diff --git a/AUTHORS.md b/AUTHORS.md
index 486a15bf47..0501514d75 100644
--- a/AUTHORS.md
+++ b/AUTHORS.md
@@ -2,9 +2,11 @@ TypeScript is authored by:
 
 * Adam Freidin
 * Ahmad Farid 
+* Akshar Patel
 * Anders Hejlsberg
 * Arnav Singh
 * Arthur Ozga
+* Asad Saeeduddin
 * Basarat Ali Syed 
 * Ben Duffield
 * Bill Ticehurst 
@@ -15,30 +17,39 @@ TypeScript is authored by:
 * Colby Russell 
 * Colin Snover
 * Cyrus Najmabadi
+* Dan Corder
 * Dan Quirk 
 * Daniel Rosenwasser
+* @dashaus
 * David Li 
 * Denis Nedelyaev
 * Dick van den Brink
 * Dirk Bäumer
+* Dirk Holtwick
 * Eyas Sharaiha
+* @falsandtru
 * Frank Wallis 
 * Gabriel Isenberg
 * Gilad Peleg 
 * Graeme Wicksted
 * Guillaume Salles 
+* Guy Bedford
 * Harald Niesche
+* Iain Monro
 * Ingvar Stepanyan
 * Ivo Gabe de Wolff 
 * James Whitney 
 * Jason Freeman
+* Jason Killian
 * Jason Ramsay 
 * Jed Mao
+* Jeffrey Morlan
 * Johannes Rieken 
 * John Vilk
 * Jonathan Bond-Caron
 * Jonathan Park
 * Jonathan Turner
+* Jonathon Smith
 * Josh Kalderimis
 * Julian Williams
 * Kagami Sascha Rosylight
@@ -46,21 +57,27 @@ TypeScript is authored by:
 * Ken Howard
 * Kenji Imamula
 * Lorant Pinter 
+* Lucien Greathouse
 * Martin Všetička
 * Masahiro Wakame
+* Mattias Buelens
 * Max Deepfield
 * Micah Zoltu 
 * Mohamed Hegazy 
 * Nathan Shively-Sanders
+* Nathan Yee
 * Oleg Mihailik
 * Oleksandr Chekhovskyi 
 * Paul van Brenk 
+* @pcbro
 * Pedro Maltez 
 * Philip Bulley
 * piloopin
 * @progre
 * Punya Biswal
+* Richard Sentino
 * Ron Buckton 
+* Rowan Wyborn
 * Ryan Cavanaugh 
 * Ryohei Ikegami
 * Sébastien Arod
@@ -71,7 +88,9 @@ TypeScript is authored by:
 * Solal Pirelli
 * Stan Thomas
 * Steve Lucco
+* Thomas Loubiou
 * Tien Hoanhtien
+* Tim Perry
 * Tingan Ho
 * togru
 * Tomas Grubliauskas
@@ -81,5 +100,6 @@ TypeScript is authored by:
 * Wesley Wigham
 * York Yao
 * Yui Tanglertsampan
+* Yuichi Nukiyama
 * Zev Spitz 
 * Zhengbo Li
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 11f550bad5..6adf39377c 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -10442,7 +10442,8 @@ namespace ts {
                     }
                     else {
                         error(func, Diagnostics.No_best_common_type_exists_among_return_expressions);
-                        return unknownType;
+                        // Defer to unioning the return types so we get a) downstream errors earlier and b) better Salsa experience
+                        return getUnionType(types);
                     }
                 }
 
@@ -15379,6 +15380,20 @@ namespace ts {
                 return getSymbolOfNode(entityName.parent);
             }
 
+            if (isInJavaScriptFile(entityName) && entityName.parent.kind === SyntaxKind.PropertyAccessExpression) {
+                const specialPropertyAssignmentKind = getSpecialPropertyAssignmentKind(entityName.parent.parent);
+                switch (specialPropertyAssignmentKind) {
+                    case SpecialPropertyAssignmentKind.ExportsProperty:
+                    case SpecialPropertyAssignmentKind.PrototypeProperty:
+                        return getSymbolOfNode(entityName.parent);
+                    case SpecialPropertyAssignmentKind.ThisProperty:
+                    case SpecialPropertyAssignmentKind.ModuleExports:
+                        return getSymbolOfNode(entityName.parent.parent);
+                    default:
+                        // Fall through if it is not a special property assignment
+                }
+            }
+
             if (entityName.parent.kind === SyntaxKind.ExportAssignment) {
                 return resolveEntityName(<Identifier>entityName,
                     /*all meanings*/ SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace | SymbolFlags.Alias);
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 9a57b4b1a3..ab0b16947f 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -637,18 +637,21 @@ namespace ts {
             }
         }
 
-        function emitClassMemberDeclarationFlags(node: Declaration) {
-            if (node.flags & NodeFlags.Private) {
+        function emitClassMemberDeclarationFlags(flags: NodeFlags) {
+            if (flags & NodeFlags.Private) {
                 write("private ");
             }
-            else if (node.flags & NodeFlags.Protected) {
+            else if (flags & NodeFlags.Protected) {
                 write("protected ");
             }
 
-            if (node.flags & NodeFlags.Static) {
+            if (flags & NodeFlags.Static) {
                 write("static ");
             }
-            if (node.flags & NodeFlags.Abstract) {
+            if (flags & NodeFlags.Readonly) {
+                write("readonly ");
+            }
+            if (flags & NodeFlags.Abstract) {
                 write("abstract ");
             }
         }
@@ -1074,7 +1077,7 @@ namespace ts {
             }
 
             emitJsDocComments(node);
-            emitClassMemberDeclarationFlags(node);
+            emitClassMemberDeclarationFlags(node.flags);
             emitVariableDeclaration(<VariableDeclaration>node);
             write(";");
             writeLine();
@@ -1227,7 +1230,7 @@ namespace ts {
             if (node === accessors.firstAccessor) {
                 emitJsDocComments(accessors.getAccessor);
                 emitJsDocComments(accessors.setAccessor);
-                emitClassMemberDeclarationFlags(node);
+                emitClassMemberDeclarationFlags(node.flags | (accessors.setAccessor ? 0 : NodeFlags.Readonly));
                 writeTextOfNode(currentText, node.name);
                 if (!(node.flags & NodeFlags.Private)) {
                     accessorWithTypeAnnotation = node;
@@ -1314,7 +1317,7 @@ namespace ts {
                     emitModuleElementDeclarationFlags(node);
                 }
                 else if (node.kind === SyntaxKind.MethodDeclaration) {
-                    emitClassMemberDeclarationFlags(node);
+                    emitClassMemberDeclarationFlags(node.flags);
                 }
                 if (node.kind === SyntaxKind.FunctionDeclaration) {
                     write("function ");
@@ -1342,15 +1345,17 @@ namespace ts {
             const prevEnclosingDeclaration = enclosingDeclaration;
             enclosingDeclaration = node;
 
-            // Construct signature or constructor type write new Signature
-            if (node.kind === SyntaxKind.ConstructSignature || node.kind === SyntaxKind.ConstructorType) {
-                write("new ");
-            }
-            emitTypeParameters(node.typeParameters);
             if (node.kind === SyntaxKind.IndexSignature) {
+                // Index signature can have readonly modifier
+                emitClassMemberDeclarationFlags(node.flags);
                 write("[");
             }
             else {
+                // Construct signature or constructor type write new Signature
+                if (node.kind === SyntaxKind.ConstructSignature || node.kind === SyntaxKind.ConstructorType) {
+                    write("new ");
+                }
+                emitTypeParameters(node.typeParameters);
                 write("(");
             }
 
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 0a3cbd89d9..27512ab3dc 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -7123,14 +7123,22 @@ const _super = (function (geti, seti) {
 
                 for (let i = 0; i < externalImports.length; i++) {
                     const text = getExternalModuleNameText(externalImports[i], emitRelativePathAsModuleName);
-                    if (hasProperty(groupIndices, text)) {
+                    if (text === undefined) {
+                        continue;
+                    }
+
+                    // text should be quoted string
+                    // for deduplication purposes in key remove leading and trailing quotes so 'a' and "a" will be considered the same                     
+                    const key = text.substr(1, text.length - 2);
+
+                    if (hasProperty(groupIndices, key)) {
                         // deduplicate/group entries in dependency list by the dependency name
-                        const groupIndex = groupIndices[text];
+                        const groupIndex = groupIndices[key];
                         dependencyGroups[groupIndex].push(externalImports[i]);
                         continue;
                     }
                     else {
-                        groupIndices[text] = dependencyGroups.length;
+                        groupIndices[key] = dependencyGroups.length;
                         dependencyGroups.push([externalImports[i]]);
                     }
 
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index bf88a87d3e..787a022140 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -4017,7 +4017,7 @@ namespace ts {
                 setDecoratorContext(/*val*/ true);
             }
 
-            return finishNode(node);
+            return addJSDocComment(finishNode(node));
         }
 
         function parseOptionalIdentifier() {
@@ -4301,13 +4301,13 @@ namespace ts {
                 const labeledStatement = <LabeledStatement>createNode(SyntaxKind.LabeledStatement, fullStart);
                 labeledStatement.label = <Identifier>expression;
                 labeledStatement.statement = parseStatement();
-                return finishNode(labeledStatement);
+                return addJSDocComment(finishNode(labeledStatement));
             }
             else {
                 const expressionStatement = <ExpressionStatement>createNode(SyntaxKind.ExpressionStatement, fullStart);
                 expressionStatement.expression = expression;
                 parseSemicolon();
-                return finishNode(expressionStatement);
+                return addJSDocComment(finishNode(expressionStatement));
             }
         }
 
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 05dc4be1d0..33ad24d7f5 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -1205,7 +1205,19 @@ namespace ts {
                 node.parent.parent.parent.kind === SyntaxKind.VariableStatement;
 
             const variableStatementNode = isInitializerOfVariableDeclarationInStatement ? node.parent.parent.parent : undefined;
-            return variableStatementNode && variableStatementNode.jsDocComment;
+            if (variableStatementNode) {
+                return variableStatementNode.jsDocComment;
+            }
+
+            // Also recognize when the node is the RHS of an assignment expression
+            const isSourceOfAssignmentExpressionStatement =
+                node.parent && node.parent.parent &&
+                node.parent.kind === SyntaxKind.BinaryExpression &&
+                (node.parent as BinaryExpression).operatorToken.kind === SyntaxKind.EqualsToken &&
+                node.parent.parent.kind === SyntaxKind.ExpressionStatement;
+            if (isSourceOfAssignmentExpressionStatement) {
+                return node.parent.parent.jsDocComment;
+            }
         }
 
         return undefined;
diff --git a/tests/baselines/reference/classdecl.js b/tests/baselines/reference/classdecl.js
index 710c5166d3..a8a440fa17 100644
--- a/tests/baselines/reference/classdecl.js
+++ b/tests/baselines/reference/classdecl.js
@@ -211,12 +211,12 @@ declare class a {
     pgF(): void;
     pv: any;
     d: number;
-    static p2: {
+    static readonly p2: {
         x: number;
         y: number;
     };
     private static d2();
-    private static p3;
+    private static readonly p3;
     private pv3;
     private foo(n);
     private foo(s);
diff --git a/tests/baselines/reference/commentsClassMembers.js b/tests/baselines/reference/commentsClassMembers.js
index fe2dc0a63d..dacbde7a27 100644
--- a/tests/baselines/reference/commentsClassMembers.js
+++ b/tests/baselines/reference/commentsClassMembers.js
@@ -568,8 +568,8 @@ declare var i1_c: typeof c1;
 declare class cProperties {
     private val;
     /** getter only property*/
-    p1: number;
-    nc_p1: number;
+    readonly p1: number;
+    readonly nc_p1: number;
     /**setter only property*/
     p2: number;
     nc_p2: number;
diff --git a/tests/baselines/reference/commentsInheritance.js b/tests/baselines/reference/commentsInheritance.js
index b9d84b2475..42df3cca38 100644
--- a/tests/baselines/reference/commentsInheritance.js
+++ b/tests/baselines/reference/commentsInheritance.js
@@ -316,19 +316,19 @@ declare class c2 {
     /** c2 c2_f1*/
     c2_f1(): void;
     /** c2 c2_prop*/
-    c2_prop: number;
+    readonly c2_prop: number;
     c2_nc_p1: number;
     c2_nc_f1(): void;
-    c2_nc_prop: number;
+    readonly c2_nc_prop: number;
     /** c2 p1*/
     p1: number;
     /** c2 f1*/
     f1(): void;
     /** c2 prop*/
-    prop: number;
+    readonly prop: number;
     nc_p1: number;
     nc_f1(): void;
-    nc_prop: number;
+    readonly nc_prop: number;
     /** c2 constructor*/
     constructor(a: number);
 }
@@ -339,10 +339,10 @@ declare class c3 extends c2 {
     /** c3 f1*/
     f1(): void;
     /** c3 prop*/
-    prop: number;
+    readonly prop: number;
     nc_p1: number;
     nc_f1(): void;
-    nc_prop: number;
+    readonly nc_prop: number;
 }
 declare var c2_i: c2;
 declare var c3_i: c3;
diff --git a/tests/baselines/reference/declFileAccessors.js b/tests/baselines/reference/declFileAccessors.js
index e3616c79e3..2bd51bfbfb 100644
--- a/tests/baselines/reference/declFileAccessors.js
+++ b/tests/baselines/reference/declFileAccessors.js
@@ -284,7 +284,7 @@ export declare class c1 {
     nc_p3: number;
     private nc_pp3;
     static nc_s3: string;
-    onlyGetter: number;
+    readonly onlyGetter: number;
     onlySetter: number;
 }
 //// [declFileAccessors_1.d.ts]
@@ -302,6 +302,6 @@ declare class c2 {
     nc_p3: number;
     private nc_pp3;
     static nc_s3: string;
-    onlyGetter: number;
+    readonly onlyGetter: number;
     onlySetter: number;
 }
diff --git a/tests/baselines/reference/declFilePrivateStatic.js b/tests/baselines/reference/declFilePrivateStatic.js
index dd81d94b3c..30cd85444c 100644
--- a/tests/baselines/reference/declFilePrivateStatic.js
+++ b/tests/baselines/reference/declFilePrivateStatic.js
@@ -52,8 +52,8 @@ declare class C {
     static y: number;
     private static a();
     static b(): void;
-    private static c;
-    static d: number;
+    private static readonly c;
+    static readonly d: number;
     private static e;
     static f: any;
 }
diff --git a/tests/baselines/reference/declarationEmit_protectedMembers.js b/tests/baselines/reference/declarationEmit_protectedMembers.js
index 5aad004939..192f0647ed 100644
--- a/tests/baselines/reference/declarationEmit_protectedMembers.js
+++ b/tests/baselines/reference/declarationEmit_protectedMembers.js
@@ -135,7 +135,7 @@ declare class C1 {
     protected static sx: number;
     protected static sf(): number;
     protected static staticSetter: number;
-    protected static staticGetter: number;
+    protected static readonly staticGetter: number;
 }
 declare class C2 extends C1 {
     protected f(): number;
@@ -146,7 +146,7 @@ declare class C3 extends C2 {
     static sx: number;
     f(): number;
     static sf(): number;
-    static staticGetter: number;
+    static readonly staticGetter: number;
 }
 declare class C4 {
     protected a: number;
diff --git a/tests/baselines/reference/deduplicateImportsInSystem.errors.txt b/tests/baselines/reference/deduplicateImportsInSystem.errors.txt
new file mode 100644
index 0000000000..d1bfe88160
--- /dev/null
+++ b/tests/baselines/reference/deduplicateImportsInSystem.errors.txt
@@ -0,0 +1,32 @@
+tests/cases/compiler/deduplicateImportsInSystem.ts(1,17): error TS2307: Cannot find module 'f1'.
+tests/cases/compiler/deduplicateImportsInSystem.ts(2,17): error TS2307: Cannot find module 'f2'.
+tests/cases/compiler/deduplicateImportsInSystem.ts(3,17): error TS2307: Cannot find module 'f3'.
+tests/cases/compiler/deduplicateImportsInSystem.ts(4,17): error TS2307: Cannot find module 'f2'.
+tests/cases/compiler/deduplicateImportsInSystem.ts(5,17): error TS2307: Cannot find module 'f2'.
+tests/cases/compiler/deduplicateImportsInSystem.ts(6,17): error TS2307: Cannot find module 'f1'.
+tests/cases/compiler/deduplicateImportsInSystem.ts(8,1): error TS2304: Cannot find name 'console'.
+
+
+==== tests/cases/compiler/deduplicateImportsInSystem.ts (7 errors) ====
+    import {A} from "f1";
+                    ~~~~
+!!! error TS2307: Cannot find module 'f1'.
+    import {B} from "f2";
+                    ~~~~
+!!! error TS2307: Cannot find module 'f2'.
+    import {C} from "f3";
+                    ~~~~
+!!! error TS2307: Cannot find module 'f3'.
+    import {D} from 'f2';
+                    ~~~~
+!!! error TS2307: Cannot find module 'f2'.
+    import {E} from "f2";
+                    ~~~~
+!!! error TS2307: Cannot find module 'f2'.
+    import {F} from 'f1';
+                    ~~~~
+!!! error TS2307: Cannot find module 'f1'.
+    
+    console.log(A + B + C + D + E + F)
+    ~~~~~~~
+!!! error TS2304: Cannot find name 'console'.
\ No newline at end of file
diff --git a/tests/baselines/reference/deduplicateImportsInSystem.js b/tests/baselines/reference/deduplicateImportsInSystem.js
new file mode 100644
index 0000000000..956d293cad
--- /dev/null
+++ b/tests/baselines/reference/deduplicateImportsInSystem.js
@@ -0,0 +1,33 @@
+//// [deduplicateImportsInSystem.ts]
+import {A} from "f1";
+import {B} from "f2";
+import {C} from "f3";
+import {D} from 'f2';
+import {E} from "f2";
+import {F} from 'f1';
+
+console.log(A + B + C + D + E + F)
+
+//// [deduplicateImportsInSystem.js]
+System.register(["f1", "f2", "f3"], function(exports_1) {
+    "use strict";
+    var f1_1, f2_1, f3_1, f2_2, f2_3, f1_2;
+    return {
+        setters:[
+            function (f1_1_1) {
+                f1_1 = f1_1_1;
+                f1_2 = f1_1_1;
+            },
+            function (f2_1_1) {
+                f2_1 = f2_1_1;
+                f2_2 = f2_1_1;
+                f2_3 = f2_1_1;
+            },
+            function (f3_1_1) {
+                f3_1 = f3_1_1;
+            }],
+        execute: function() {
+            console.log(f1_1.A + f2_1.B + f3_1.C + f2_2.D + f2_3.E + f1_2.F);
+        }
+    }
+});
diff --git a/tests/baselines/reference/giant.js b/tests/baselines/reference/giant.js
index 2a04541ef2..149a975d41 100644
--- a/tests/baselines/reference/giant.js
+++ b/tests/baselines/reference/giant.js
@@ -1120,11 +1120,11 @@ export declare class eC {
     pF(): void;
     private rF();
     pgF(): void;
-    pgF: any;
+    readonly pgF: any;
     psF(param: any): void;
     psF: any;
     private rgF();
-    private rgF;
+    private readonly rgF;
     private rsF(param);
     private rsF;
     static tV: any;
@@ -1132,7 +1132,7 @@ export declare class eC {
     static tsF(param: any): void;
     static tsF: any;
     static tgF(): void;
-    static tgF: any;
+    static readonly tgF: any;
 }
 export interface eI {
     (): any;
@@ -1172,11 +1172,11 @@ export declare module eM {
         pF(): void;
         private rF();
         pgF(): void;
-        pgF: any;
+        readonly pgF: any;
         psF(param: any): void;
         psF: any;
         private rgF();
-        private rgF;
+        private readonly rgF;
         private rsF(param);
         private rsF;
         static tV: any;
@@ -1184,7 +1184,7 @@ export declare module eM {
         static tsF(param: any): void;
         static tsF: any;
         static tgF(): void;
-        static tgF: any;
+        static readonly tgF: any;
     }
     interface eI {
         (): any;
@@ -1239,11 +1239,11 @@ export declare module eM {
         pF(): void;
         private rF();
         pgF(): void;
-        pgF: any;
+        readonly pgF: any;
         psF(param: any): void;
         psF: any;
         private rgF();
-        private rgF;
+        private readonly rgF;
         private rsF(param);
         private rsF;
         static tV: any;
@@ -1251,7 +1251,7 @@ export declare module eM {
         static tsF(param: any): void;
         static tsF: any;
         static tgF(): void;
-        static tgF: any;
+        static readonly tgF: any;
     }
     module eaM {
         var V: any;
@@ -1281,11 +1281,11 @@ export declare class eaC {
     pF(): void;
     private rF();
     pgF(): void;
-    pgF: any;
+    readonly pgF: any;
     psF(param: any): void;
     psF: any;
     private rgF();
-    private rgF;
+    private readonly rgF;
     private rsF(param);
     private rsF;
     static tV: any;
@@ -1293,7 +1293,7 @@ export declare class eaC {
     static tsF(param: any): void;
     static tsF: any;
     static tgF(): void;
-    static tgF: any;
+    static readonly tgF: any;
 }
 export declare module eaM {
     var V: any;
diff --git a/tests/baselines/reference/isDeclarationVisibleNodeKinds.js b/tests/baselines/reference/isDeclarationVisibleNodeKinds.js
index 99e1ac72ac..e24032eb85 100644
--- a/tests/baselines/reference/isDeclarationVisibleNodeKinds.js
+++ b/tests/baselines/reference/isDeclarationVisibleNodeKinds.js
@@ -193,7 +193,7 @@ declare module schema {
 }
 declare module schema {
     class T {
-        createValidator9: <T>(data: T) => T;
+        readonly createValidator9: <T>(data: T) => T;
         createValidator10: <T>(data: T) => T;
     }
 }
diff --git a/tests/baselines/reference/moduledecl.js b/tests/baselines/reference/moduledecl.js
index 2e765e512d..f4efbadbf3 100644
--- a/tests/baselines/reference/moduledecl.js
+++ b/tests/baselines/reference/moduledecl.js
@@ -459,10 +459,10 @@ declare module exportTests {
     class C3_public {
         private getC2_private();
         private setC2_private(arg);
-        private c2;
+        private readonly c2;
         getC1_public(): C1_public;
         setC1_public(arg: C1_public): void;
-        c1: C1_public;
+        readonly c1: C1_public;
     }
 }
 declare module mAmbient {
diff --git a/tests/baselines/reference/readonlyInDeclarationFile.js b/tests/baselines/reference/readonlyInDeclarationFile.js
new file mode 100644
index 0000000000..71e48272ec
--- /dev/null
+++ b/tests/baselines/reference/readonlyInDeclarationFile.js
@@ -0,0 +1,180 @@
+//// [readonlyInDeclarationFile.ts]
+
+interface Foo {
+    readonly x: number;
+    readonly [x: string]: Object;
+}
+
+class C {
+    readonly [x: string]: Object;
+    private readonly a1: number;
+    protected readonly a2: number;
+    public readonly a3: number;
+    private get b1() { return 1 }
+    protected get b2() { return 1 }
+    public get b3() { return 1 }
+    private get c1() { return 1 }
+    private set c1(value) { }
+    protected get c2() { return 1 }
+    protected set c2(value) { }
+    public get c3() { return 1 }
+    public set c3(value) { }
+    private static readonly s1: number;
+    protected static readonly s2: number;
+    public static readonly s3: number;
+    private static get t1() { return 1 }
+    protected static get t2() { return 1 }
+    public static get t3() { return 1 }
+    private static get u1() { return 1 }
+    private static set u1(value) { }
+    protected static get u2() { return 1 }
+    protected static set u2(value) { }
+    public static get u3() { return 1 }
+    public static set u3(value) { }
+}
+
+var z: {
+    readonly a: string;
+    readonly [x: string]: Object;
+}
+
+function f() {
+    return {
+        get x() { return 1; },
+        get y() { return 1; },
+        set y(value) { }
+    }
+}
+
+function g() {
+    var x: {
+        readonly a: string;
+        readonly [x: string]: Object;
+    }
+    return x;
+}
+
+//// [readonlyInDeclarationFile.js]
+var C = (function () {
+    function C() {
+    }
+    Object.defineProperty(C.prototype, "b1", {
+        get: function () { return 1; },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C.prototype, "b2", {
+        get: function () { return 1; },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C.prototype, "b3", {
+        get: function () { return 1; },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C.prototype, "c1", {
+        get: function () { return 1; },
+        set: function (value) { },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C.prototype, "c2", {
+        get: function () { return 1; },
+        set: function (value) { },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C.prototype, "c3", {
+        get: function () { return 1; },
+        set: function (value) { },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C, "t1", {
+        get: function () { return 1; },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C, "t2", {
+        get: function () { return 1; },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C, "t3", {
+        get: function () { return 1; },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C, "u1", {
+        get: function () { return 1; },
+        set: function (value) { },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C, "u2", {
+        get: function () { return 1; },
+        set: function (value) { },
+        enumerable: true,
+        configurable: true
+    });
+    Object.defineProperty(C, "u3", {
+        get: function () { return 1; },
+        set: function (value) { },
+        enumerable: true,
+        configurable: true
+    });
+    return C;
+}());
+var z;
+function f() {
+    return {
+        get x() { return 1; },
+        get y() { return 1; },
+        set y(value) { }
+    };
+}
+function g() {
+    var x;
+    return x;
+}
+
+
+//// [readonlyInDeclarationFile.d.ts]
+interface Foo {
+    readonly x: number;
+    readonly [x: string]: Object;
+}
+declare class C {
+    readonly [x: string]: Object;
+    private readonly a1;
+    protected readonly a2: number;
+    readonly a3: number;
+    private readonly b1;
+    protected readonly b2: number;
+    readonly b3: number;
+    private c1;
+    protected c2: number;
+    c3: number;
+    private static readonly s1;
+    protected static readonly s2: number;
+    static readonly s3: number;
+    private static readonly t1;
+    protected static readonly t2: number;
+    static readonly t3: number;
+    private static u1;
+    protected static u2: number;
+    static u3: number;
+}
+declare var z: {
+    readonly a: string;
+    readonly [x: string]: Object;
+};
+declare function f(): {
+    readonly x: number;
+    y: number;
+};
+declare function g(): {
+    readonly [x: string]: Object;
+    readonly a: string;
+};
diff --git a/tests/baselines/reference/readonlyInDeclarationFile.symbols b/tests/baselines/reference/readonlyInDeclarationFile.symbols
new file mode 100644
index 0000000000..af979e4dac
--- /dev/null
+++ b/tests/baselines/reference/readonlyInDeclarationFile.symbols
@@ -0,0 +1,142 @@
+=== tests/cases/compiler/readonlyInDeclarationFile.ts ===
+
+interface Foo {
+>Foo : Symbol(Foo, Decl(readonlyInDeclarationFile.ts, 0, 0))
+
+    readonly x: number;
+>x : Symbol(x, Decl(readonlyInDeclarationFile.ts, 1, 15))
+
+    readonly [x: string]: Object;
+>x : Symbol(x, Decl(readonlyInDeclarationFile.ts, 3, 14))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+}
+
+class C {
+>C : Symbol(C, Decl(readonlyInDeclarationFile.ts, 4, 1))
+
+    readonly [x: string]: Object;
+>x : Symbol(x, Decl(readonlyInDeclarationFile.ts, 7, 14))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+    private readonly a1: number;
+>a1 : Symbol(a1, Decl(readonlyInDeclarationFile.ts, 7, 33))
+
+    protected readonly a2: number;
+>a2 : Symbol(a2, Decl(readonlyInDeclarationFile.ts, 8, 32))
+
+    public readonly a3: number;
+>a3 : Symbol(a3, Decl(readonlyInDeclarationFile.ts, 9, 34))
+
+    private get b1() { return 1 }
+>b1 : Symbol(b1, Decl(readonlyInDeclarationFile.ts, 10, 31))
+
+    protected get b2() { return 1 }
+>b2 : Symbol(b2, Decl(readonlyInDeclarationFile.ts, 11, 33))
+
+    public get b3() { return 1 }
+>b3 : Symbol(b3, Decl(readonlyInDeclarationFile.ts, 12, 35))
+
+    private get c1() { return 1 }
+>c1 : Symbol(c1, Decl(readonlyInDeclarationFile.ts, 13, 32), Decl(readonlyInDeclarationFile.ts, 14, 33))
+
+    private set c1(value) { }
+>c1 : Symbol(c1, Decl(readonlyInDeclarationFile.ts, 13, 32), Decl(readonlyInDeclarationFile.ts, 14, 33))
+>value : Symbol(value, Decl(readonlyInDeclarationFile.ts, 15, 19))
+
+    protected get c2() { return 1 }
+>c2 : Symbol(c2, Decl(readonlyInDeclarationFile.ts, 15, 29), Decl(readonlyInDeclarationFile.ts, 16, 35))
+
+    protected set c2(value) { }
+>c2 : Symbol(c2, Decl(readonlyInDeclarationFile.ts, 15, 29), Decl(readonlyInDeclarationFile.ts, 16, 35))
+>value : Symbol(value, Decl(readonlyInDeclarationFile.ts, 17, 21))
+
+    public get c3() { return 1 }
+>c3 : Symbol(c3, Decl(readonlyInDeclarationFile.ts, 17, 31), Decl(readonlyInDeclarationFile.ts, 18, 32))
+
+    public set c3(value) { }
+>c3 : Symbol(c3, Decl(readonlyInDeclarationFile.ts, 17, 31), Decl(readonlyInDeclarationFile.ts, 18, 32))
+>value : Symbol(value, Decl(readonlyInDeclarationFile.ts, 19, 18))
+
+    private static readonly s1: number;
+>s1 : Symbol(C.s1, Decl(readonlyInDeclarationFile.ts, 19, 28))
+
+    protected static readonly s2: number;
+>s2 : Symbol(C.s2, Decl(readonlyInDeclarationFile.ts, 20, 39))
+
+    public static readonly s3: number;
+>s3 : Symbol(C.s3, Decl(readonlyInDeclarationFile.ts, 21, 41))
+
+    private static get t1() { return 1 }
+>t1 : Symbol(C.t1, Decl(readonlyInDeclarationFile.ts, 22, 38))
+
+    protected static get t2() { return 1 }
+>t2 : Symbol(C.t2, Decl(readonlyInDeclarationFile.ts, 23, 40))
+
+    public static get t3() { return 1 }
+>t3 : Symbol(C.t3, Decl(readonlyInDeclarationFile.ts, 24, 42))
+
+    private static get u1() { return 1 }
+>u1 : Symbol(C.u1, Decl(readonlyInDeclarationFile.ts, 25, 39), Decl(readonlyInDeclarationFile.ts, 26, 40))
+
+    private static set u1(value) { }
+>u1 : Symbol(C.u1, Decl(readonlyInDeclarationFile.ts, 25, 39), Decl(readonlyInDeclarationFile.ts, 26, 40))
+>value : Symbol(value, Decl(readonlyInDeclarationFile.ts, 27, 26))
+
+    protected static get u2() { return 1 }
+>u2 : Symbol(C.u2, Decl(readonlyInDeclarationFile.ts, 27, 36), Decl(readonlyInDeclarationFile.ts, 28, 42))
+
+    protected static set u2(value) { }
+>u2 : Symbol(C.u2, Decl(readonlyInDeclarationFile.ts, 27, 36), Decl(readonlyInDeclarationFile.ts, 28, 42))
+>value : Symbol(value, Decl(readonlyInDeclarationFile.ts, 29, 28))
+
+    public static get u3() { return 1 }
+>u3 : Symbol(C.u3, Decl(readonlyInDeclarationFile.ts, 29, 38), Decl(readonlyInDeclarationFile.ts, 30, 39))
+
+    public static set u3(value) { }
+>u3 : Symbol(C.u3, Decl(readonlyInDeclarationFile.ts, 29, 38), Decl(readonlyInDeclarationFile.ts, 30, 39))
+>value : Symbol(value, Decl(readonlyInDeclarationFile.ts, 31, 25))
+}
+
+var z: {
+>z : Symbol(z, Decl(readonlyInDeclarationFile.ts, 34, 3))
+
+    readonly a: string;
+>a : Symbol(a, Decl(readonlyInDeclarationFile.ts, 34, 8))
+
+    readonly [x: string]: Object;
+>x : Symbol(x, Decl(readonlyInDeclarationFile.ts, 36, 14))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+}
+
+function f() {
+>f : Symbol(f, Decl(readonlyInDeclarationFile.ts, 37, 1))
+
+    return {
+        get x() { return 1; },
+>x : Symbol(x, Decl(readonlyInDeclarationFile.ts, 40, 12))
+
+        get y() { return 1; },
+>y : Symbol(y, Decl(readonlyInDeclarationFile.ts, 41, 30), Decl(readonlyInDeclarationFile.ts, 42, 30))
+
+        set y(value) { }
+>y : Symbol(y, Decl(readonlyInDeclarationFile.ts, 41, 30), Decl(readonlyInDeclarationFile.ts, 42, 30))
+>value : Symbol(value, Decl(readonlyInDeclarationFile.ts, 43, 14))
+    }
+}
+
+function g() {
+>g : Symbol(g, Decl(readonlyInDeclarationFile.ts, 45, 1))
+
+    var x: {
+>x : Symbol(x, Decl(readonlyInDeclarationFile.ts, 48, 7))
+
+        readonly a: string;
+>a : Symbol(a, Decl(readonlyInDeclarationFile.ts, 48, 12))
+
+        readonly [x: string]: Object;
+>x : Symbol(x, Decl(readonlyInDeclarationFile.ts, 50, 18))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+    }
+    return x;
+>x : Symbol(x, Decl(readonlyInDeclarationFile.ts, 48, 7))
+}
diff --git a/tests/baselines/reference/readonlyInDeclarationFile.types b/tests/baselines/reference/readonlyInDeclarationFile.types
new file mode 100644
index 0000000000..7a3e11577c
--- /dev/null
+++ b/tests/baselines/reference/readonlyInDeclarationFile.types
@@ -0,0 +1,158 @@
+=== tests/cases/compiler/readonlyInDeclarationFile.ts ===
+
+interface Foo {
+>Foo : Foo
+
+    readonly x: number;
+>x : number
+
+    readonly [x: string]: Object;
+>x : string
+>Object : Object
+}
+
+class C {
+>C : C
+
+    readonly [x: string]: Object;
+>x : string
+>Object : Object
+
+    private readonly a1: number;
+>a1 : number
+
+    protected readonly a2: number;
+>a2 : number
+
+    public readonly a3: number;
+>a3 : number
+
+    private get b1() { return 1 }
+>b1 : number
+>1 : number
+
+    protected get b2() { return 1 }
+>b2 : number
+>1 : number
+
+    public get b3() { return 1 }
+>b3 : number
+>1 : number
+
+    private get c1() { return 1 }
+>c1 : number
+>1 : number
+
+    private set c1(value) { }
+>c1 : number
+>value : number
+
+    protected get c2() { return 1 }
+>c2 : number
+>1 : number
+
+    protected set c2(value) { }
+>c2 : number
+>value : number
+
+    public get c3() { return 1 }
+>c3 : number
+>1 : number
+
+    public set c3(value) { }
+>c3 : number
+>value : number
+
+    private static readonly s1: number;
+>s1 : number
+
+    protected static readonly s2: number;
+>s2 : number
+
+    public static readonly s3: number;
+>s3 : number
+
+    private static get t1() { return 1 }
+>t1 : number
+>1 : number
+
+    protected static get t2() { return 1 }
+>t2 : number
+>1 : number
+
+    public static get t3() { return 1 }
+>t3 : number
+>1 : number
+
+    private static get u1() { return 1 }
+>u1 : number
+>1 : number
+
+    private static set u1(value) { }
+>u1 : number
+>value : number
+
+    protected static get u2() { return 1 }
+>u2 : number
+>1 : number
+
+    protected static set u2(value) { }
+>u2 : number
+>value : number
+
+    public static get u3() { return 1 }
+>u3 : number
+>1 : number
+
+    public static set u3(value) { }
+>u3 : number
+>value : number
+}
+
+var z: {
+>z : { readonly [x: string]: Object; readonly a: string; }
+
+    readonly a: string;
+>a : string
+
+    readonly [x: string]: Object;
+>x : string
+>Object : Object
+}
+
+function f() {
+>f : () => { readonly x: number; y: number; }
+
+    return {
+>{        get x() { return 1; },        get y() { return 1; },        set y(value) { }    } : { readonly x: number; y: number; }
+
+        get x() { return 1; },
+>x : number
+>1 : number
+
+        get y() { return 1; },
+>y : number
+>1 : number
+
+        set y(value) { }
+>y : number
+>value : number
+    }
+}
+
+function g() {
+>g : () => { readonly [x: string]: Object; readonly a: string; }
+
+    var x: {
+>x : { readonly [x: string]: Object; readonly a: string; }
+
+        readonly a: string;
+>a : string
+
+        readonly [x: string]: Object;
+>x : string
+>Object : Object
+    }
+    return x;
+>x : { readonly [x: string]: Object; readonly a: string; }
+}
diff --git a/tests/baselines/reference/symbolDeclarationEmit13.js b/tests/baselines/reference/symbolDeclarationEmit13.js
index 8111672866..bbd2c15cfc 100644
--- a/tests/baselines/reference/symbolDeclarationEmit13.js
+++ b/tests/baselines/reference/symbolDeclarationEmit13.js
@@ -13,6 +13,6 @@ class C {
 
 //// [symbolDeclarationEmit13.d.ts]
 declare class C {
-    [Symbol.toPrimitive]: string;
+    readonly [Symbol.toPrimitive]: string;
     [Symbol.toStringTag]: any;
 }
diff --git a/tests/baselines/reference/symbolDeclarationEmit14.js b/tests/baselines/reference/symbolDeclarationEmit14.js
index b8a6b3e409..d4ae3eeb43 100644
--- a/tests/baselines/reference/symbolDeclarationEmit14.js
+++ b/tests/baselines/reference/symbolDeclarationEmit14.js
@@ -13,6 +13,6 @@ class C {
 
 //// [symbolDeclarationEmit14.d.ts]
 declare class C {
-    [Symbol.toPrimitive]: string;
-    [Symbol.toStringTag]: string;
+    readonly [Symbol.toPrimitive]: string;
+    readonly [Symbol.toStringTag]: string;
 }
diff --git a/tests/baselines/reference/typeGuardOfFormThisMember.js b/tests/baselines/reference/typeGuardOfFormThisMember.js
index 2f983d2cdf..9d71613ed8 100644
--- a/tests/baselines/reference/typeGuardOfFormThisMember.js
+++ b/tests/baselines/reference/typeGuardOfFormThisMember.js
@@ -170,7 +170,7 @@ declare namespace Test {
         path: string;
         isFSO: this is FileSystemObject;
         isFile: this is File;
-        isDirectory: this is Directory;
+        readonly isDirectory: this is Directory;
         isNetworked: this is (Networked & this);
         constructor(path: string);
     }
diff --git a/tests/baselines/reference/typeGuardOfFormThisMemberErrors.js b/tests/baselines/reference/typeGuardOfFormThisMemberErrors.js
index 6f681ab09c..5991fdd316 100644
--- a/tests/baselines/reference/typeGuardOfFormThisMemberErrors.js
+++ b/tests/baselines/reference/typeGuardOfFormThisMemberErrors.js
@@ -95,7 +95,7 @@ declare namespace Test {
         path: string;
         isFSO: this is FileSystemObject;
         isFile: this is File;
-        isDirectory: this is Directory;
+        readonly isDirectory: this is Directory;
         isNetworked: this is (Networked & this);
         constructor(path: string);
     }
diff --git a/tests/cases/compiler/deduplicateImportsInSystem.ts b/tests/cases/compiler/deduplicateImportsInSystem.ts
new file mode 100644
index 0000000000..2fcbc16be0
--- /dev/null
+++ b/tests/cases/compiler/deduplicateImportsInSystem.ts
@@ -0,0 +1,9 @@
+// @module: system
+import {A} from "f1";
+import {B} from "f2";
+import {C} from "f3";
+import {D} from 'f2';
+import {E} from "f2";
+import {F} from 'f1';
+
+console.log(A + B + C + D + E + F)
\ No newline at end of file
diff --git a/tests/cases/compiler/readonlyInDeclarationFile.ts b/tests/cases/compiler/readonlyInDeclarationFile.ts
new file mode 100644
index 0000000000..03e643782f
--- /dev/null
+++ b/tests/cases/compiler/readonlyInDeclarationFile.ts
@@ -0,0 +1,56 @@
+// @target: es5
+// @declaration: true
+
+interface Foo {
+    readonly x: number;
+    readonly [x: string]: Object;
+}
+
+class C {
+    readonly [x: string]: Object;
+    private readonly a1: number;
+    protected readonly a2: number;
+    public readonly a3: number;
+    private get b1() { return 1 }
+    protected get b2() { return 1 }
+    public get b3() { return 1 }
+    private get c1() { return 1 }
+    private set c1(value) { }
+    protected get c2() { return 1 }
+    protected set c2(value) { }
+    public get c3() { return 1 }
+    public set c3(value) { }
+    private static readonly s1: number;
+    protected static readonly s2: number;
+    public static readonly s3: number;
+    private static get t1() { return 1 }
+    protected static get t2() { return 1 }
+    public static get t3() { return 1 }
+    private static get u1() { return 1 }
+    private static set u1(value) { }
+    protected static get u2() { return 1 }
+    protected static set u2(value) { }
+    public static get u3() { return 1 }
+    public static set u3(value) { }
+}
+
+var z: {
+    readonly a: string;
+    readonly [x: string]: Object;
+}
+
+function f() {
+    return {
+        get x() { return 1; },
+        get y() { return 1; },
+        set y(value) { }
+    }
+}
+
+function g() {
+    var x: {
+        readonly a: string;
+        readonly [x: string]: Object;
+    }
+    return x;
+}
\ No newline at end of file
diff --git a/tests/cases/fourslash/getJavaScriptCompletions18.ts b/tests/cases/fourslash/getJavaScriptCompletions18.ts
new file mode 100644
index 0000000000..a30d4943f4
--- /dev/null
+++ b/tests/cases/fourslash/getJavaScriptCompletions18.ts
@@ -0,0 +1,21 @@
+/// <reference path="fourslash.ts" />
+
+// @allowNonTsExtensions: true
+// @Filename: file.js
+//// /**
+////   * @param {number} a
+////   * @param {string} b
+//// */
+//// exports.foo = function(a, b) {
+//// 	a/*a*/;
+//// 	b/*b*/
+//// };
+
+goTo.marker('a');
+edit.insert('.');
+verify.completionListContains('toFixed', undefined, undefined, 'method');
+
+
+goTo.marker('b');
+edit.insert('.');
+verify.completionListContains('substr', undefined, undefined, 'method');
diff --git a/tests/cases/fourslash/getJavaScriptCompletions19.ts b/tests/cases/fourslash/getJavaScriptCompletions19.ts
new file mode 100644
index 0000000000..5a361930e8
--- /dev/null
+++ b/tests/cases/fourslash/getJavaScriptCompletions19.ts
@@ -0,0 +1,25 @@
+/// <reference path="fourslash.ts" />
+
+// @allowNonTsExtensions: true
+// @Filename: file.js
+//// function fn() {
+//// 	if (foo) {
+//// 		return 0;
+//// 	} else {
+//// 		return '0';
+//// 	}
+//// }
+//// let x = fn();
+//// if(typeof x === 'string') {
+//// 	x/*str*/
+//// } else {
+//// 	x/*num*/
+//// }
+
+goTo.marker('str');
+edit.insert('.');
+verify.completionListContains('substr', undefined, undefined, 'method');
+
+goTo.marker('num');
+edit.insert('.');
+verify.completionListContains('toFixed', undefined, undefined, 'method');
diff --git a/tests/cases/fourslash/renameCrossJsTs01.ts b/tests/cases/fourslash/renameCrossJsTs01.ts
new file mode 100644
index 0000000000..52cb4c587d
--- /dev/null
+++ b/tests/cases/fourslash/renameCrossJsTs01.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+
+// @allowJs: true
+// @Filename: a.js
+////exports.[|area|] = function (r) { return r * r; }
+
+// @Filename: b.ts
+////import { [|area|] } from './a';
+////var t = /**/[|area|](10);
+
+goTo.marker();
+verify.renameLocations( /*findInStrings*/ false, /*findInComments*/ false);
\ No newline at end of file
diff --git a/tests/cases/fourslash/renameCrossJsTs02.ts b/tests/cases/fourslash/renameCrossJsTs02.ts
new file mode 100644
index 0000000000..7ff1ae96ff
--- /dev/null
+++ b/tests/cases/fourslash/renameCrossJsTs02.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+
+// @allowJs: true
+// @Filename: a.js
+////exports./**/[|area|] = function (r) { return r * r; }
+
+// @Filename: b.ts
+////import { [|area|] } from './a';
+////var t = [|area|](10);
+
+goTo.marker();
+verify.renameLocations( /*findInStrings*/ false, /*findInComments*/ false);
\ No newline at end of file
diff --git a/tests/cases/fourslash/renameJsExports01.ts b/tests/cases/fourslash/renameJsExports01.ts
new file mode 100644
index 0000000000..923d30eedf
--- /dev/null
+++ b/tests/cases/fourslash/renameJsExports01.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+
+// @allowJs: true
+// @Filename: a.js
+////exports.[|area|] = function (r) { return r * r; }
+
+// @Filename: b.js
+////var mod = require('./a');
+////var t = mod./**/[|area|](10);
+
+goTo.marker();
+verify.renameLocations( /*findInStrings*/ false, /*findInComments*/ false);
\ No newline at end of file
diff --git a/tests/cases/fourslash/renameJsExports02.ts b/tests/cases/fourslash/renameJsExports02.ts
new file mode 100644
index 0000000000..86b0471dc1
--- /dev/null
+++ b/tests/cases/fourslash/renameJsExports02.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+
+// @allowJs: true
+// @Filename: a.js
+////exports./**/[|area|] = function (r) { return r * r; }
+
+// @Filename: b.js
+////var mod = require('./a');
+////var t = mod.[|area|](10);
+
+goTo.marker();
+verify.renameLocations( /*findInStrings*/ false, /*findInComments*/ false);
\ No newline at end of file
diff --git a/tests/cases/fourslash/renameJsPrototypeProperty01.ts b/tests/cases/fourslash/renameJsPrototypeProperty01.ts
new file mode 100644
index 0000000000..f756f57edb
--- /dev/null
+++ b/tests/cases/fourslash/renameJsPrototypeProperty01.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+
+// @allowJs: true
+// @Filename: a.js
+////function bar() {
+////}
+////bar.prototype.[|x|] = 10;
+////var t = new bar();
+////t./**/[|x|] = 11;
+
+goTo.marker();
+verify.renameLocations( /*findInStrings*/ false, /*findInComments*/ false);
\ No newline at end of file
diff --git a/tests/cases/fourslash/renameJsPrototypeProperty02.ts b/tests/cases/fourslash/renameJsPrototypeProperty02.ts
new file mode 100644
index 0000000000..721dc312eb
--- /dev/null
+++ b/tests/cases/fourslash/renameJsPrototypeProperty02.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+
+// @allowJs: true
+// @Filename: a.js
+////function bar() {
+////}
+////bar.prototype./**/[|x|] = 10;
+////var t = new bar();
+////t.[|x|] = 11;
+
+goTo.marker();
+verify.renameLocations( /*findInStrings*/ false, /*findInComments*/ false);
\ No newline at end of file
diff --git a/tests/cases/fourslash/renameJsThisProperty01.ts b/tests/cases/fourslash/renameJsThisProperty01.ts
new file mode 100644
index 0000000000..91338e0431
--- /dev/null
+++ b/tests/cases/fourslash/renameJsThisProperty01.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+
+// @allowJs: true
+// @Filename: a.js
+////function bar() {
+////    this.[|x|] = 10;
+////}
+////var t = new bar();
+////t./**/[|x|] = 11;
+
+goTo.marker();
+verify.renameLocations( /*findInStrings*/ false, /*findInComments*/ false);
\ No newline at end of file
diff --git a/tests/cases/fourslash/renameJsThisProperty02.ts b/tests/cases/fourslash/renameJsThisProperty02.ts
new file mode 100644
index 0000000000..8398507c9c
--- /dev/null
+++ b/tests/cases/fourslash/renameJsThisProperty02.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+
+// @allowJs: true
+// @Filename: a.js
+////function bar() {
+////    this./**/[|x|] = 10;
+////}
+////var t = new bar();
+////t.[|x|] = 11;
+
+goTo.marker();
+verify.renameLocations( /*findInStrings*/ false, /*findInComments*/ false);
\ No newline at end of file