Strip more unused features.

lib/facade_converter.ts

+import * as ts from 'typescript';
+
 import * as base from './base';
-import * as ts from 'typescript';
+import {Set} from './base';
+import {DART_LIBRARIES_FOR_BROWSER_TYPES, TS_TO_DART_TYPENAMES} from './dart_libraries_for_browser_types';
 import {Transpiler} from './main';
+import {MergedType} from './merge';
 
 type CallHandler = (c: ts.CallExpression, context: ts.Expression) => void;
 type PropertyHandler = (c: ts.PropertyAccessExpression) => void;
-type Set = {
-  [s: string]: boolean
-};
 
 const FACADE_DEBUG = false;
-
 const FACADE_NODE_MODULES_PREFIX = /^(\.\.\/)*node_modules\//;
 
-function merge(...args: {[key: string]: any}[]): {[key: string]: any} {
-  let returnObject: {[key: string]: any} = {};
-  for (let arg of args) {
-    for (let key of Object.getOwnPropertyNames(arg)) {
-      returnObject[key] = arg[key];
+// These constants must be kept in sync with package:func/func.dart which
+// provides a cannonical set of typedefs defining commonly used function types
+// to simplify specifying function types in Dart.
+const MAX_DART_FUNC_ACTION_PARAMETERS = 4;
+const MAX_DART_FUNC_ACTION_PARAMETERS_OPTIONAL = 1;
+
+/**
+ * Prefix to add to a variable name that leaves the JS name referenced
+ * unchanged.
+ */
+const DART_RESERVED_NAME_PREFIX = 'JS$';
+
+export function fixupIdentifierName(text: string): string {
+  return (FacadeConverter.DART_RESERVED_WORDS.indexOf(text) !== -1 ||
+          FacadeConverter.DART_OTHER_KEYWORDS.indexOf(text) !== -1 || text[0] === '_') ?
+      DART_RESERVED_NAME_PREFIX + text :
+      text;
+}
+
+function numOptionalParameters(parameters: ts.NodeArray<ts.ParameterDeclaration>): number {
+  for (let i = 0; i < parameters.length; ++i) {
+    if (parameters[i].questionToken) return parameters.length - i;
+  }
+  return 0;
+}
+
+function hasVarArgs(parameters: ts.NodeArray<ts.ParameterDeclaration>): boolean {
+  for (let i = 0; i < parameters.length; ++i) {
+    if (parameters[i].dotDotDotToken) return true;
+  }
+  return false;
+}
+
+/**
+ * Generates the JavaScript expression required to reference the node
+ * from the global context. InterfaceDeclarations do not technically correspond
+ * to actual JavaScript objects but we still generate a reference path for them
+ * so that we have a guaranteed unique name.
+ *
+ * Example JS path:
+ * module m1 {
+ *   module m2 {
+ *     class foo { }
+ *   }
+ * }
+ * Path: m1.m2.foo
+ */
+function fullJsPath(node: base.NamedDeclaration): string {
+  let parts: Array<string> = [base.ident(node.name)];
+  let p: ts.Node = node.parent;
+  while (p != null) {
+    let kind = p.kind;
+    if (kind === ts.SyntaxKind.ModuleDeclaration || kind === ts.SyntaxKind.InterfaceDeclaration ||
+        kind === ts.SyntaxKind.ClassDeclaration) {
+      parts.unshift(base.ident((<base.NamedDeclaration>p).name));
+    }
+    p = p.parent;
+  }
+  return parts.join('.');
+}
+
+class DartNameRecord {
+  name: string;
+  constructor(private node: ts.Node, name: string, private library: DartLibrary) {
+    this.name = name;
+  }
+}
+
+export class DartLibrary {
+  constructor(private fileName: string) { this.usedNames = {}; }
+
+  /**
+   * @returns {boolean} whether the name was added.
+   */
+  addName(name: string): boolean {
+    if (Object.prototype.hasOwnProperty.call(this.usedNames, name)) {
+      return false;
+    }
+    this.usedNames[name] = true;
+    return true;
+  }
+
+  private usedNames: Set;
+}
+
+export class NameRewriter {
+  private dartTypes: ts.Map<DartNameRecord> = {};
+  // TODO(jacobr): use libraries to track what library imports need to be
+  // emitted. Complex cases such as ts.SyntaxKind.TypeReference
+  // where emitting the type could require emitting imports to libraries not
+  // specified in the imports listed in TypeScript. Additionally, d.ts files
+  // can contain multiple modules and for readability we may want an option
+  // to emit each of those modules as a separate Dart library. That would also
+  // require tracking what external libraries are referenced.
+  private libraries: ts.Map<DartLibrary> = {};
+
+  private computeName(node: base.NamedDeclaration): DartNameRecord {
+    let fullPath = fullJsPath(node);
+    if (Object.prototype.hasOwnProperty.call(this.dartTypes, fullPath)) {
+      return this.dartTypes[fullPath];
+    }
+    let sourceFile = <ts.SourceFile>base.getAncestor(node, ts.SyntaxKind.SourceFile);
+    let fileName = sourceFile.fileName;
+    let library: DartLibrary;
+    if (Object.prototype.hasOwnProperty.call(this.libraries, fileName)) {
+      library = this.libraries[fileName];
+    } else {
+      library = new DartLibrary(fileName);
+      this.libraries[fileName] = library;
+    }
+    let parts = fullPath.split('.');
+    for (let i = parts.length - 1; i >= 0; i--) {
+      // Find a unique name by including more of the module hierarchy in the
+      // name. This is an arbitrary but hopefully unsurprising scheme to
+      // generate unique names. There may be classes or members with conflicting
+      // names due to a single d.ts file containing multiple modules.
+      // TODO(jacobr): we should suppress this behavior outside of JS Interop
+      // mode and instead generate a compile error if there are conflicting
+      // names.
+      let candidateName = fixupIdentifierName(parts.slice(i).join('_'));
+      if (library.addName(candidateName)) {
+        // Able to add name to library.
+        let ret = new DartNameRecord(node, candidateName, library);
+        this.dartTypes[fullPath] = ret;
+        return ret;
+      }
+    }
+
+    // Usually the module name prefixes should be sufficient to disambiguate
+    // names but sometimes we need to add a numeric prefix as well to
+    // disambiguate. We could alternately append the full module prefix as well
+    // to make the name choice completely unsurprising albeit even uglier.
+    // This case should be very rarely hit.
+    let i = 2;
+    while (true) {
+      let candidateName = parts[parts.length - 1] + i;
+      if (library.addName(candidateName)) {
+        // Able to add name to library.
+        let ret = new DartNameRecord(node, candidateName, library);
+        this.dartTypes[fullPath] = ret;
+        return ret;
+      }
+      i++;
     }
   }
-  return returnObject;
+
+  lookupName(node: base.NamedDeclaration, context: ts.Node) { return this.computeName(node).name; }
 }
 
-
 export class FacadeConverter extends base.TranspilerBase {
   private tc: ts.TypeChecker;
-  private candidateProperties: {[propertyName: string]: boolean} = {};
+  // For the Dart keyword list see
+  // https://www.dartlang.org/docs/dart-up-and-running/ch02.html#keywords
+  static DART_RESERVED_WORDS =
+      ('assert break case catch class const continue default do else enum extends false final ' +
+       'finally for if in is new null rethrow return super switch this throw true try let void ' +
+       'while with')
+          .split(/ /);
+
+  // These are the built-in and limited keywords.
+  static DART_OTHER_KEYWORDS =
+      ('abstract as async await deferred dynamic export external factory get implements import ' +
+       'library operator part set static sync typedef yield call')
+          .split(/ /);
+
   private candidateTypes: {[typeName: string]: boolean} = {};
   private typingsRootRegex: RegExp;
   private genericMethodDeclDepth = 0;
 
-  constructor(transpiler: Transpiler, typingsRoot = '') {
+  constructor(
+      transpiler: Transpiler, typingsRoot = '', private nameRewriter: NameRewriter,
+      private useHtml: boolean) {
     super(transpiler);
-    this.extractPropertyNames(this.callHandlers, this.candidateProperties);
-    this.extractPropertyNames(this.propertyHandlers, this.candidateProperties);
-    this.extractPropertyNames(this.TS_TO_DART_TYPENAMES, this.candidateTypes);
+    if (useHtml) {
+      this.extractPropertyNames(TS_TO_DART_TYPENAMES, this.candidateTypes);
+      Object.keys(DART_LIBRARIES_FOR_BROWSER_TYPES)
+          .forEach((propName) => this.candidateTypes[propName] = true);
+    } else {
+      this.extractPropertyNames(TS_TO_DART_TYPENAMES, this.candidateTypes);
+    }
 
     this.typingsRootRegex = new RegExp('^' + typingsRoot.replace('.', '\\.'));
   }
 
   private extractPropertyNames(m: ts.Map<ts.Map<any>>, candidates: {[k: string]: boolean}) {
     for (let fileName of Object.keys(m)) {
       const file = m[fileName];
+      if (file === undefined) {
+        return;
+      }
       Object.keys(file)
           .map((propName) => propName.substring(propName.lastIndexOf('.') + 1))
           .forEach((propName) => candidates[propName] = true);
     }
   }
 
   setTypeChecker(tc: ts.TypeChecker) { this.tc = tc; }
 
-  maybeHandleCall(c: ts.CallExpression): boolean {
-    if (!this.tc) return false;
-    let {context, symbol} = this.getCallInformation(c);
-    if (!symbol) {
-      // getCallInformation returns a symbol if we understand this call.
-      return false;
-    }
-    let handler = this.getHandler(c, symbol, this.callHandlers);
-    return handler && !handler(c, context);
-  }
-
-  handlePropertyAccess(pa: ts.PropertyAccessExpression): boolean {
-    if (!this.tc) return;
-    let ident = pa.name.text;
-    if (!this.candidateProperties.hasOwnProperty(ident)) return false;
-    let symbol = this.tc.getSymbolAtLocation(pa.name);
-    if (!symbol) {
-      this.reportMissingType(pa, ident);
-      return false;
-    }
-
-    let handler = this.getHandler(pa, symbol, this.propertyHandlers);
-    return handler && !handler(pa);
-  }
-
-  /**
-   * Searches for type references that require extra imports and emits the imports as necessary.
-   */
-  emitExtraImports(sourceFile: ts.SourceFile) {
-    let libraries = <ts.Map<string>>{
-      'XMLHttpRequest': 'dart:html',
-      'KeyboardEvent': 'dart:html',
-      'Uint8Array': 'dart:typed_arrays',
-      'ArrayBuffer': 'dart:typed_arrays',
-      'Promise': 'dart:async',
-    };
-    let emitted: Set = {};
-    this.emitImports(sourceFile, libraries, emitted, sourceFile);
-  }
-
-  private emitImports(
-      n: ts.Node, libraries: ts.Map<string>, emitted: Set, sourceFile: ts.SourceFile): void {
-    if (n.kind === ts.SyntaxKind.TypeReference) {
-      let type = base.ident((<ts.TypeReferenceNode>n).typeName);
-      if (libraries.hasOwnProperty(type)) {
-        let toEmit = libraries[type];
-        if (!emitted[toEmit]) {
-          this.emit(`import "${toEmit}";`);
-          emitted[toEmit] = true;
-        }
-      }
-    }
-
-    n.getChildren(sourceFile)
-        .forEach((child: ts.Node) => this.emitImports(child, libraries, emitted, sourceFile));
-  }
-
   pushTypeParameterNames(n: ts.FunctionLikeDeclaration) {
     if (!n.typeParameters) return;
     this.genericMethodDeclDepth++;
   }
 
   popTypeParameterNames(n: ts.FunctionLikeDeclaration) {
     if (!n.typeParameters) return;
     this.genericMethodDeclDepth--;
   }
 
@@ skipping 10 matching lines @@
             ' used for named parameter definition must be a property';
         this.reportError(decl, msg);
         continue;
       }
       res[sym.name] = <ts.PropertyDeclaration>decl;
     }
     return res;
   }
 
   /**
-   * The Dart Development Compiler (DDC) has a syntax extension that uses comments to emulate
-   * generic methods in Dart. ts2dart has to hack around this and keep track of which type names
-   * in the current scope are actually DDC type parameters and need to be emitted in comments.
+   * The Dart analyzer has a syntax extension that uses comments to emulate
+   * generic methods in Dart. We work around this and keep track of which type
+   * names in the current scope need to be emitted in comments.
    *
-   * TODO(martinprobst): Remove this once the DDC hack has made it into Dart proper.
+   * TODO(jacobr): Remove this once all Dart implementations support generic
+   * methods.
    */
   private isGenericMethodTypeParameterName(name: ts.EntityName): boolean {
     // Avoid checking this unless needed.
     if (this.genericMethodDeclDepth === 0 || !this.tc) return false;
     // Check if the type of the name is a TypeParameter.
     let t = this.tc.getTypeAtLocation(name);
     if (!t || (t.flags & ts.TypeFlags.TypeParameter) === 0) return false;
 
     // Check if the symbol we're looking at is the type parameter.
     let symbol = this.tc.getSymbolAtLocation(name);
     if (symbol !== t.symbol) return false;
 
     // Check that the Type Parameter has been declared by a function declaration.
     return symbol.declarations.some(d => d.parent.kind === ts.SyntaxKind.FunctionDeclaration);
   }
 
+  generateTypeList(types: ts.TypeNode[], seperator = ','): string {
+    return types.map(this.generateDartTypeName.bind(this)).join(seperator);
+  }
+
+  maybeGenerateTypeArguments(n: {typeArguments?: ts.NodeArray<ts.TypeNode>}): string {
+    if (!n.typeArguments) return '';
+    return '<' + this.generateTypeList(n.typeArguments) + '>';
+  }
+
+  generateDartTypeName(node: ts.TypeNode): string {
+    let name: string;
+    let comment: string;
+    if (!node) {
+      return 'dynamic';
+    }
+    switch (node.kind) {
+      case ts.SyntaxKind.TypeQuery:
+        let query = <ts.TypeQueryNode>node;
+        name = 'dynamic';
+        name += '/* Dart does not support TypeQuery: typeof ' + base.ident(query.exprName) + ' */';
+        break;
+      case ts.SyntaxKind.LastTypeNode:
+        let type = (node as ts.ParenthesizedTypeNode).type;
+        if (!type) {
+          // This case occurs for String literal types
+          comment = node.getText();
+          // TODO(jacobr): find a better way to detect string literal types.
+          name = comment[0] === '"' ? 'String' : 'dynamic';
+          break;
+        }
+        return this.generateDartTypeName(type);
+      case ts.SyntaxKind.TypePredicate:
+        return this.generateDartTypeName((node as ts.TypePredicateNode).type);
+      case ts.SyntaxKind.TupleType:
+        let tuple = <ts.TupleTypeNode>node;
+        name = 'List<';
+        let mergedType = new MergedType(this);
+        tuple.elementTypes.forEach((t) => mergedType.merge(t));
+        name += this.generateDartTypeName(mergedType.toTypeNode());
+        name += '>';
+        comment = 'Tuple<' + this.generateTypeList(tuple.elementTypes) + '>';
+        break;
+      case ts.SyntaxKind.UnionType:
+        let union = <ts.UnionTypeNode>node;
+        // TODO(jacobr): this isn't fundamentally JS Interop specific but we
+        // choose to be more aggressive at finding a useful value for the
+        // union when in JS Interop mode while otherwise we expect that union
+        // types will not be used extensively.
+        let simpleType = this.toSimpleDartType(union.types);
+        if (simpleType) {
+          name = this.generateDartTypeName(simpleType);
+        } else {
+          name = 'dynamic';
+        }
+        let types = union.types;
+        comment = this.generateTypeList(types, '|');
+        break;
+      case ts.SyntaxKind.TypePredicate:
+        return this.generateDartTypeName((node as ts.TypePredicateNode).type);
+      case ts.SyntaxKind.TypeReference:
+        let typeRef = <ts.TypeReferenceNode>node;
+        name = this.generateDartName(typeRef.typeName) + this.maybeGenerateTypeArguments(typeRef);
+        break;
+      case ts.SyntaxKind.TypeLiteral:
+        let members = (<ts.TypeLiteralNode>node).members;
+        if (members.length === 1 && members[0].kind === ts.SyntaxKind.IndexSignature) {
+          let indexSig = <ts.IndexSignatureDeclaration>(members[0]);
+          if (indexSig.parameters.length > 1) {
+            this.reportError(indexSig, 'Expected an index signature to have a single parameter');
+          }
+          // Unfortunately for JS interop, we cannot treat JS Objects as Dart
+          // Map objects. We could treat them as JSMap<indexSig.type>
+          // if we define a base JSMap type that is Map like but not actually
+          // a map.
+          name = 'dynamic';
+          comment = 'Map<' + this.generateDartTypeName(indexSig.parameters[0].type) + ',' +
+              this.generateDartTypeName(indexSig.type) + '>';
+        } else {
+          name = 'dynamic';
+          comment = node.getText();
+        }
+        break;
+      case ts.SyntaxKind.FunctionType:
+        let callSignature = <ts.FunctionOrConstructorTypeNode>node;
+        let parameters = callSignature.parameters;
+
+        // Use a function signature from package:func where possible.
+        let numOptional = numOptionalParameters(parameters);
+        let isVoid = callSignature.type && callSignature.type.kind === ts.SyntaxKind.VoidKeyword;
+        if (parameters.length <= MAX_DART_FUNC_ACTION_PARAMETERS &&
+            numOptional <= MAX_DART_FUNC_ACTION_PARAMETERS_OPTIONAL && !hasVarArgs(parameters)) {
+          this.emitImport('package:func/func.dart');
+          let typeDefName = (isVoid) ? 'VoidFunc' : 'Func';
+          typeDefName += parameters.length;
+          if (numOptional > 0) {
+            typeDefName += 'Opt' + numOptional;
+          }
+          name = typeDefName;
+          let numArgs = parameters.length + (isVoid ? 0 : 1);
+          if (numArgs > 0) {
+            name += '<';
+          }
+          let isFirst = true;
+          for (let i = 0; i < parameters.length; ++i) {
+            if (isFirst) {
+              isFirst = false;
+            } else {
+              name += ', ';
+            }
+            name += this.generateDartTypeName(parameters[i].type);
+          }
+          if (!isVoid) {
+            if (!isFirst) {
+              name += ', ';
+            }
+            name += this.generateDartTypeName(callSignature.type);
+          }
+          if (numArgs > 0) {
+            name += '>';
+          }
+        } else {
+          name = 'Function';
+          if (node.getSourceFile()) {
+            comment = node.getText();
+          }
+        }
+        break;
+      case ts.SyntaxKind.ArrayType:
+        name = 'List' +
+            '<' + this.generateDartTypeName((<ts.ArrayTypeNode>node).elementType) + '>';
+        break;
+      case ts.SyntaxKind.NumberKeyword:
+        name = 'num';
+        break;
+      case ts.SyntaxKind.StringLiteral:
+      case ts.SyntaxKind.StringKeyword:
+        name = 'String';
+        break;
+      case ts.SyntaxKind.VoidKeyword:
+        name = 'void';
+        break;
+      case ts.SyntaxKind.BooleanKeyword:
+        name = 'bool';
+        break;
+      case ts.SyntaxKind.AnyKeyword:
+        name = 'dynamic';
+        break;
+      default:
+        this.reportError(node, 'Unexpected TypeNode kind');
+    }
+    if (name == null) {
+      name = 'XXX NULLNAME';
+    }
+
+    name = name.trim();
+
+    if (comment) {
+      name = name + '/*' + comment + '*/';
+    }
+    return name;
+  }
+
   visitTypeName(typeName: ts.EntityName) {
     if (typeName.kind !== ts.SyntaxKind.Identifier) {
       this.visit(typeName);
       return;
     }
     let ident = base.ident(typeName);
     if (this.isGenericMethodTypeParameterName(typeName)) {
       // DDC generic methods hack - all names that are type parameters to generic methods have to be
       // emitted in comments.
       this.emit('dynamic/*=');
       this.emit(ident);
       this.emit('*/');
       return;
     }
 
-    if (this.candidateTypes.hasOwnProperty(ident) && this.tc) {
-      let symbol = this.tc.getSymbolAtLocation(typeName);
-      if (!symbol) {
-        this.reportMissingType(typeName, ident);
-        return;
-      }
-      let fileAndName = this.getFileAndName(typeName, symbol);
-      if (fileAndName) {
-        let fileSubs = this.TS_TO_DART_TYPENAMES[fileAndName.fileName];
-        if (fileSubs && fileSubs.hasOwnProperty(fileAndName.qname)) {
-          this.emit(fileSubs[fileAndName.qname]);
-          return;
-        }
-      }
-    }
-    this.emit(ident);
-  }
-
-  shouldEmitNew(c: ts.CallExpression): boolean {
-    if (!this.tc) return true;
-
-    let ci = this.getCallInformation(c);
-    let symbol = ci.symbol;
-    // getCallInformation returns a symbol if we understand this call.
-    if (!symbol) return true;
-
-    let loc = this.getFileAndName(c, symbol);
-    if (!loc) return true;
-    let {fileName, qname} = loc;
-    let fileSubs = this.callHandlerReplaceNew[fileName];
-    if (!fileSubs) return true;
-    return !fileSubs[qname];
-  }
-
-  private getCallInformation(c: ts.CallExpression): {context?: ts.Expression, symbol?: ts.Symbol} {
-    let symbol: ts.Symbol;
-    let context: ts.Expression;
-    let ident: string;
-    let expr = c.expression;
-
-    if (expr.kind === ts.SyntaxKind.Identifier) {
-      // Function call.
-      ident = base.ident(expr);
-      if (!this.candidateProperties.hasOwnProperty(ident)) return {};
-      symbol = this.tc.getSymbolAtLocation(expr);
-      if (FACADE_DEBUG) console.error('s:', symbol);
-
-      if (!symbol) {
-        this.reportMissingType(c, ident);
-        return {};
-      }
-
-      context = null;
-    } else if (expr.kind === ts.SyntaxKind.PropertyAccessExpression) {
-      // Method call.
-      let pa = <ts.PropertyAccessExpression>expr;
-      ident = base.ident(pa.name);
-      if (!this.candidateProperties.hasOwnProperty(ident)) return {};
-
-      symbol = this.tc.getSymbolAtLocation(pa);
-      if (FACADE_DEBUG) console.error('s:', symbol);
-
-      // Error will be reported by PropertyAccess handling below.
-      if (!symbol) return {};
-
-      context = pa.expression;
-    }
-    return {context, symbol};
-  }
-
-  private getHandler<T>(n: ts.Node, symbol: ts.Symbol, m: ts.Map<ts.Map<T>>): T {
-    let loc = this.getFileAndName(n, symbol);
-    if (!loc) return null;
-    let {fileName, qname} = loc;
-    let fileSubs = m[fileName];
-    if (!fileSubs) return null;
-    return fileSubs[qname];
-  }
-
-  private getFileAndName(n: ts.Node, originalSymbol: ts.Symbol): {fileName: string, qname: string} {
-    let symbol = originalSymbol;
-    while (symbol.flags & ts.SymbolFlags.Alias) symbol = this.tc.getAliasedSymbol(symbol);
+    let custom = this.lookupCustomDartTypeName(<ts.Identifier>typeName);
+    if (custom) {
+      if (custom.comment) {
+        this.emit('/*=' + custom.comment + '*/');
+      }
+      this.emit(custom.name);
+    } else {
+      this.visit(typeName);
+    }
+  }
+
+  getSymbolDeclaration(symbol: ts.Symbol, n?: ts.Node): ts.Declaration {
+    if (!symbol) return null;
     let decl = symbol.valueDeclaration;
     if (!decl) {
       // In the case of a pure declaration with no assignment, there is no value declared.
       // Just grab the first declaration, hoping it is declared once.
       if (!symbol.declarations || symbol.declarations.length === 0) {
-        this.reportError(n, 'no declarations for symbol ' + originalSymbol.name);
+        this.reportError(n, 'no declarations for symbol ' + symbol.name);
+        return;
+      }
+      decl = symbol.declarations[0];
+    }
+    return decl;
+  }
+
+  generateDartName(identifier: ts.EntityName): string {
+    let ret = this.lookupCustomDartTypeName(identifier);
+    if (ret) {
+      // TODO(jacobr): reduce the number of times we write this pattern.
+      if (ret.comment) {
+        return ret.name + '/*=' + ret.comment + '*/';
+      } else {
+        return ret.name;
+      }
+    }
+    // TODO(jacobr): handle library import prefixes better. This generally works
+    // but is somewhat fragile.
+    return base.ident(identifier);
+  }
+
+  /**
+   * Returns null if declaration cannot be found or is not valid in Dart.
+   */
+  getDeclaration(identifier: ts.EntityName): ts.Declaration {
+    let symbol: ts.Symbol;
+    if (!this.tc) return null;
+
+    symbol = this.tc.getSymbolAtLocation(identifier);
+    let declaration = this.getSymbolDeclaration(symbol, identifier);
+    if (symbol && symbol.flags & ts.SymbolFlags.TypeParameter) {
+      let kind = declaration.parent.kind;
+      // Only kinds of TypeParameters supported by Dart.
+      if (kind !== ts.SyntaxKind.ClassDeclaration && kind !== ts.SyntaxKind.InterfaceDeclaration) {
         return null;
       }
-      decl = symbol.declarations[0];
-    }
+    }
+    return declaration;
+  }
+
+  /**
+   * Returns a custom Dart type name or null if the type isn't a custom Dart
+   * type.
+   */
+  lookupCustomDartTypeName(identifier: ts.EntityName):
+      {name?: string, comment?: string, keep?: boolean} {
+    let ident = base.ident(identifier);
+    let symbol: ts.Symbol;
+    if (!this.tc) return null;
+
+    symbol = this.tc.getSymbolAtLocation(identifier);
+    let declaration = this.getSymbolDeclaration(symbol, identifier);
+    if (symbol && symbol.flags & ts.SymbolFlags.TypeParameter) {
+      let kind = declaration.parent.kind;
+      // Only kinds of TypeParameters supported by Dart.
+      if (kind !== ts.SyntaxKind.ClassDeclaration && kind !== ts.SyntaxKind.InterfaceDeclaration) {
+        return {name: 'dynamic', comment: ident};
+      }
+    }
+
+    if (this.candidateTypes.hasOwnProperty(ident)) {
+      if (!symbol) {
+        return null;
+      }
+
+      let fileAndName = this.getFileAndName(identifier, symbol);
+
+      if (fileAndName) {
+        let fileSubs = TS_TO_DART_TYPENAMES[fileAndName.fileName];
+        if (fileSubs) {
+          let dartBrowserType = DART_LIBRARIES_FOR_BROWSER_TYPES.hasOwnProperty(fileAndName.qname);
+          if (dartBrowserType) {
+            this.emitImport(DART_LIBRARIES_FOR_BROWSER_TYPES[fileAndName.qname]);
+          }
+          if (fileSubs.hasOwnProperty(fileAndName.qname)) {
+            return {name: fileSubs[fileAndName.qname]};
+          }
+          if (dartBrowserType) {
+            // Not a rename but has a dart core libraries definition.
+            return {name: fileAndName.qname};
+          }
+        }
+      }
+    }
+    if (symbol) {
+      if (symbol.flags & ts.SymbolFlags.Enum) {
+        // We can't treat JavaScript enums as Dart enums in this case.
+        return {name: 'num', comment: ident};
+      }
+      // TODO(jacobr): we could choose to only support type alais declarations
+      // for JS interop but it seems handling type alaises is generally helpful
+      // without much risk of generating confusing Dart code.
+      if (declaration.kind === ts.SyntaxKind.TypeAliasDeclaration) {
+        let alias = <ts.TypeAliasDeclaration>declaration;
+        if (alias.typeParameters) {
+          // We can handle this case but currently do not.
+          this.reportError(declaration, 'Type parameters for type alaises are not supported');
+        }
+        return {name: this.generateDartTypeName(alias.type)};
+      }
+
+      let kind = declaration.kind;
+      if (kind === ts.SyntaxKind.ClassDeclaration || kind === ts.SyntaxKind.InterfaceDeclaration ||
+          kind === ts.SyntaxKind.VariableDeclaration ||
+          kind === ts.SyntaxKind.PropertyDeclaration ||
+          kind === ts.SyntaxKind.FunctionDeclaration) {
+        let name = this.nameRewriter.lookupName(<base.NamedDeclaration>declaration, identifier);
+        if (kind === ts.SyntaxKind.InterfaceDeclaration &&
+            base.isFunctionTypedefLikeInterface(<ts.InterfaceDeclaration>declaration) &&
+            base.getAncestor(identifier, ts.SyntaxKind.HeritageClause)) {
+          // TODO(jacobr): we need to specify a specific call method for this
+          // case if we want to get the most from Dart type checking.
+          return {name: 'Function', comment: name};
+        }
+        return {name: name, keep: true};
+      }
+    }
+    return null;
+  }
+
+  // TODO(jacobr): performance of this method could easily be optimized.
+  /**
+   * This method works around the lack of Dart support for union types
+   * generating a valid Dart type that satisfies all the types passed in.
+   */
+  toSimpleDartType(types: Array<ts.TypeNode>) {
+    // We use MergeType to ensure that we have already deduped types that are
+    // equivalent even if they aren't obviously identical.
+    // MergedType will also follow typed aliases, etc which allows us to avoid
+    // including that logic here as well.
+    let mergedType = new MergedType(this);
+    types.forEach((type) => { mergedType.merge(type); });
+    let merged = mergedType.toTypeNode();
+    if (merged.kind === ts.SyntaxKind.UnionType) {
+      // For union types find a Dart type that satisfies all the types.
+      types = (<ts.UnionTypeNode>merged).types;
+      /**
+       * Generate a common base type for an array of types.
+       * The implemented is currently incomplete often returning null when there
+       * might really be a valid common base type.
+       */
+      let common: ts.TypeNode = types[0];
+      for (let i = 1; i < types.length && common != null; ++i) {
+        let type = types[i];
+        if (common !== type) {
+          if (base.isCallableType(common, this.tc) && base.isCallableType(type, this.tc)) {
+            // Fall back to a generic Function type if both types are Function.
+            let fn = <ts.FunctionOrConstructorTypeNode>ts.createNode(ts.SyntaxKind.FunctionType);
+            fn.parameters = <ts.NodeArray<ts.ParameterDeclaration>>[];
+            let parameter = <ts.ParameterDeclaration>ts.createNode(ts.SyntaxKind.Parameter);
+            parameter.dotDotDotToken = ts.createNode(ts.SyntaxKind.DotDotDotToken);
+            let name = <ts.Identifier>ts.createNode(ts.SyntaxKind.Identifier);
+            name.text = 'args';
+            fn.parameters.push(parameter);
+            common = fn;
+          } else {
+            switch (type.kind) {
+              case ts.SyntaxKind.ArrayType:
+                let array = <ts.ArrayTypeNode>ts.createNode(ts.SyntaxKind.ArrayType);
+                array.elementType = this.toSimpleDartType([
+                  (common as ts.ArrayTypeNode).elementType, (type as ts.ArrayTypeNode).elementType
+                ]);
+                common = array;
+                break;
+              // case ts.SyntaxKind
+              case ts.SyntaxKind.TypeReference:
+                if (common.kind !== ts.SyntaxKind.TypeReference) {
+                  return null;
+                }
+                common = this.commonSupertype(common, type);
+                break;
+
+              default:
+                return null;
+            }
+          }
+        }
+      }
+      return common;
+    }
+    return merged;
+  }
+
+  toTypeNode(type: ts.Type): ts.TypeNode {
+    if (!type) return null;
+    let symbol = type.getSymbol();
+    if (!symbol) return null;
+
+    let referenceType = <ts.TypeReferenceNode>ts.createNode(ts.SyntaxKind.TypeReference);
+    // TODO(jacobr): property need to prefix the name better.
+    referenceType.typeName = this.createEntityName(symbol);
+    referenceType.typeName.parent = referenceType;
+    return referenceType;
+  }
+
+  createEntityName(symbol: ts.Symbol): ts.EntityName {
+    let parts = this.tc.getFullyQualifiedName(symbol).split('.');
+    let identifier = <ts.Identifier>ts.createNode(ts.SyntaxKind.Identifier);
+    identifier.text = parts[parts.length - 1];
+    // TODO(jacobr): do we need to include all parts in the entity name?
+    return identifier;
+  }
+
+  safeGetBaseTypes(type: ts.InterfaceType): ts.ObjectType[] {
+    // For an unknown, calling TypeChecker.getBaseTypes on an interface
+    // that is a typedef like interface causes the typescript compiler to stack
+    // overflow. Not sure if this is a bug in the typescript compiler or I am
+    // missing something obvious.
+    let declaration = base.getDeclaration(type) as ts.InterfaceDeclaration;
+    if (base.isFunctionTypedefLikeInterface(declaration)) {
+      return [];
+    }
+    return this.tc.getBaseTypes(type);
+  }
+
+  // TODO(jacobr): all of these subtype checks are fragile and are likely a
+  // mistake. We would be better off handling subtype relationships in Dart
+  // where we could reuse an existing Dart type system.
+  checkTypeSubtypeOf(source: ts.Type, target: ts.Type) {
+    if (source === target) return true;
+    if (!(source.flags & ts.TypeFlags.Interface)) return false;
+    let baseTypes = this.safeGetBaseTypes(source as ts.InterfaceType);
+    for (let i = 0; i < baseTypes.length; ++i) {
+      if (baseTypes[i] === target) return true;
+    }
+    return false;
+  }
+
+  commonSupertype(nodeA: ts.TypeNode, nodeB: ts.TypeNode): ts.TypeNode {
+    if (nodeA == null || nodeB == null) return null;
+    return this.toTypeNode(this.getCommonSupertype(
+        this.tc.getTypeAtLocation(nodeA), this.tc.getTypeAtLocation(nodeB)));
+  }
+
+  getCommonSupertype(a: ts.Type, b: ts.Type): ts.Type {
+    if (a === b) return a;
+
+    if (!(a.flags & ts.TypeFlags.Interface) || !(b.flags & ts.TypeFlags.Interface)) {
+      return null;
+    }
+
+    let bestCommonSuperType: ts.Type = null;
+    let candidatesA = this.safeGetBaseTypes(a as ts.InterfaceType);
+    candidatesA.push(a);
+
+    for (let i = 0; i < candidatesA.length; ++i) {
+      let type = candidatesA[i];
+      if (this.checkTypeSubtypeOf(b, type)) {
+        if (!bestCommonSuperType || this.checkTypeSubtypeOf(bestCommonSuperType, type)) {
+          bestCommonSuperType = type;
+        }
+      }
+    }
+    return bestCommonSuperType;
+  }
+
+  private getFileAndName(n: ts.Node, originalSymbol: ts.Symbol): {fileName: string, qname: string} {
+    let symbol = originalSymbol;
+    while (symbol.flags & ts.SymbolFlags.Alias) symbol = this.tc.getAliasedSymbol(symbol);
+    let decl = this.getSymbolDeclaration(symbol, n);
 
     const fileName = decl.getSourceFile().fileName;
     const canonicalFileName = this.getRelativeFileName(fileName)
                                   .replace(/(\.d)?\.ts$/, '')
                                   .replace(FACADE_NODE_MODULES_PREFIX, '')
                                   .replace(this.typingsRootRegex, '');
 
     let qname = this.tc.getFullyQualifiedName(symbol);
     // Some Qualified Names include their file name. Might be a bug in TypeScript,
     // for the time being just special case.
     if (symbol.flags & (ts.SymbolFlags.Class | ts.SymbolFlags.Function | ts.SymbolFlags.Variable)) {
       qname = symbol.getName();
     }
     if (FACADE_DEBUG) console.error('fn:', fileName, 'cfn:', canonicalFileName, 'qn:', qname);
     return {fileName: canonicalFileName, qname};
   }
-
-  private isNamedType(node: ts.Node, fileName: string, qname: string): boolean {
-    let symbol = this.tc.getTypeAtLocation(node).getSymbol();
-    if (!symbol) return false;
-    let actual = this.getFileAndName(node, symbol);
-    if (fileName === 'lib' && !(actual.fileName === 'lib' || actual.fileName === 'lib.es6')) {
-      return false;
-    } else {
-      if (fileName !== actual.fileName) return false;
-    }
-    return qname === actual.qname;
-  }
-
-  private reportMissingType(n: ts.Node, ident: string) {
-    this.reportError(
-        n, `Untyped property access to "${ident}" which could be ` + `a special ts2dart builtin. ` +
-            `Please add type declarations to disambiguate.`);
-  }
-
-  isInsideConstExpr(node: ts.Node): boolean {
-    return this.isConstCall(
-        <ts.CallExpression>this.getAncestor(node, ts.SyntaxKind.CallExpression));
-  }
-
-  isConstCall(node: ts.Expression): boolean {
-    return node && node.kind === ts.SyntaxKind.CallExpression &&
-        base.ident((<ts.CallExpression>node).expression) === 'CONST_EXPR';
-  }
-
-  private emitMethodCall(name: string, args?: ts.Expression[]) {
-    this.emit('.');
-    this.emitCall(name, args);
-  }
-
-  private emitCall(name: string, args?: ts.Expression[]) {
-    this.emit(name);
-    this.emit('(');
-    if (args) this.visitList(args);
-    this.emit(')');
-  }
-
-  private stdlibTypeReplacements: ts.Map<string> = {
-    'Date': 'DateTime',
-    'Array': 'List',
-    'XMLHttpRequest': 'HttpRequest',
-    'Uint8Array': 'Uint8List',
-    'ArrayBuffer': 'ByteBuffer',
-    'Promise': 'Future',
-
-    // Dart has two different incompatible DOM APIs
-    // https://github.com/angular/angular/issues/2770
-    'Node': 'dynamic',
-    'Text': 'dynamic',
-    'Element': 'dynamic',
-    'Event': 'dynamic',
-    'HTMLElement': 'dynamic',
-    'HTMLAnchorElement': 'dynamic',
-    'HTMLStyleElement': 'dynamic',
-    'HTMLInputElement': 'dynamic',
-    'HTMLDocument': 'dynamic',
-    'History': 'dynamic',
-    'Location': 'dynamic',
-  };
-
-  private TS_TO_DART_TYPENAMES: ts.Map<ts.Map<string>> = {
-    'lib': this.stdlibTypeReplacements,
-    'lib.es6': this.stdlibTypeReplacements,
-    'angular2/src/facade/lang': {'Date': 'DateTime'},
-
-    'rxjs/Observable': {'Observable': 'Stream'},
-    'es6-promise/es6-promise': {'Promise': 'Future'},
-    'es6-shim/es6-shim': {'Promise': 'Future'},
-  };
-
-  private es6Promises: ts.Map<CallHandler> = {
-    'Promise.catch': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emit('.catchError(');
-      this.visitList(c.arguments);
-      this.emit(')');
-    },
-    'Promise.then': (c: ts.CallExpression, context: ts.Expression) => {
-      // then() in Dart doesn't support 2 arguments.
-      this.visit(context);
-      this.emit('.then(');
-      this.visit(c.arguments[0]);
-      this.emit(')');
-      if (c.arguments.length > 1) {
-        this.emit('.catchError(');
-        this.visit(c.arguments[1]);
-        this.emit(')');
-      }
-    },
-    'Promise': (c: ts.CallExpression, context: ts.Expression) => {
-      if (c.kind !== ts.SyntaxKind.NewExpression) return true;
-      this.assert(c, c.arguments.length === 1, 'Promise construction must take 2 arguments.');
-      this.assert(
-          c, c.arguments[0].kind === ts.SyntaxKind.ArrowFunction ||
-              c.arguments[0].kind === ts.SyntaxKind.FunctionExpression,
-          'Promise argument must be a function expression (or arrow function).');
-      let callback: ts.FunctionLikeDeclaration;
-      if (c.arguments[0].kind === ts.SyntaxKind.ArrowFunction) {
-        callback = <ts.FunctionLikeDeclaration>(<ts.ArrowFunction>c.arguments[0]);
-      } else if (c.arguments[0].kind === ts.SyntaxKind.FunctionExpression) {
-        callback = <ts.FunctionLikeDeclaration>(<ts.FunctionExpression>c.arguments[0]);
-      }
-      this.assert(
-          c, callback.parameters.length > 0 && callback.parameters.length < 3,
-          'Promise executor must take 1 or 2 arguments (resolve and reject).');
-
-      const completerVarName = this.uniqueId('completer');
-      this.assert(
-          c, callback.parameters[0].name.kind === ts.SyntaxKind.Identifier,
-          'First argument of the Promise executor is not a straight parameter.');
-      let resolveParameterIdent = <ts.Identifier>(callback.parameters[0].name);
-
-      this.emit('(() {');  // Create a new scope.
-      this.emit(`Completer ${completerVarName} = new Completer();`);
-      this.emit('var');
-      this.emit(resolveParameterIdent.text);
-      this.emit(`= ${completerVarName}.complete;`);
-
-      if (callback.parameters.length === 2) {
-        this.assert(
-            c, callback.parameters[1].name.kind === ts.SyntaxKind.Identifier,
-            'First argument of the Promise executor is not a straight parameter.');
-        let rejectParameterIdent = <ts.Identifier>(callback.parameters[1].name);
-        this.emit('var');
-        this.emit(rejectParameterIdent.text);
-        this.emit(`= ${completerVarName}.completeError;`);
-      }
-      this.emit('(()');
-      this.visit(callback.body);
-      this.emit(')();');
-      this.emit(`return ${completerVarName}.future;`);
-      this.emit('})()');
-    },
-  };
-
-  private stdlibHandlers: ts.Map<CallHandler> = merge(this.es6Promises, {
-    'Array.push': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emitMethodCall('add', c.arguments);
-    },
-    'Array.pop': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emitMethodCall('removeLast');
-    },
-    'Array.shift': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emit('. removeAt ( 0 )');
-    },
-    'Array.unshift': (c: ts.CallExpression, context: ts.Expression) => {
-      this.emit('(');
-      this.visit(context);
-      if (c.arguments.length === 1) {
-        this.emit('.. insert ( 0,');
-        this.visit(c.arguments[0]);
-        this.emit(') ) . length');
-      } else {
-        this.emit('.. insertAll ( 0, [');
-        this.visitList(c.arguments);
-        this.emit(']) ) . length');
-      }
-    },
-    'Array.map': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emitMethodCall('map', c.arguments);
-      this.emitMethodCall('toList');
-    },
-    'Array.filter': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emitMethodCall('where', c.arguments);
-      this.emitMethodCall('toList');
-    },
-    'Array.some': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emitMethodCall('any', c.arguments);
-    },
-    'Array.slice': (c: ts.CallExpression, context: ts.Expression) => {
-      this.emitCall('ListWrapper.slice', [context, ...c.arguments]);
-    },
-    'Array.splice': (c: ts.CallExpression, context: ts.Expression) => {
-      this.emitCall('ListWrapper.splice', [context, ...c.arguments]);
-    },
-    'Array.concat': (c: ts.CallExpression, context: ts.Expression) => {
-      this.emit('( new List . from (');
-      this.visit(context);
-      this.emit(')');
-      c.arguments.forEach(arg => {
-        if (!this.isNamedType(arg, 'lib', 'Array')) {
-          this.reportError(arg, 'Array.concat only takes Array arguments');
-        }
-        this.emit('.. addAll (');
-        this.visit(arg);
-        this.emit(')');
-      });
-      this.emit(')');
-    },
-    'Array.join': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      if (c.arguments.length) {
-        this.emitMethodCall('join', c.arguments);
-      } else {
-        this.emit('. join ( "," )');
-      }
-    },
-    'Array.reduce': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-
-      if (c.arguments.length >= 2) {
-        this.emitMethodCall('fold', [c.arguments[1], c.arguments[0]]);
-      } else {
-        this.emit('. fold ( null ,');
-        this.visit(c.arguments[0]);
-        this.emit(')');
-      }
-    },
-    'ArrayConstructor.isArray': (c: ts.CallExpression, context: ts.Expression) => {
-      this.emit('( (');
-      this.visitList(c.arguments);  // Should only be 1.
-      this.emit(')');
-      this.emit('is List');
-      this.emit(')');
-    },
-    'Console.log': (c: ts.CallExpression, context: ts.Expression) => {
-      this.emit('print(');
-      if (c.arguments.length === 1) {
-        this.visit(c.arguments[0]);
-      } else {
-        this.emit('[');
-        this.visitList(c.arguments);
-        this.emit('].join(" ")');
-      }
-      this.emit(')');
-    },
-    'RegExp.exec': (c: ts.CallExpression, context: ts.Expression) => {
-      if (context.kind !== ts.SyntaxKind.RegularExpressionLiteral) {
-        // Fail if the exec call isn't made directly on a regexp literal.
-        // Multiple exec calls on the same global regexp have side effects
-        // (each return the next match), which we can't reproduce with a simple
-        // Dart RegExp (users should switch to some facade / wrapper instead).
-        this.reportError(
-            c, 'exec is only supported on regexp literals, ' +
-                'to avoid side-effect of multiple calls on global regexps.');
-      }
-      if (c.parent.kind === ts.SyntaxKind.ElementAccessExpression) {
-        // The result of the exec call is used for immediate indexed access:
-        // this use-case can be accommodated by RegExp.firstMatch, which returns
-        // a Match instance with operator[] which returns groups (special index
-        // 0 returns the full text of the match).
-        this.visit(context);
-        this.emitMethodCall('firstMatch', c.arguments);
-      } else {
-        // In the general case, we want to return a List. To transform a Match
-        // into a List of its groups, we alias it in a local closure that we
-        // call with the Match value. We are then able to use the group method
-        // to generate a List large enough to hold groupCount groups + the
-        // full text of the match at special group index 0.
-        this.emit('((match) => new List.generate(1 + match.groupCount, match.group))(');
-        this.visit(context);
-        this.emitMethodCall('firstMatch', c.arguments);
-        this.emit(')');
-      }
-    },
-    'RegExp.test': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emitMethodCall('hasMatch', c.arguments);
-    },
-    'String.substr': (c: ts.CallExpression, context: ts.Expression) => {
-      this.reportError(
-          c, 'substr is unsupported, use substring (but beware of the different semantics!)');
-      this.visit(context);
-      this.emitMethodCall('substr', c.arguments);
-    },
-  });
-
-  private es6Collections: ts.Map<CallHandler> = {
-    'Map.set': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emit('[');
-      this.visit(c.arguments[0]);
-      this.emit(']');
-      this.emit('=');
-      this.visit(c.arguments[1]);
-    },
-    'Map.get': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emit('[');
-      this.visit(c.arguments[0]);
-      this.emit(']');
-    },
-    'Map.has': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emitMethodCall('containsKey', c.arguments);
-    },
-    'Map.delete': (c: ts.CallExpression, context: ts.Expression) => {
-      // JS Map.delete(k) returns whether k was present in the map,
-      // convert to:
-      // (Map.containsKey(k) && (Map.remove(k) !== null || true))
-      // (Map.remove(k) !== null || true) is required to always returns true
-      // when Map.containsKey(k)
-      this.emit('(');
-      this.visit(context);
-      this.emitMethodCall('containsKey', c.arguments);
-      this.emit('&& (');
-      this.visit(context);
-      this.emitMethodCall('remove', c.arguments);
-      this.emit('!= null || true ) )');
-    },
-    'Map.forEach': (c: ts.CallExpression, context: ts.Expression) => {
-      let cb: any;
-      let params: any;
-
-      switch (c.arguments[0].kind) {
-        case ts.SyntaxKind.FunctionExpression:
-          cb = <ts.FunctionExpression>(c.arguments[0]);
-          params = cb.parameters;
-          if (params.length !== 2) {
-            this.reportError(c, 'Map.forEach callback requires exactly two arguments');
-            return;
-          }
-          this.visit(context);
-          this.emit('. forEach ( (');
-          this.visit(params[1]);
-          this.emit(',');
-          this.visit(params[0]);
-          this.emit(')');
-          this.visit(cb.body);
-          this.emit(')');
-          break;
-
-        case ts.SyntaxKind.ArrowFunction:
-          cb = <ts.ArrowFunction>(c.arguments[0]);
-          params = cb.parameters;
-          if (params.length !== 2) {
-            this.reportError(c, 'Map.forEach callback requires exactly two arguments');
-            return;
-          }
-          this.visit(context);
-          this.emit('. forEach ( (');
-          this.visit(params[1]);
-          this.emit(',');
-          this.visit(params[0]);
-          this.emit(')');
-          if (cb.body.kind !== ts.SyntaxKind.Block) {
-            this.emit('=>');
-          }
-          this.visit(cb.body);
-          this.emit(')');
-          break;
-
-        default:
-          this.visit(context);
-          this.emit('. forEach ( ( k , v ) => (');
-          this.visit(c.arguments[0]);
-          this.emit(') ( v , k ) )');
-          break;
-      }
-    },
-    'Array.find': (c: ts.CallExpression, context: ts.Expression) => {
-      this.visit(context);
-      this.emit('. firstWhere (');
-      this.visit(c.arguments[0]);
-      this.emit(', orElse : ( ) => null )');
-    },
-  };
-
-  private callHandlerReplaceNew: ts.Map<ts.Map<boolean>> = {
-    'es6-promise/es6-promise': {'Promise': true},
-    'es6-shim/es6-shim': {'Promise': true},
-  };
-
-  private callHandlers: ts.Map<ts.Map<CallHandler>> = {
-    'lib': this.stdlibHandlers,
-    'lib.es6': this.stdlibHandlers,
-    'es6-promise/es6-promise': this.es6Promises,
-    'es6-shim/es6-shim': merge(this.es6Promises, this.es6Collections),
-    'es6-collections/es6-collections': this.es6Collections,
-    'angular2/manual_typings/globals': this.es6Collections,
-    'angular2/src/facade/collection': {
-      'Map': (c: ts.CallExpression, context: ts.Expression): boolean => {
-        // The actual Map constructor is special cased for const calls.
-        if (!this.isInsideConstExpr(c)) return true;
-        if (c.arguments.length) {
-          this.reportError(c, 'Arguments on a Map constructor in a const are unsupported');
-        }
-        if (c.typeArguments) {
-          this.emit('<');
-          this.visitList(c.typeArguments);
-          this.emit('>');
-        }
-        this.emit('{ }');
-        return false;
-      },
-    },
-    'angular2/src/core/di/forward_ref': {
-      'forwardRef': (c: ts.CallExpression, context: ts.Expression) => {
-        // The special function forwardRef translates to an unwrapped value in Dart.
-        const callback = <ts.FunctionExpression>c.arguments[0];
-        if (callback.kind !== ts.SyntaxKind.ArrowFunction) {
-          this.reportError(c, 'forwardRef takes only arrow functions');
-          return;
-        }
-        this.visit(callback.body);
-      },
-    },
-    'angular2/src/facade/lang': {
-      'CONST_EXPR': (c: ts.CallExpression, context: ts.Expression) => {
-        // `const` keyword is emitted in the array literal handling, as it needs to be transitive.
-        this.visitList(c.arguments);
-      },
-      'normalizeBlank': (c: ts.CallExpression, context: ts.Expression) => {
-        // normalizeBlank is a noop in Dart, so erase it.
-        this.visitList(c.arguments);
-      },
-    },
-  };
-
-  private es6CollectionsProp: ts.Map<PropertyHandler> = {
-    'Map.size': (p: ts.PropertyAccessExpression) => {
-      this.visit(p.expression);
-      this.emit('.');
-      this.emit('length');
-    },
-  };
-  private es6PromisesProp: ts.Map<PropertyHandler> = {
-    'resolve': (p: ts.PropertyAccessExpression) => {
-      this.visit(p.expression);
-      this.emit('.value');
-    },
-    'reject': (p: ts.PropertyAccessExpression) => {
-      this.visit(p.expression);
-      this.emit('.error');
-    },
-  };
-
-  private propertyHandlers: ts.Map<ts.Map<PropertyHandler>> = {
-    'es6-shim/es6-shim': this.es6CollectionsProp,
-    'es6-collections/es6-collections': this.es6CollectionsProp,
-    'es6-promise/es6-promise': this.es6PromisesProp,
-  };
 }