diff --git a/tests/baselines/reference/importsImplicitlyReadonly.errors.txt b/tests/baselines/reference/importsImplicitlyReadonly.errors.txt
new file mode 100644
index 00000000000..cc6e1918020
--- /dev/null
+++ b/tests/baselines/reference/importsImplicitlyReadonly.errors.txt
@@ -0,0 +1,34 @@
+tests/cases/conformance/externalModules/b.ts(6,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/externalModules/b.ts(7,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/externalModules/b.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/externalModules/b.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+
+
+==== tests/cases/conformance/externalModules/b.ts (4 errors) ====
+    import { x, y } from "./a";
+    import * as a1 from "./a";
+    import a2 = require("./a");
+    const a3 = a1;
+    
+    x = 1;     // Error
+    ~
+!!! error TS2364: Invalid left-hand side of assignment expression.
+    y = 1;     // Error
+    ~
+!!! error TS2364: Invalid left-hand side of assignment expression.
+    a1.x = 1;  // Error
+    ~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+    a1.y = 1;  // Error
+    ~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+    a2.x = 1;
+    a2.y = 1;
+    a3.x = 1;
+    a3.y = 1;
+==== tests/cases/conformance/externalModules/a.ts (0 errors) ====
+    
+    export var x = 1;
+    var y = 1;
+    export { y };
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/importsImplicitlyReadonly.js b/tests/baselines/reference/importsImplicitlyReadonly.js
new file mode 100644
index 00000000000..4630de598cc
--- /dev/null
+++ b/tests/baselines/reference/importsImplicitlyReadonly.js
@@ -0,0 +1,42 @@
+//// [tests/cases/conformance/externalModules/importsImplicitlyReadonly.ts] ////
+
+//// [a.ts]
+
+export var x = 1;
+var y = 1;
+export { y };
+
+//// [b.ts]
+import { x, y } from "./a";
+import * as a1 from "./a";
+import a2 = require("./a");
+const a3 = a1;
+
+x = 1;     // Error
+y = 1;     // Error
+a1.x = 1;  // Error
+a1.y = 1;  // Error
+a2.x = 1;
+a2.y = 1;
+a3.x = 1;
+a3.y = 1;
+
+//// [a.js]
+"use strict";
+exports.x = 1;
+var y = 1;
+exports.y = y;
+//// [b.js]
+"use strict";
+var a_1 = require("./a");
+var a1 = require("./a");
+var a2 = require("./a");
+var a3 = a1;
+a_1.x = 1; // Error
+a_1.y = 1; // Error
+a1.x = 1; // Error
+a1.y = 1; // Error
+a2.x = 1;
+a2.y = 1;
+a3.x = 1;
+a3.y = 1;
diff --git a/tests/baselines/reference/readonlyMembers.errors.txt b/tests/baselines/reference/readonlyMembers.errors.txt
new file mode 100644
index 00000000000..7bc10aa3746
--- /dev/null
+++ b/tests/baselines/reference/readonlyMembers.errors.txt
@@ -0,0 +1,114 @@
+tests/cases/compiler/readonlyMembers.ts(7,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(17,9): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(19,13): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(20,13): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(21,13): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(25,9): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(26,9): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(27,9): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(36,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(40,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(49,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(56,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(62,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(65,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+
+
+==== tests/cases/compiler/readonlyMembers.ts (15 errors) ====
+    
+    interface X {
+        readonly a: number;
+        readonly b?: number;
+    }
+    var x: X = { a: 0 };
+    x.a = 1;  // Error
+    ~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+    x.b = 1;  // Error
+    ~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+    
+    class C {
+        readonly a: number;
+        readonly b = 1;
+        get c() { return 1 }
+        constructor() {
+            this.a = 1;  // Ok
+            this.b = 1;  // Ok
+            this.c = 1;  // Error
+            ~~~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+            const f = () => {
+                this.a = 1;  // Error
+                ~~~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                this.b = 1;  // Error
+                ~~~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                this.c = 1;  // Error
+                ~~~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+            }
+        }
+        foo() {
+            this.a = 1;  // Error
+            ~~~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+            this.b = 1;  // Error
+            ~~~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+            this.c = 1;  // Error
+            ~~~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+        }
+    }
+    
+    var o = {
+        get a() { return 1 },
+        get b() { return 1 },
+        set b(value) { }
+    };
+    o.a = 1;  // Error
+    ~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+    o.b = 1;
+    
+    var p: { readonly a: number, b: number } = { a: 1, b: 1 };
+    p.a = 1;  // Error
+    ~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+    p.b = 1;
+    var q: { a: number, b: number } = p;
+    q.a = 1;
+    q.b = 1;
+    
+    enum E {
+        A, B, C
+    }
+    E.A = 1;  // Error
+    ~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+    
+    namespace N {
+        export const a = 1;
+        export let b = 1;
+        export var c = 1;
+    }
+    N.a = 1;  // Error
+    ~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+    N.b = 1;
+    N.c = 1;
+    
+    let xx: { readonly [x: string]: string };
+    let s = xx["foo"];
+    xx["foo"] = "abc";  // Error
+    ~~~~~~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+    
+    let yy: { readonly [x: number]: string, [x: string]: string };
+    yy[1] = "abc";  // Error
+    ~~~~~
+!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+    yy["foo"] = "abc";
\ No newline at end of file
diff --git a/tests/baselines/reference/readonlyMembers.js b/tests/baselines/reference/readonlyMembers.js
new file mode 100644
index 00000000000..899c52d8626
--- /dev/null
+++ b/tests/baselines/reference/readonlyMembers.js
@@ -0,0 +1,132 @@
+//// [readonlyMembers.ts]
+
+interface X {
+    readonly a: number;
+    readonly b?: number;
+}
+var x: X = { a: 0 };
+x.a = 1;  // Error
+x.b = 1;  // Error
+
+class C {
+    readonly a: number;
+    readonly b = 1;
+    get c() { return 1 }
+    constructor() {
+        this.a = 1;  // Ok
+        this.b = 1;  // Ok
+        this.c = 1;  // Error
+        const f = () => {
+            this.a = 1;  // Error
+            this.b = 1;  // Error
+            this.c = 1;  // Error
+        }
+    }
+    foo() {
+        this.a = 1;  // Error
+        this.b = 1;  // Error
+        this.c = 1;  // Error
+    }
+}
+
+var o = {
+    get a() { return 1 },
+    get b() { return 1 },
+    set b(value) { }
+};
+o.a = 1;  // Error
+o.b = 1;
+
+var p: { readonly a: number, b: number } = { a: 1, b: 1 };
+p.a = 1;  // Error
+p.b = 1;
+var q: { a: number, b: number } = p;
+q.a = 1;
+q.b = 1;
+
+enum E {
+    A, B, C
+}
+E.A = 1;  // Error
+
+namespace N {
+    export const a = 1;
+    export let b = 1;
+    export var c = 1;
+}
+N.a = 1;  // Error
+N.b = 1;
+N.c = 1;
+
+let xx: { readonly [x: string]: string };
+let s = xx["foo"];
+xx["foo"] = "abc";  // Error
+
+let yy: { readonly [x: number]: string, [x: string]: string };
+yy[1] = "abc";  // Error
+yy["foo"] = "abc";
+
+//// [readonlyMembers.js]
+var x = { a: 0 };
+x.a = 1; // Error
+x.b = 1; // Error
+var C = (function () {
+    function C() {
+        var _this = this;
+        this.b = 1;
+        this.a = 1; // Ok
+        this.b = 1; // Ok
+        this.c = 1; // Error
+        var f = function () {
+            _this.a = 1; // Error
+            _this.b = 1; // Error
+            _this.c = 1; // Error
+        };
+    }
+    Object.defineProperty(C.prototype, "c", {
+        get: function () { return 1; },
+        enumerable: true,
+        configurable: true
+    });
+    C.prototype.foo = function () {
+        this.a = 1; // Error
+        this.b = 1; // Error
+        this.c = 1; // Error
+    };
+    return C;
+}());
+var o = {
+    get a() { return 1; },
+    get b() { return 1; },
+    set b(value) { }
+};
+o.a = 1; // Error
+o.b = 1;
+var p = { a: 1, b: 1 };
+p.a = 1; // Error
+p.b = 1;
+var q = p;
+q.a = 1;
+q.b = 1;
+var E;
+(function (E) {
+    E[E["A"] = 0] = "A";
+    E[E["B"] = 1] = "B";
+    E[E["C"] = 2] = "C";
+})(E || (E = {}));
+E.A = 1; // Error
+var N;
+(function (N) {
+    N.a = 1;
+    N.b = 1;
+    N.c = 1;
+})(N || (N = {}));
+N.a = 1; // Error
+N.b = 1;
+N.c = 1;
+var xx;
+var s = xx["foo"];
+xx["foo"] = "abc"; // Error
+var yy;
+yy[1] = "abc"; // Error
+yy["foo"] = "abc";