diff --git a/packages/language-service/src/typescript_symbols.ts b/packages/language-service/src/typescript_symbols.ts
index 6635ee5a18..73c7dfe28e 100644
--- a/packages/language-service/src/typescript_symbols.ts
+++ b/packages/language-service/src/typescript_symbols.ts
@@ -280,7 +280,20 @@ class TypeWrapper implements Symbol {
     return selectSignature(this.tsType, this.context, types);
   }
 
-  indexed(argument: Symbol): Symbol|undefined { return undefined; }
+  indexed(argument: Symbol): Symbol|undefined {
+    const type = argument instanceof TypeWrapper ? argument : argument.type;
+    if (!(type instanceof TypeWrapper)) return;
+
+    const typeKind = typeKindOf(type.tsType);
+    switch (typeKind) {
+      case BuiltinType.Number:
+        const nType = this.tsType.getNumberIndexType();
+        return nType && new TypeWrapper(nType, this.context);
+      case BuiltinType.String:
+        const sType = this.tsType.getStringIndexType();
+        return sType && new TypeWrapper(sType, this.context);
+    }
+  }
 }
 
 class SymbolWrapper implements Symbol {
diff --git a/packages/language-service/test/completions_spec.ts b/packages/language-service/test/completions_spec.ts
index 94ce983126..5dc83ef417 100644
--- a/packages/language-service/test/completions_spec.ts
+++ b/packages/language-service/test/completions_spec.ts
@@ -117,6 +117,20 @@ describe('completions', () => {
     expectContain(completions, CompletionKind.PROPERTY, ['id', 'name']);
   });
 
+  it('should be able to get property completions for members in an array', () => {
+    mockHost.override(TEST_TEMPLATE, `{{ heroes[0].~{heroes-number-index}}}`);
+    const marker = mockHost.getLocationMarkerFor(TEST_TEMPLATE, 'heroes-number-index');
+    const completions = ngLS.getCompletionsAt(TEST_TEMPLATE, marker.start);
+    expectContain(completions, CompletionKind.PROPERTY, ['id', 'name']);
+  });
+
+  it('should be able to get property completions for members in an indexed type', () => {
+    mockHost.override(TEST_TEMPLATE, `{{ heroesByName['Jacky'].~{heroes-string-index}}}`);
+    const marker = mockHost.getLocationMarkerFor(TEST_TEMPLATE, 'heroes-string-index');
+    const completions = ngLS.getCompletionsAt(TEST_TEMPLATE, marker.start);
+    expectContain(completions, CompletionKind.PROPERTY, ['id', 'name']);
+  });
+
   it('should be able to return attribute names with an incompete attribute', () => {
     const marker = mockHost.getLocationMarkerFor(PARSING_CASES, 'no-value-attribute');
     const completions = ngLS.getCompletionsAt(PARSING_CASES, marker.start);
diff --git a/packages/language-service/test/diagnostics_spec.ts b/packages/language-service/test/diagnostics_spec.ts
index edd0ec103a..ad0127d3ce 100644
--- a/packages/language-service/test/diagnostics_spec.ts
+++ b/packages/language-service/test/diagnostics_spec.ts
@@ -119,6 +119,15 @@ describe('diagnostics', () => {
     expect(diagnostics).toEqual([]);
   });
 
+  it('should produce diagnostics for invalid index type property access', () => {
+    mockHost.override(TEST_TEMPLATE, `
+        {{heroes[0].badProperty}}`);
+    const diags = ngLS.getDiagnostics(TEST_TEMPLATE);
+    expect(diags.length).toBe(1);
+    expect(diags[0].messageText)
+        .toBe(`Identifier 'badProperty' is not defined. 'Hero' does not contain such a member`);
+  });
+
   describe('in expression-cases.ts', () => {
     it('should report access to an unknown field', () => {
       const diags = ngLS.getDiagnostics(EXPRESSION_CASES).map(d => d.messageText);
diff --git a/packages/language-service/test/project/app/parsing-cases.ts b/packages/language-service/test/project/app/parsing-cases.ts
index 1fe3aa7ab6..e9bd88f136 100644
--- a/packages/language-service/test/project/app/parsing-cases.ts
+++ b/packages/language-service/test/project/app/parsing-cases.ts
@@ -190,6 +190,7 @@ export class TemplateReference {
   hero: Hero = {id: 1, name: 'Windstorm'};
   heroes: Hero[] = [this.hero];
   league: Hero[][] = [this.heroes];
+  heroesByName: {[name: string]: Hero} = {};
   anyValue: any;
   myClick(event: any) {}
 }