From c5ec461c16adfca1450236093604e27d3ac9001d Mon Sep 17 00:00:00 2001
From: Peter Burns <rictic@google.com>
Date: Fri, 26 Jan 2018 16:52:40 -0800
Subject: [PATCH 1/3] Implement strict initialization.

---
 package-lock.json                             |  6 +++---
 package.json                                  |  2 +-
 src/analysis-format/generate-analysis.ts      |  2 +-
 src/core/analysis-context.ts                  | 14 ++++++-------
 src/core/utils.ts                             |  4 ++--
 src/css/css-document.ts                       |  8 ++------
 src/css/css-parser.ts                         |  3 ++-
 src/html/html-document.ts                     |  6 +-----
 src/html/html-parser.ts                       | 20 +++++++++++--------
 src/html/html-script-tag.ts                   |  4 ++--
 src/javascript/javascript-document.ts         |  4 ++--
 src/javascript/javascript-parser.ts           | 10 ++++++----
 src/json/json-document.ts                     |  8 ++------
 src/json/json-parser.ts                       |  3 ++-
 src/model/document.ts                         |  4 ++--
 src/model/element-base.ts                     | 12 +++++------
 src/model/element-mixin.ts                    |  1 +
 src/model/element.ts                          |  3 +--
 src/model/inline-document.ts                  |  6 ++++--
 src/model/reference.ts                        |  1 +
 src/parser/document.ts                        |  8 ++++----
 src/parser/parser.ts                          |  2 +-
 src/polymer/behavior-scanner.ts               |  3 ++-
 src/polymer/behavior.ts                       |  5 +----
 src/polymer/polymer-element-mixin.ts          |  5 +++--
 src/polymer/polymer-element.ts                |  5 ++++-
 src/test/parser/document_test.ts              |  6 +++---
 src/test/polymer/behavior-scanner_test.ts     |  3 +++
 .../typescript/typescript-analyzer_test.ts    |  4 ++--
 src/test/url-loader/multi-url-loader_test.ts  | 10 ++--------
 .../url-loader/prefixed-url-loader_test.ts    |  9 ++-------
 src/typescript/typescript-document.ts         | 10 ++--------
 src/typescript/typescript-preparser.ts        |  3 ++-
 tsconfig.json                                 |  1 +
 34 files changed, 92 insertions(+), 103 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 8d5825f9..092d179b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4686,9 +4686,9 @@
       "dev": true
     },
     "typescript": {
-      "version": "2.6.2",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-2.6.2.tgz",
-      "integrity": "sha1-PFtv1/beCRQmkCfwPAlGdY92c6Q=",
+      "version": "2.8.0-dev.20180125",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-2.8.0-dev.20180125.tgz",
+      "integrity": "sha512-D5kzJ/iG752X4Nko+Ga3B9Iu/96qj2MIiqAhDIVuzMIdVp1Hi7MHrDqzaU/FjLCiiq2OuhBdIRqkk3Vr5a57HA==",
       "dev": true
     },
     "typescript-json-schema": {
diff --git a/package.json b/package.json
index 41160396..61821820 100644
--- a/package.json
+++ b/package.json
@@ -60,7 +60,7 @@
     "temp": "^0.8.3",
     "tsc-then": "^1.0.1",
     "tslint": "^4.1.1",
-    "typescript": "^2.6.1",
+    "typescript": "^2.8.0-dev.20180125",
     "typescript-json-schema": "^0.19.0"
   },
   "dependencies": {
diff --git a/src/analysis-format/generate-analysis.ts b/src/analysis-format/generate-analysis.ts
index ad5ff303..21cba565 100644
--- a/src/analysis-format/generate-analysis.ts
+++ b/src/analysis-format/generate-analysis.ts
@@ -306,7 +306,7 @@ function serializeElementMixin(
 function serializePolymerBehaviorAsElementMixin(
     behavior: ResolvedPolymerBehavior, urlResolver: UrlResolver): ElementMixin {
   const metadata = serializeElementLike(behavior, urlResolver) as ElementMixin;
-  metadata.name = behavior.className;
+  metadata.name = behavior.className!;
   metadata.privacy = behavior.privacy;
   if (behavior.mixins.length > 0) {
     metadata.mixins = behavior.mixins.map((m) => m.identifier);
diff --git a/src/core/analysis-context.ts b/src/core/analysis-context.ts
index 2f814dc9..f1103dfa 100644
--- a/src/core/analysis-context.ts
+++ b/src/core/analysis-context.ts
@@ -137,6 +137,7 @@ export class AnalysisContext {
         options.scanners || AnalysisContext.getDefaultScanners(this._lazyEdges);
     this._cache = cache || new AnalysisCache();
     this._generation = generation || 0;
+    this._analysisComplete = Promise.resolve();
   }
 
   /**
@@ -431,12 +432,11 @@ export class AnalysisContext {
       };
       try {
         const parsedDoc = this._parseContents(
-            feature.type,
-            feature.contents,
-            containingDocument.url,
-            {locationOffset, astNode: feature.astNode});
-        // Inline documents inherit the base url of their containers.
-        parsedDoc.baseUrl = containingDocument.document.baseUrl;
+            feature.type, feature.contents, containingDocument.url, {
+              locationOffset,
+              astNode: feature.astNode,
+              baseUrl: containingDocument.document.baseUrl
+            });
         const scannedDoc = await this._scanDocument(
             parsedDoc, feature.attachedComment, containingDocument.document);
 
@@ -494,7 +494,7 @@ export class AnalysisContext {
    */
   private _parseContents(
       type: string, contents: string, url: ResolvedUrl,
-      inlineInfo?: InlineDocInfo<any>): ParsedDocument {
+      inlineInfo?: InlineDocInfo): ParsedDocument {
     const parser = this.parsers.get(type);
     if (parser == null) {
       throw new NoKnownParserError(`No parser for for file type ${type}`);
diff --git a/src/core/utils.ts b/src/core/utils.ts
index 8e28dcf5..029b8561 100644
--- a/src/core/utils.ts
+++ b/src/core/utils.ts
@@ -46,8 +46,8 @@ export function isPathInside(directory: string, filePath: string): boolean {
 
 export class Deferred<T> {
   promise: Promise<T>;
-  resolve: (result: T) => void;
-  reject: (error: Error) => void;
+  resolve!: (result: T) => void;
+  reject!: (error: Error) => void;
   resolved = false;
   rejected = false;
   error: any;
diff --git a/src/css/css-document.ts b/src/css/css-document.ts
index 4523e806..68aef6f0 100644
--- a/src/css/css-document.ts
+++ b/src/css/css-document.ts
@@ -15,18 +15,14 @@
 import * as shady from 'shady-css-parser';
 
 import {SourceRange} from '../model/model';
-import {Options, ParsedDocument, StringifyOptions} from '../parser/document';
+import {ParsedDocument, StringifyOptions} from '../parser/document';
 
 import cssbeautify = require('cssbeautify');
 
 export interface Visitor { visit(node: shady.Node): void; }
 
 export class ParsedCssDocument extends ParsedDocument<shady.Node, Visitor> {
-  type = 'css';
-
-  constructor(from: Options<shady.Node>) {
-    super(from);
-  }
+  readonly type = 'css';
 
   visit(visitors: Visitor[]) {
     for (const node of this) {
diff --git a/src/css/css-parser.ts b/src/css/css-parser.ts
index af86919d..9c909e03 100644
--- a/src/css/css-parser.ts
+++ b/src/css/css-parser.ts
@@ -30,12 +30,13 @@ export class CssParser implements Parser<ParsedCssDocument> {
 
   parse(
       contents: string, url: ResolvedUrl, _urlResolver: UrlResolver,
-      inlineInfo?: InlineDocInfo<any>): ParsedCssDocument {
+      inlineInfo?: InlineDocInfo): ParsedCssDocument {
     const ast = this._parser.parse(contents);
     const isInline = !!inlineInfo;
     inlineInfo = inlineInfo || {};
     return new ParsedCssDocument({
       url,
+      baseUrl: inlineInfo.baseUrl,
       contents,
       ast,
       locationOffset: inlineInfo.locationOffset,
diff --git a/src/html/html-document.ts b/src/html/html-document.ts
index d5bef4d7..c322bf4a 100644
--- a/src/html/html-document.ts
+++ b/src/html/html-document.ts
@@ -18,7 +18,7 @@ import * as parse5 from 'parse5';
 import {ASTNode} from 'parse5';
 
 import {SourceRange} from '../model/model';
-import {Options, ParsedDocument, StringifyOptions} from '../parser/document';
+import {ParsedDocument, StringifyOptions} from '../parser/document';
 
 /**
  * The ASTs of the HTML elements needed to represent Polymer elements.
@@ -29,10 +29,6 @@ export interface HtmlVisitor { (node: ASTNode): void; }
 export class ParsedHtmlDocument extends ParsedDocument<ASTNode, HtmlVisitor> {
   type = 'html';
 
-  constructor(from: Options<ASTNode>) {
-    super(from);
-  }
-
   visit(visitors: HtmlVisitor[]) {
     dom5.nodeWalk(this.ast, (node) => {
       visitors.forEach((visitor) => visitor(node));
diff --git a/src/html/html-parser.ts b/src/html/html-parser.ts
index c3b00aa9..c49372e8 100644
--- a/src/html/html-parser.ts
+++ b/src/html/html-parser.ts
@@ -31,7 +31,7 @@ export class HtmlParser implements Parser<ParsedHtmlDocument> {
    */
   parse(
       contents: string, url: ResolvedUrl, urlResolver: UrlResolver,
-      inlineInfo?: InlineDocInfo<any>): ParsedHtmlDocument {
+      inlineInfo?: InlineDocInfo): ParsedHtmlDocument {
     const ast = parseHtml(contents, {locationInfo: true});
 
     // There should be at most one <base> tag and it must be inside <head> tag.
@@ -42,16 +42,20 @@ export class HtmlParser implements Parser<ParsedHtmlDocument> {
             p.hasTagName('base'),
             p.hasAttr('href')));
 
-    let baseUrl;
+    const isInline = !!inlineInfo;
+    inlineInfo = inlineInfo || {};
+
+    let baseUrl: ResolvedUrl =
+        inlineInfo.baseUrl !== undefined ? inlineInfo.baseUrl : url;
     if (baseTag) {
-      const baseHref = getAttribute(baseTag, 'href')! as FileRelativeUrl;
-      baseUrl = urlResolver.resolve(url, baseHref, undefined);
-    } else {
-      baseUrl = url;
+      const baseTagHref = getAttribute(baseTag, 'href')! as FileRelativeUrl;
+      const resolvedBaseTagHref =
+          urlResolver.resolve(url, baseTagHref, undefined);
+      if (resolvedBaseTagHref !== undefined) {
+        baseUrl = resolvedBaseTagHref;
+      }
     }
 
-    const isInline = !!inlineInfo;
-    inlineInfo = inlineInfo || {};
     return new ParsedHtmlDocument({
       url,
       baseUrl,
diff --git a/src/html/html-script-tag.ts b/src/html/html-script-tag.ts
index aa3001eb..6a2f0d4a 100644
--- a/src/html/html-script-tag.ts
+++ b/src/html/html-script-tag.ts
@@ -21,14 +21,14 @@ import {FileRelativeUrl} from '../model/url';
  * represents a script tag with a `src` attribute as an import, so that the
  * analyzer loads and parses the referenced document.
  */
-export class ScriptTagImport extends Import { type: 'html-script'; }
+export class ScriptTagImport extends Import { readonly type = 'html-script'; }
 
 /**
  * A synthetic import that provides the document containing the script tag to
  * the javascript document defined/referenced by the script tag.
  */
 export class ScriptTagBackReferenceImport extends Import {
-  type: 'html-script-back-reference';
+  readonly type = 'html-script-back-reference';
 }
 
 export class ScannedScriptTagImport extends ScannedImport {
diff --git a/src/javascript/javascript-document.ts b/src/javascript/javascript-document.ts
index 9ff7fdef..aae371af 100644
--- a/src/javascript/javascript-document.ts
+++ b/src/javascript/javascript-document.ts
@@ -43,9 +43,9 @@ export interface Options extends ParsedDocumentOptions<Program> {
 }
 
 export class JavaScriptDocument extends ParsedDocument<Node, Visitor> {
-  type = 'js';
+  readonly type = 'js';
   private visitorSkips = new Map<Visitor, SkipRecord>();
-  ast: Program;
+  ast!: Program;  // assigned in super, this type is just a refinement.
 
   /**
    * How the js document was parsed. If 'module' then the source code is
diff --git a/src/javascript/javascript-parser.ts b/src/javascript/javascript-parser.ts
index 049df39c..9a52236a 100644
--- a/src/javascript/javascript-parser.ts
+++ b/src/javascript/javascript-parser.ts
@@ -44,11 +44,11 @@ const baseParseOptions: babylon.BabylonOptions = {
 (baseParseOptions as any)['ranges'] = true;
 
 export class JavaScriptParser implements Parser<JavaScriptDocument> {
-  sourceType: SourceType;
+  readonly sourceType?: SourceType;
 
   parse(
       contents: string, url: ResolvedUrl, _urlResolver: UrlResolver,
-      inlineInfo?: InlineDocInfo<any>): JavaScriptDocument {
+      inlineInfo?: InlineDocInfo): JavaScriptDocument {
     const isInline = !!inlineInfo;
     inlineInfo = inlineInfo || {};
     const result = parseJs(
@@ -58,6 +58,7 @@ export class JavaScriptParser implements Parser<JavaScriptDocument> {
       const minimalDocument = new JavaScriptDocument({
         url,
         contents,
+        baseUrl: inlineInfo.baseUrl,
         ast: null as any,
         locationOffset: inlineInfo.locationOffset,
         astNode: inlineInfo.astNode,
@@ -71,6 +72,7 @@ export class JavaScriptParser implements Parser<JavaScriptDocument> {
     return new JavaScriptDocument({
       url,
       contents,
+      baseUrl: inlineInfo.baseUrl,
       ast: result.program,
       locationOffset: inlineInfo.locationOffset,
       astNode: inlineInfo.astNode,
@@ -81,11 +83,11 @@ export class JavaScriptParser implements Parser<JavaScriptDocument> {
 }
 
 export class JavaScriptModuleParser extends JavaScriptParser {
-  sourceType: SourceType = 'module';
+  readonly sourceType: SourceType = 'module';
 }
 
 export class JavaScriptScriptParser extends JavaScriptParser {
-  sourceType: SourceType = 'script';
+  readonly sourceType: SourceType = 'script';
 }
 
 export type ParseResult = {
diff --git a/src/json/json-document.ts b/src/json/json-document.ts
index a6a64d9b..1a10fc02 100644
--- a/src/json/json-document.ts
+++ b/src/json/json-document.ts
@@ -13,7 +13,7 @@
  */
 
 import {SourceRange} from '../model/model';
-import {Options, ParsedDocument} from '../parser/document';
+import {ParsedDocument} from '../parser/document';
 
 export type Json = JsonObject|JsonArray|number|string|boolean|null;
 export interface JsonObject { [key: string]: Json; }
@@ -22,11 +22,7 @@ export interface JsonArray extends Array<Json> {}
 export interface Visitor { visit(node: Json): void; }
 
 export class ParsedJsonDocument extends ParsedDocument<Json, Visitor> {
-  type = 'json';
-
-  constructor(from: Options<Json>) {
-    super(from);
-  }
+  readonly type = 'json';
 
   visit(visitors: Visitor[]) {
     this._visit(this.ast, visitors);
diff --git a/src/json/json-parser.ts b/src/json/json-parser.ts
index 5cdc3b0c..4c95af84 100644
--- a/src/json/json-parser.ts
+++ b/src/json/json-parser.ts
@@ -22,11 +22,12 @@ import {ParsedJsonDocument} from './json-document';
 export class JsonParser implements Parser<ParsedJsonDocument> {
   parse(
       contents: string, url: ResolvedUrl, _urlResolver: UrlResolver,
-      inlineDocInfo: InlineDocInfo<any>): ParsedJsonDocument {
+      inlineDocInfo: InlineDocInfo): ParsedJsonDocument {
     const isInline = !!inlineDocInfo;
     inlineDocInfo = inlineDocInfo || {};
     return new ParsedJsonDocument({
       url,
+      baseUrl: inlineDocInfo.baseUrl,
       contents,
       ast: JSON.parse(contents),
       locationOffset: inlineDocInfo.locationOffset,
diff --git a/src/model/document.ts b/src/model/document.ts
index ce0d4f6b..7758fa95 100644
--- a/src/model/document.ts
+++ b/src/model/document.ts
@@ -43,7 +43,7 @@ export class ScannedDocument {
   get sourceRange() {
     return this.document.sourceRange;
   }
-  get astNode(): AstNodeWithLanguage|null {
+  get astNode(): AstNodeWithLanguage|undefined {
     return this.document.astNode;
   }
 
@@ -157,7 +157,7 @@ export class Document<ParsedType extends ParsedDocument = ParsedDocument>
     return this._scannedDocument.sourceRange;
   }
 
-  get astNode(): AstNodeWithLanguage|null {
+  get astNode(): AstNodeWithLanguage|undefined {
     return this._scannedDocument.astNode;
   }
 
diff --git a/src/model/element-base.ts b/src/model/element-base.ts
index 4bd4992c..d1ef4370 100644
--- a/src/model/element-base.ts
+++ b/src/model/element-base.ts
@@ -40,14 +40,14 @@ export abstract class ScannedElementBase implements Resolvable {
   demos: Demo[] = [];
   events: Map<string, ScannedEvent> = new Map();
   sourceRange: SourceRange|undefined;
-  staticMethods: Map<string, ScannedMethod>;
-  methods: Map<string, ScannedMethod>;
-  astNode: babel.Node|null;
+  staticMethods: Map<string, ScannedMethod> = new Map();
+  methods: Map<string, ScannedMethod> = new Map();
+  astNode: babel.Node|null = null;
   warnings: Warning[] = [];
   jsdoc?: jsdoc.Annotation;
   'slots': Slot[] = [];
   mixins: ScannedReference[] = [];
-  privacy: Privacy;
+  privacy!: Privacy;
   abstract: boolean = false;
   superClass?: ScannedReference = undefined;
 
@@ -145,8 +145,8 @@ export abstract class ElementBase extends Class implements Feature {
     // Initialization of these attributes is kinda awkward, as they're part
     // of the inheritance system. See `inheritFrom` below which *may* be
     // called by our superclass, but may not be.
-    this.attributes = this.attributes || new Map();
-    this.events = this.events || new Map();
+    this.attributes = (this as any).attributes || new Map();
+    this.events = (this as any).events || new Map();
 
     if (attributes !== undefined) {
       this._overwriteInherited(this.attributes, attributes, undefined, true);
diff --git a/src/model/element-mixin.ts b/src/model/element-mixin.ts
index effcc19a..14f4df43 100644
--- a/src/model/element-mixin.ts
+++ b/src/model/element-mixin.ts
@@ -43,5 +43,6 @@ export class ElementMixin extends ElementBase implements Feature {
   constructor(init: ElementMixinInit, document: Document) {
     super(init, document);
     this.kinds.add('element-mixin');
+    this.name = init.name;
   }
 }
diff --git a/src/model/element.ts b/src/model/element.ts
index fe9e11f4..34644f7c 100644
--- a/src/model/element.ts
+++ b/src/model/element.ts
@@ -14,7 +14,7 @@
 
 import {Document} from './document';
 import {ElementBase, ElementBaseInit, ScannedElementBase} from './element-base';
-import {Feature, Privacy} from './feature';
+import {Feature} from './feature';
 import {ScannedReference} from './reference';
 
 export {Visitor} from '../javascript/estree-visitor';
@@ -26,7 +26,6 @@ export class ScannedElement extends ScannedElementBase {
     return this.className;
   }
   superClass?: ScannedReference;
-  privacy: Privacy;
 
   /**
    * For customized built-in elements, the tagname of the superClass.
diff --git a/src/model/inline-document.ts b/src/model/inline-document.ts
index 1f40e2eb..280c3663 100644
--- a/src/model/inline-document.ts
+++ b/src/model/inline-document.ts
@@ -26,11 +26,13 @@ import {ScannedFeature} from './feature';
 import {unsafeAsMutable} from './immutable';
 import {Resolvable} from './resolvable';
 import {LocationOffset, SourceRange} from './source-range';
+import {ResolvedUrl} from './url';
 import {Warning} from './warning';
 
-export interface InlineDocInfo<AstNode> {
-  astNode?: AstNode;
+export interface InlineDocInfo {
+  astNode?: AstNodeWithLanguage;
   locationOffset?: LocationOffset;
+  baseUrl?: ResolvedUrl;
 }
 
 export type AstNodeWithLanguage = {
diff --git a/src/model/reference.ts b/src/model/reference.ts
index 810ed9fa..7d6b4bda 100644
--- a/src/model/reference.ts
+++ b/src/model/reference.ts
@@ -32,6 +32,7 @@ export class ScannedReference extends ScannedFeature implements Resolvable {
       identifier: string, sourceRange: SourceRange, astNode?: any,
       description?: string, jsdoc?: Annotation, warnings?: Warning[]) {
     super(sourceRange, astNode, description, jsdoc, warnings);
+    this.sourceRange = sourceRange;
     this.identifier = identifier;
   }
 
diff --git a/src/parser/document.ts b/src/parser/document.ts
index 52f4f3f2..bf78a6ce 100644
--- a/src/parser/document.ts
+++ b/src/parser/document.ts
@@ -34,7 +34,7 @@ export abstract class ParsedDocument<AstNode = any, Visitor = any> {
    * If not null, this is an inline document, and astNode is the AST Node of
    * this document inside of the parent. (e.g. the <style> or <script> tag)
    */
-  readonly astNode: AstNodeWithLanguage|null;
+  readonly astNode: AstNodeWithLanguage|undefined;
 
   sourceRange: SourceRange;
 
@@ -156,11 +156,11 @@ export abstract class ParsedDocument<AstNode = any, Visitor = any> {
 
 export interface Options<A> {
   url: ResolvedUrl;
-  baseUrl?: ResolvedUrl;
+  baseUrl: ResolvedUrl|undefined;
   contents: string;
   ast: A;
   locationOffset: LocationOffset|undefined;
-  astNode: AstNodeWithLanguage|null;
+  astNode: AstNodeWithLanguage|undefined;
   isInline: boolean;
 }
 
@@ -186,7 +186,7 @@ export class UnparsableParsedDocument extends ParsedDocument {
       ast: null,
       url,
       baseUrl: url,
-      astNode: null,
+      astNode: undefined,
       contents: contents,
       isInline: false,
       locationOffset: undefined
diff --git a/src/parser/parser.ts b/src/parser/parser.ts
index 1100af47..46a6aa2d 100644
--- a/src/parser/parser.ts
+++ b/src/parser/parser.ts
@@ -21,5 +21,5 @@ import {ParsedDocument} from './document';
 export interface Parser<D extends ParsedDocument<any, any>> {
   parse(
       contents: string, url: ResolvedUrl, urlResolver: UrlResolver,
-      inlineDocInfo?: InlineDocInfo<any>): D;
+      inlineDocInfo?: InlineDocInfo): D;
 }
diff --git a/src/polymer/behavior-scanner.ts b/src/polymer/behavior-scanner.ts
index 6227dfc2..c457c05c 100644
--- a/src/polymer/behavior-scanner.ts
+++ b/src/polymer/behavior-scanner.ts
@@ -202,7 +202,8 @@ class BehaviorVisitor implements Visitor {
   mergeBehavior(newBehavior: ScannedBehavior): ScannedBehavior {
     const isBehaviorImpl = (b: ScannedBehaviorAssignment) => {
       // filter out BehaviorImpl
-      return b.name.indexOf(newBehavior.className) === -1;
+      return newBehavior.className === undefined ||
+          b.name.indexOf(newBehavior.className) === -1;
     };
     for (const behavior of this.behaviors) {
       if (newBehavior.className !== behavior.className) {
diff --git a/src/polymer/behavior.ts b/src/polymer/behavior.ts
index dd022776..6a00fc0e 100644
--- a/src/polymer/behavior.ts
+++ b/src/polymer/behavior.ts
@@ -40,7 +40,7 @@ export interface Options extends ElementOptions {}
  */
 export class ScannedBehavior extends ScannedPolymerElement {
   tagName: undefined;
-  className: string;
+  className?: string;
 
   resolve(document: Document) {
     return new Behavior(this, document);
@@ -55,9 +55,6 @@ declare module '../model/queryable' {
 
 export class Behavior extends PolymerElement {
   readonly tagName: undefined = undefined;
-  readonly name: string;
-  readonly className: string;
-
   constructor(scannedBehavior: ScannedBehavior, document: Document) {
     super(scannedBehavior, document);
     this.kinds.delete('element');
diff --git a/src/polymer/polymer-element-mixin.ts b/src/polymer/polymer-element-mixin.ts
index 87f11b52..c29647e7 100644
--- a/src/polymer/polymer-element-mixin.ts
+++ b/src/polymer/polymer-element-mixin.ts
@@ -86,10 +86,11 @@ declare module '../model/queryable' {
 }
 export class PolymerElementMixin extends ElementMixin implements
     PolymerExtension {
-  readonly properties: Map<string, PolymerProperty>;
+  // This property is assigned in the super class.
+  readonly properties!: Map<string, PolymerProperty>;
 
   readonly observers: Observer[];
-  readonly listeners: {event: string, handler: string}[];
+  readonly listeners: {event: string, handler: string}[] = [];
   readonly behaviorAssignments: ScannedBehaviorAssignment[] = [];
   readonly localIds: LocalId[] = [];
   readonly pseudo: boolean;
diff --git a/src/polymer/polymer-element.ts b/src/polymer/polymer-element.ts
index 5f982a85..d0c8e70c 100644
--- a/src/polymer/polymer-element.ts
+++ b/src/polymer/polymer-element.ts
@@ -305,7 +305,8 @@ declare module '../model/queryable' {
 }
 
 export class PolymerElement extends Element implements PolymerExtension {
-  readonly properties: Map<string, PolymerProperty>;
+  // This property is assigned in the super class. We just refine its type here.
+  readonly properties!: Map<string, PolymerProperty>;
   readonly observers: ImmutableArray<Observer> = [];
   readonly listeners: ImmutableArray<{event: string, handler: string}> = [];
   readonly behaviorAssignments: ImmutableArray<ScannedBehaviorAssignment> = [];
@@ -314,6 +315,8 @@ export class PolymerElement extends Element implements PolymerExtension {
 
   constructor(scannedElement: ScannedPolymerElement, document: Document) {
     super(scannedElement, document);
+
+
     this.kinds.add('polymer-element');
 
     this.observers = Array.from(scannedElement.observers);
diff --git a/src/test/parser/document_test.ts b/src/test/parser/document_test.ts
index 469d53c2..b4abcf5f 100644
--- a/src/test/parser/document_test.ts
+++ b/src/test/parser/document_test.ts
@@ -15,10 +15,10 @@ import {assert} from 'chai';
 
 import {SourceRange} from '../../model/model';
 import {ParsedDocument, StringifyOptions} from '../../parser/document';
-import { resolvedUrl } from '../test-utils';
+import {resolvedUrl} from '../test-utils';
 
 class TestDocument extends ParsedDocument<null, null> {
-  type: string;
+  readonly type = 'test-document';
   visit(_visitors: null[]): void {
     throw new Error('Method not implemented.');
   }
@@ -32,7 +32,7 @@ class TestDocument extends ParsedDocument<null, null> {
   constructor(contents: string) {
     super({
       ast: null,
-      astNode: null,
+      astNode: undefined,
       baseUrl: resolvedUrl`test-document`,
       contents,
       isInline: false,
diff --git a/src/test/polymer/behavior-scanner_test.ts b/src/test/polymer/behavior-scanner_test.ts
index 0f7f3b1e..ded206f6 100644
--- a/src/test/polymer/behavior-scanner_test.ts
+++ b/src/test/polymer/behavior-scanner_test.ts
@@ -33,6 +33,9 @@ suite('BehaviorScanner', () => {
     behaviorsList =
         <ScannedBehavior[]>features.filter((e) => e instanceof ScannedBehavior);
     for (const behavior of behaviorsList) {
+      if (behavior.className === undefined) {
+        throw new Error(`Could not determine className of behavior.`);
+      }
       behaviors.set(behavior.className, behavior);
     }
   });
diff --git a/src/test/typescript/typescript-analyzer_test.ts b/src/test/typescript/typescript-analyzer_test.ts
index 55ce27b9..d2bd0e20 100644
--- a/src/test/typescript/typescript-analyzer_test.ts
+++ b/src/test/typescript/typescript-analyzer_test.ts
@@ -59,7 +59,7 @@ suite('TypeScriptParser', () => {
 
       // Get the HTMLElement type from the DOM module
       let htmlElement: ts.Type;
-      const domSource = program.getSourceFile('/$lib/DOM.d.ts');
+      const domSource = program.getSourceFile('/$lib/DOM.d.ts')!;
       ts.forEachChild(domSource, (node) => {
         if (node.kind === ts.SyntaxKind.InterfaceDeclaration) {
           const innerface = node as ts.InterfaceDeclaration;
@@ -70,7 +70,7 @@ suite('TypeScriptParser', () => {
       });
 
       // Get class A and assert that it extends HTMLElement
-      const sourceFile = program.getSourceFile(fileName);
+      const sourceFile = program.getSourceFile(fileName)!;
       ts.forEachChild(sourceFile, (node) => {
         if (node.kind === ts.SyntaxKind.ClassDeclaration) {
           const class_ = node as ts.ClassDeclaration;
diff --git a/src/test/url-loader/multi-url-loader_test.ts b/src/test/url-loader/multi-url-loader_test.ts
index ffcd83a2..69e5d3b8 100644
--- a/src/test/url-loader/multi-url-loader_test.ts
+++ b/src/test/url-loader/multi-url-loader_test.ts
@@ -19,15 +19,9 @@ import {UrlLoader} from '../../url-loader/url-loader';
 import {invertPromise, resolvedUrl} from '../test-utils';
 
 class MockLoader implements UrlLoader {
-  canLoadCount: number;
-  loadCount: number;
+  canLoadCount = 0;
+  loadCount = 0;
   constructor(private _load: string|null) {
-    this.resetCounts();
-  }
-
-  resetCounts() {
-    this.canLoadCount = 0;
-    this.loadCount = 0;
   }
 
   canLoad(_url: string): boolean {
diff --git a/src/test/url-loader/prefixed-url-loader_test.ts b/src/test/url-loader/prefixed-url-loader_test.ts
index 863e31ce..0b55c1ac 100644
--- a/src/test/url-loader/prefixed-url-loader_test.ts
+++ b/src/test/url-loader/prefixed-url-loader_test.ts
@@ -19,16 +19,11 @@ import {UrlLoader} from '../../url-loader/url-loader';
 import {invertPromise, resolvedUrl} from '../test-utils';
 
 class MockLoader implements UrlLoader {
-  canLoadUrls: string[];
-  loadUrls: string[];
+  canLoadUrls: string[] = [];
+  loadUrls: string[] = [];
   constructor(private _load: string|null) {
-    this.reset();
   }
 
-  reset() {
-    this.canLoadUrls = [];
-    this.loadUrls = [];
-  }
 
   canLoad(url: string): boolean {
     this.canLoadUrls.push(url);
diff --git a/src/typescript/typescript-document.ts b/src/typescript/typescript-document.ts
index 2b813b84..2ec826cc 100644
--- a/src/typescript/typescript-document.ts
+++ b/src/typescript/typescript-document.ts
@@ -16,7 +16,7 @@ import * as ts from 'typescript';
 import {Node} from 'typescript';
 
 import {SourceRange} from '../model/model';
-import {Options, ParsedDocument, StringifyOptions} from '../parser/document';
+import {ParsedDocument, StringifyOptions} from '../parser/document';
 
 import {Visitor} from './typescript-visitor';
 
@@ -25,13 +25,7 @@ export {Options} from '../parser/document';
 export {Visitor} from './typescript-visitor';
 
 export class ParsedTypeScriptDocument extends ParsedDocument<Node, Visitor> {
-  type = 'typescript';
-
-  constructor(from: Options<Node>) {
-    // This constructor is neccessary because the default constructor that
-    // TypeScript generates uses spread syntax which in unsupported by node 4.
-    super(from);
-  }
+  readonly type = 'typescript';
 
   visit(visitors: Visitor[]) {
     const sourceFile = this.ast;
diff --git a/src/typescript/typescript-preparser.ts b/src/typescript/typescript-preparser.ts
index 7de2f772..e7c3554a 100644
--- a/src/typescript/typescript-preparser.ts
+++ b/src/typescript/typescript-preparser.ts
@@ -37,7 +37,7 @@ import {ParsedTypeScriptDocument} from './typescript-document';
 export class TypeScriptPreparser implements Parser<ParsedTypeScriptDocument> {
   parse(
       contents: string, url: ResolvedUrl, _urlResolver: UrlResolver,
-      inlineInfo?: InlineDocInfo<any>): ParsedTypeScriptDocument {
+      inlineInfo?: InlineDocInfo): ParsedTypeScriptDocument {
     const isInline = !!inlineInfo;
     inlineInfo = inlineInfo || {};
     const sourceFile =
@@ -52,6 +52,7 @@ export class TypeScriptPreparser implements Parser<ParsedTypeScriptDocument> {
     const result = new ParsedTypeScriptDocument({
       url,
       contents,
+      baseUrl: inlineInfo.baseUrl,
       ast: sourceFile,
       locationOffset: inlineInfo.locationOffset,
       astNode: inlineInfo.astNode,
diff --git a/tsconfig.json b/tsconfig.json
index 3b3f78a9..d237e6f1 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -11,6 +11,7 @@
     "strictNullChecks": true,
     "removeComments": false,
     "preserveConstEnums": true,
+    "strictPropertyInitialization": true,
     "suppressImplicitAnyIndexErrors": false,
     "lib": [
       "es2017"

From e58638f85188517310af868d7665a063262a2d76 Mon Sep 17 00:00:00 2001
From: Peter Burns <rictic@google.com>
Date: Wed, 31 Jan 2018 11:06:40 -0800
Subject: [PATCH 2/3] Remove semicolon that crashes tsc.
 https://github.com/Microsoft/TypeScript/issues/21491

---
 src/parser/document.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/parser/document.ts b/src/parser/document.ts
index bf78a6ce..8ccc4b5a 100644
--- a/src/parser/document.ts
+++ b/src/parser/document.ts
@@ -75,7 +75,7 @@ export abstract class ParsedDocument<AstNode = any, Visitor = any> {
   sourceRangeForNode(node: AstNode): SourceRange|undefined {
     const baseSource = this._sourceRangeForNode(node);
     return this.relativeToAbsoluteSourceRange(baseSource);
-  };
+  }
 
   protected abstract _sourceRangeForNode(node: AstNode): SourceRange|undefined;
 

From 4743d094e085cf87abe9245c338abac941acb6e4 Mon Sep 17 00:00:00 2001
From: Peter Burns <rictic@google.com>
Date: Wed, 31 Jan 2018 11:12:12 -0800
Subject: [PATCH 3/3] Use tsc @ 2.71 now that it is out.

---
 package-lock.json | 6 +++---
 package.json      | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 092d179b..47757082 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4686,9 +4686,9 @@
       "dev": true
     },
     "typescript": {
-      "version": "2.8.0-dev.20180125",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-2.8.0-dev.20180125.tgz",
-      "integrity": "sha512-D5kzJ/iG752X4Nko+Ga3B9Iu/96qj2MIiqAhDIVuzMIdVp1Hi7MHrDqzaU/FjLCiiq2OuhBdIRqkk3Vr5a57HA==",
+      "version": "2.7.1",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-2.7.1.tgz",
+      "integrity": "sha512-bqB1yS6o9TNA9ZC/MJxM0FZzPnZdtHj0xWK/IZ5khzVqdpGul/R/EIiHRgFXlwTD7PSIaYVnGKq1QgMCu2mnqw==",
       "dev": true
     },
     "typescript-json-schema": {
diff --git a/package.json b/package.json
index 61821820..02249860 100644
--- a/package.json
+++ b/package.json
@@ -60,7 +60,7 @@
     "temp": "^0.8.3",
     "tsc-then": "^1.0.1",
     "tslint": "^4.1.1",
-    "typescript": "^2.8.0-dev.20180125",
+    "typescript": "^2.7.1",
     "typescript-json-schema": "^0.19.0"
   },
   "dependencies": {