodeRange(setter, node);
+          setter.metadata = _createElementAnnotations(node.metadata);
+          setElementDocumentationComment(setter, node);
+          if (node.externalKeyword != null) {
+            setter.external = true;
+          }
+          setter.functions = holder.functions;
+          setter.labels = holder.labels;
+          setter.localVariables = holder.localVariables;
+          setter.parameters = holder.parameters;
+          if (body.isAsynchronous) {
+            setter.asynchronous = true;
+          }
+          if (body.isGenerator) {
+            setter.generator = true;
+          }
+          setter.variable = field;
+          setter.abstract = node.isAbstract;
+          setter.setter = true;
+          setter.static = isStatic;
+          if (node.returnType == null) {
+            setter.hasImplicitReturnType = true;
+          }
+          field.setter = setter;
+          field.final2 = false;
+          _currentHolder.addAccessor(setter);
+          propertyNameNode.staticElement = setter;
+        }
+      }
+      holder.validate();
+    } catch (exception, stackTrace) {
+      if (node.name.staticElement == null) {
+        ClassDeclaration classNode =
+            node.getAncestor((node) => node is ClassDeclaration);
+        StringBuffer buffer = new StringBuffer();
+        buffer.write("The element for the method ");
+        buffer.write(node.name);
+        buffer.write(" in ");
+        buffer.write(classNode.name);
+        buffer.write(" was not set while trying to build the element model.");
+        AnalysisEngine.instance.logger.logError(
+            buffer.toString(), new CaughtException(exception, stackTrace));
+      } else {
+        String message =
+            "Exception caught in ElementBuilder.visitMethodDeclaration()";
+        AnalysisEngine.instance.logger
+            .logError(message, new CaughtException(exception, stackTrace));
+      }
+    } finally {
+      if (node.name.staticElement == null) {
+        ClassDeclaration classNode =
+            node.getAncestor((node) => node is ClassDeclaration);
+        StringBuffer buffer = new StringBuffer();
+        buffer.write("The element for the method ");
+        buffer.write(node.name);
+        buffer.write(" in ");
+        buffer.write(classNode.name);
+        buffer.write(" was not set while trying to resolve types.");
+        AnalysisEngine.instance.logger.logError(
+            buffer.toString(),
+            new CaughtException(
+                new AnalysisException(buffer.toString()), null));
+      }
+    }
+    return null;
+  }
+
+  @override
+  Object visitPartDirective(PartDirective node) {
+    List<ElementAnnotation> annotations =
+        _createElementAnnotations(node.metadata);
+    compilationUnitElement.setAnnotations(node.offset, annotations);
+    return super.visitPartDirective(node);
+  }
+
+  @override
+  Object visitSimpleFormalParameter(SimpleFormalParameter node) {
+    if (node.parent is! DefaultFormalParameter) {
+      SimpleIdentifier parameterName = node.identifier;
+      ParameterElementImpl parameter =
+          new ParameterElementImpl.forNode(parameterName);
+      _setCodeRange(parameter, node);
+      parameter.const3 = node.isConst;
+      parameter.final2 = node.isFinal;
+      parameter.parameterKind = node.kind;
+      _setParameterVisibleRange(node, parameter);
+      if (node.type == null) {
+        parameter.hasImplicitType = true;
+      }
+      _currentHolder.addParameter(parameter);
+      parameterName.staticElement = parameter;
+    }
+    super.visitSimpleFormalParameter(node);
+    (node.element as ElementImpl).metadata =
+        _createElementAnnotations(node.metadata);
+    return null;
+  }
+
+  @override
+  Object visitSwitchCase(SwitchCase node) {
+    for (Label label in node.labels) {
+      SimpleIdentifier labelName = label.label;
+      LabelElementImpl element =
+          new LabelElementImpl.forNode(labelName, false, true);
+      _currentHolder.addLabel(element);
+      labelName.staticElement = element;
+    }
+    return super.visitSwitchCase(node);
+  }
+
+  @override
+  Object visitSwitchDefault(SwitchDefault node) {
+    for (Label label in node.labels) {
+      SimpleIdentifier labelName = label.label;
+      LabelElementImpl element =
+          new LabelElementImpl.forNode(labelName, false, true);
+      _currentHolder.addLabel(element);
+      labelName.staticElement = element;
+    }
+    return super.visitSwitchDefault(node);
+  }
+
+  @override
+  Object visitTypeParameter(TypeParameter node) {
+    SimpleIdentifier parameterName = node.name;
+    TypeParameterElementImpl typeParameter =
+        new TypeParameterElementImpl.forNode(parameterName);
+    _setCodeRange(typeParameter, node);
+    typeParameter.metadata = _createElementAnnotations(node.metadata);
+    TypeParameterTypeImpl typeParameterType =
+        new TypeParameterTypeImpl(typeParameter);
+    typeParameter.type = typeParameterType;
+    _currentHolder.addTypeParameter(typeParameter);
+    parameterName.staticElement = typeParameter;
+    return super.visitTypeParameter(node);
+  }
+
+  @override
+  Object visitVariableDeclaration(VariableDeclaration node) {
+    bool isConst = node.isConst;
+    bool isFinal = node.isFinal;
+    bool hasInitializer = node.initializer != null;
+    VariableDeclarationList varList = node.parent;
+    FieldDeclaration fieldNode =
+        varList.parent is FieldDeclaration ? varList.parent : null;
+    VariableElementImpl element;
+    if (fieldNode != null) {
+      SimpleIdentifier fieldName = node.name;
+      FieldElementImpl field;
+      if ((isConst || isFinal && !fieldNode.isStatic) && hasInitializer) {
+        field = new ConstFieldElementImpl.forNode(fieldName);
+      } else {
+        field = new FieldElementImpl.forNode(fieldName);
+      }
+      element = field;
+      field.static = fieldNode.isStatic;
+      _setCodeRange(element, node);
+      setElementDocumentationComment(element, fieldNode);
+      field.hasImplicitType = varList.type == null;
+      _currentHolder.addField(field);
+      fieldName.staticElement = field;
+    } else if (_inFunction) {
+      SimpleIdentifier variableName = node.name;
+      LocalVariableElementImpl variable;
+      if (isConst && hasInitializer) {
+        variable = new ConstLocalVariableElementImpl.forNode(variableName);
+      } else {
+        variable = new LocalVariableElementImpl.forNode(variableName);
+      }
+      element = variable;
+      _setCodeRange(element, node);
+      _setVariableVisibleRange(variable, node);
+      variable.hasImplicitType = varList.type == null;
+      _currentHolder.addLocalVariable(variable);
+      variableName.staticElement = element;
+    } else {
+      SimpleIdentifier variableName = node.name;
+      TopLevelVariableElementImpl variable;
+      if (isConst && hasInitializer) {
+        variable = new ConstTopLevelVariableElementImpl.forNode(variableName);
+      } else {
+        variable = new TopLevelVariableElementImpl.forNode(variableName);
+      }
+      element = variable;
+      _setCodeRange(element, node);
+      if (varList.parent is TopLevelVariableDeclaration) {
+        setElementDocumentationComment(element, varList.parent);
+      }
+      variable.hasImplicitType = varList.type == null;
+      _currentHolder.addTopLevelVariable(variable);
+      variableName.staticElement = element;
+    }
+    element.const3 = isConst;
+    element.final2 = isFinal;
+    if (hasInitializer) {
+      ElementHolder holder = new ElementHolder();
+      _visit(holder, node.initializer);
+      FunctionElementImpl initializer =
+          new FunctionElementImpl.forOffset(node.initializer.beginToken.offset);
+      initializer.hasImplicitReturnType = true;
+      initializer.functions = holder.functions;
+      initializer.labels = holder.labels;
+      initializer.localVariables = holder.localVariables;
+      initializer.synthetic = true;
+      initializer.type = new FunctionTypeImpl(initializer);
+      element.initializer = initializer;
+      holder.validate();
+    }
+    if (element is PropertyInducingElementImpl) {
+      PropertyAccessorElementImpl_ImplicitGetter getter =
+          new PropertyAccessorElementImpl_ImplicitGetter(element);
+      _currentHolder.addAccessor(getter);
+      if (!isConst && !isFinal) {
+        PropertyAccessorElementImpl_ImplicitSetter setter =
+            new PropertyAccessorElementImpl_ImplicitSetter(element);
+        _currentHolder.addAccessor(setter);
+      }
+    }
+    return null;
+  }
+
+  @override
+  Object visitVariableDeclarationList(VariableDeclarationList node) {
+    super.visitVariableDeclarationList(node);
+    AstNode parent = node.parent;
+    List<ElementAnnotation> elementAnnotations;
+    if (parent is FieldDeclaration) {
+      elementAnnotations = _createElementAnnotations(parent.metadata);
+    } else if (parent is TopLevelVariableDeclaration) {
+      elementAnnotations = _createElementAnnotations(parent.metadata);
+    } else {
+      // Local variable declaration
+      elementAnnotations = _createElementAnnotations(node.metadata);
+    }
+    for (VariableDeclaration variableDeclaration in node.variables) {
+      ElementImpl element = variableDeclaration.element as ElementImpl;
+      _setCodeRange(element, node.parent);
+      element.metadata = elementAnnotations;
+    }
+    return null;
+  }
+
+  /**
+   * Build the table mapping field names to field elements for the fields defined in the current
+   * class.
+   *
+   * @param fields the field elements defined in the current class
+   */
+  void _buildFieldMap(List<FieldElement> fields) {
+    _fieldMap = new HashMap<String, FieldElement>();
+    int count = fields.length;
+    for (int i = 0; i < count; i++) {
+      FieldElement field = fields[i];
+      _fieldMap[field.name] ??= field;
+    }
+  }
+
+  /**
+   * Creates the [ConstructorElement]s array with the single default constructor element.
+   *
+   * @param interfaceType the interface type for which to create a default constructor
+   * @return the [ConstructorElement]s array with the single default constructor element
+   */
+  List<ConstructorElement> _createDefaultConstructors(
+      ClassElementImpl definingClass) {
+    ConstructorElementImpl constructor =
+        new ConstructorElementImpl.forNode(null);
+    constructor.synthetic = true;
+    constructor.enclosingElement = definingClass;
+    return <ConstructorElement>[constructor];
+  }
+
+  /**
+   * For each [Annotation] found in [annotations], create a new
+   * [ElementAnnotation] object and set the [Annotation] to point to it.
+   */
+  List<ElementAnnotation> _createElementAnnotations(
+      NodeList<Annotation> annotations) {
+    if (annotations.isEmpty) {
+      return ElementAnnotation.EMPTY_LIST;
+    }
+    return annotations.map((Annotation a) {
+      ElementAnnotationImpl elementAnnotation =
+          new ElementAnnotationImpl(compilationUnitElement);
+      a.elementAnnotation = elementAnnotation;
+      return elementAnnotation;
+    }).toList();
+  }
+
+  /**
+   * Create the types associated with the given type parameters, setting the type of each type
+   * parameter, and return an array of types corresponding to the given parameters.
+   *
+   * @param typeParameters the type parameters for which types are to be created
+   * @return an array of types corresponding to the given parameters
+   */
+  List<DartType> _createTypeParameterTypes(
+      List<TypeParameterElement> typeParameters) {
+    int typeParameterCount = typeParameters.length;
+    List<DartType> typeArguments = new List<DartType>(typeParameterCount);
+    for (int i = 0; i < typeParameterCount; i++) {
+      TypeParameterElementImpl typeParameter =
+          typeParameters[i] as TypeParameterElementImpl;
+      TypeParameterTypeImpl typeParameterType =
+          new TypeParameterTypeImpl(typeParameter);
+      typeParameter.type = typeParameterType;
+      typeArguments[i] = typeParameterType;
+    }
+    return typeArguments;
+  }
+
+  /**
+   * Return the body of the function that contains the given [parameter], or
+   * `null` if no function body could be found.
+   */
+  FunctionBody _getFunctionBody(FormalParameter parameter) {
+    AstNode parent = parameter?.parent?.parent;
+    if (parent is ConstructorDeclaration) {
+      return parent.body;
+    } else if (parent is FunctionExpression) {
+      return parent.body;
+    } else if (parent is MethodDeclaration) {
+      return parent.body;
+    }
+    return null;
+  }
+
+  void _setCodeRange(ElementImpl element, AstNode node) {
+    element.setCodeRange(node.offset, node.length);
+  }
+
+  /**
+   * Sets the visible source range for formal parameter.
+   */
+  void _setParameterVisibleRange(
+      FormalParameter node, ParameterElementImpl element) {
+    FunctionBody body = _getFunctionBody(node);
+    if (body is BlockFunctionBody || body is ExpressionFunctionBody) {
+      element.setVisibleRange(body.offset, body.length);
+    }
+  }
+
+  void _setVariableVisibleRange(
+      LocalVariableElementImpl element, VariableDeclaration node) {
+    AstNode scopeNode;
+    AstNode parent2 = node.parent.parent;
+    if (parent2 is ForStatement) {
+      scopeNode = parent2;
+    } else {
+      scopeNode = node.getAncestor((node) => node is Block);
+    }
+    element.setVisibleRange(scopeNode.offset, scopeNode.length);
+  }
+
+  /**
+   * Make the given holder be the current holder while visiting the given node.
+   *
+   * @param holder the holder that will gather elements that are built while visiting the children
+   * @param node the node to be visited
+   */
+  void _visit(ElementHolder holder, AstNode node) {
+    if (node != null) {
+      ElementHolder previousHolder = _currentHolder;
+      _currentHolder = holder;
+      try {
+        node.accept(this);
+      } finally {
+        _currentHolder = previousHolder;
+      }
+    }
+  }
+
+  /**
+   * Make the given holder be the current holder while visiting the children of the given node.
+   *
+   * @param holder the holder that will gather elements that are built while visiting the children
+   * @param node the node whose children are to be visited
+   */
+  void _visitChildren(ElementHolder holder, AstNode node) {
+    if (node != null) {
+      ElementHolder previousHolder = _currentHolder;
+      _currentHolder = holder;
+      try {
+        node.visitChildren(this);
+      } finally {
+        _currentHolder = previousHolder;
+      }
+    }
+  }
+}
+
+class _ElementBuilder_visitClassDeclaration extends UnifyingAstVisitor<Object> {
+  final ElementBuilder builder;
+
+  List<ClassMember> nonFields;
+
+  _ElementBuilder_visitClassDeclaration(this.builder, this.nonFields) : super();
+
+  @override
+  Object visitConstructorDeclaration(ConstructorDeclaration node) {
+    nonFields.add(node);
+    return null;
+  }
+
+  @override
+  Object visitMethodDeclaration(MethodDeclaration node) {
+    nonFields.add(node);
+    return null;
+  }
+
+  @override
+  Object visitNode(AstNode node) => node.accept(builder);
+}
+
+/**
+ * Instances of the class [_NamespaceCombinatorBuilder] can be used to visit
+ * [Combinator] AST nodes and generate [NamespaceCombinator] elements.
+ */
+class _NamespaceCombinatorBuilder extends SimpleAstVisitor<Object> {
+  /**
+   * Elements generated so far.
+   */
+  final List<NamespaceCombinator> combinators = <NamespaceCombinator>[];
+
+  @override
+  Object visitHideCombinator(HideCombinator node) {
+    HideElementCombinatorImpl hide = new HideElementCombinatorImpl();
+    hide.hiddenNames = _getIdentifiers(node.hiddenNames);
+    combinators.add(hide);
+    return null;
+  }
+
+  @override
+  Object visitShowCombinator(ShowCombinator node) {
+    ShowElementCombinatorImpl show = new ShowElementCombinatorImpl();
+    show.offset = node.offset;
+    show.end = node.end;
+    show.shownNames = _getIdentifiers(node.shownNames);
+    combinators.add(show);
+    return null;
+  }
+
+  /**
+   * Return the lexical identifiers associated with the given [identifiers].
+   */
+  static List<String> _getIdentifiers(NodeList<SimpleIdentifier> identifiers) {
+    return identifiers.map((identifier) => identifier.name).toList();
+  }
+}