diff --git a/tests/baselines/reference/classExtendingBuiltinType.js b/tests/baselines/reference/classExtendingBuiltinType.js
new file mode 100644
index 00000000000..666ada39505
--- /dev/null
+++ b/tests/baselines/reference/classExtendingBuiltinType.js
@@ -0,0 +1,90 @@
+//// [classExtendingBuiltinType.ts]
+class C1 extends Object { }
+class C2 extends Function { }
+class C3 extends String { }
+class C4 extends Boolean { }
+class C5 extends Number { }
+class C6 extends Date { }
+class C7 extends RegExp { }
+class C8 extends Error { }
+class C9 extends Array { }
+class C10 extends Array<number> { }
+
+
+//// [classExtendingBuiltinType.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    __.prototype = b.prototype;
+    d.prototype = new __();
+};
+var C1 = (function (_super) {
+    __extends(C1, _super);
+    function C1() {
+        _super.apply(this, arguments);
+    }
+    return C1;
+})(Object);
+var C2 = (function (_super) {
+    __extends(C2, _super);
+    function C2() {
+        _super.apply(this, arguments);
+    }
+    return C2;
+})(Function);
+var C3 = (function (_super) {
+    __extends(C3, _super);
+    function C3() {
+        _super.apply(this, arguments);
+    }
+    return C3;
+})(String);
+var C4 = (function (_super) {
+    __extends(C4, _super);
+    function C4() {
+        _super.apply(this, arguments);
+    }
+    return C4;
+})(Boolean);
+var C5 = (function (_super) {
+    __extends(C5, _super);
+    function C5() {
+        _super.apply(this, arguments);
+    }
+    return C5;
+})(Number);
+var C6 = (function (_super) {
+    __extends(C6, _super);
+    function C6() {
+        _super.apply(this, arguments);
+    }
+    return C6;
+})(Date);
+var C7 = (function (_super) {
+    __extends(C7, _super);
+    function C7() {
+        _super.apply(this, arguments);
+    }
+    return C7;
+})(RegExp);
+var C8 = (function (_super) {
+    __extends(C8, _super);
+    function C8() {
+        _super.apply(this, arguments);
+    }
+    return C8;
+})(Error);
+var C9 = (function (_super) {
+    __extends(C9, _super);
+    function C9() {
+        _super.apply(this, arguments);
+    }
+    return C9;
+})(Array);
+var C10 = (function (_super) {
+    __extends(C10, _super);
+    function C10() {
+        _super.apply(this, arguments);
+    }
+    return C10;
+})(Array);
diff --git a/tests/baselines/reference/classExtendingBuiltinType.symbols b/tests/baselines/reference/classExtendingBuiltinType.symbols
new file mode 100644
index 00000000000..08e85be570e
--- /dev/null
+++ b/tests/baselines/reference/classExtendingBuiltinType.symbols
@@ -0,0 +1,41 @@
+=== tests/cases/conformance/classes/classDeclarations/classExtendingBuiltinType.ts ===
+class C1 extends Object { }
+>C1 : Symbol(C1, Decl(classExtendingBuiltinType.ts, 0, 0))
+>Object : Symbol(Object, Decl(lib.d.ts, 92, 1), Decl(lib.d.ts, 223, 11))
+
+class C2 extends Function { }
+>C2 : Symbol(C2, Decl(classExtendingBuiltinType.ts, 0, 27))
+>Function : Symbol(Function, Decl(lib.d.ts, 223, 38), Decl(lib.d.ts, 269, 11))
+
+class C3 extends String { }
+>C3 : Symbol(C3, Decl(classExtendingBuiltinType.ts, 1, 29))
+>String : Symbol(String, Decl(lib.d.ts, 275, 1), Decl(lib.d.ts, 443, 11))
+
+class C4 extends Boolean { }
+>C4 : Symbol(C4, Decl(classExtendingBuiltinType.ts, 2, 27))
+>Boolean : Symbol(Boolean, Decl(lib.d.ts, 443, 38), Decl(lib.d.ts, 456, 11))
+
+class C5 extends Number { }
+>C5 : Symbol(C5, Decl(classExtendingBuiltinType.ts, 3, 28))
+>Number : Symbol(Number, Decl(lib.d.ts, 456, 40), Decl(lib.d.ts, 518, 11))
+
+class C6 extends Date { }
+>C6 : Symbol(C6, Decl(classExtendingBuiltinType.ts, 4, 27))
+>Date : Symbol(Date, Decl(lib.d.ts, 633, 23), Decl(lib.d.ts, 815, 11))
+
+class C7 extends RegExp { }
+>C7 : Symbol(C7, Decl(classExtendingBuiltinType.ts, 5, 25))
+>RegExp : Symbol(RegExp, Decl(lib.d.ts, 825, 1), Decl(lib.d.ts, 876, 11))
+
+class C8 extends Error { }
+>C8 : Symbol(C8, Decl(classExtendingBuiltinType.ts, 6, 27))
+>Error : Symbol(Error, Decl(lib.d.ts, 876, 38), Decl(lib.d.ts, 889, 11))
+
+class C9 extends Array { }
+>C9 : Symbol(C9, Decl(classExtendingBuiltinType.ts, 7, 26))
+>Array : Symbol(Array, Decl(lib.d.ts, 1000, 23), Decl(lib.d.ts, 1171, 11))
+
+class C10 extends Array<number> { }
+>C10 : Symbol(C10, Decl(classExtendingBuiltinType.ts, 8, 26))
+>Array : Symbol(Array, Decl(lib.d.ts, 1000, 23), Decl(lib.d.ts, 1171, 11))
+
diff --git a/tests/baselines/reference/classExtendingBuiltinType.types b/tests/baselines/reference/classExtendingBuiltinType.types
new file mode 100644
index 00000000000..ce774c0bff0
--- /dev/null
+++ b/tests/baselines/reference/classExtendingBuiltinType.types
@@ -0,0 +1,41 @@
+=== tests/cases/conformance/classes/classDeclarations/classExtendingBuiltinType.ts ===
+class C1 extends Object { }
+>C1 : C1
+>Object : ObjectConstructor
+
+class C2 extends Function { }
+>C2 : C2
+>Function : FunctionConstructor
+
+class C3 extends String { }
+>C3 : C3
+>String : StringConstructor
+
+class C4 extends Boolean { }
+>C4 : C4
+>Boolean : BooleanConstructor
+
+class C5 extends Number { }
+>C5 : C5
+>Number : NumberConstructor
+
+class C6 extends Date { }
+>C6 : C6
+>Date : DateConstructor
+
+class C7 extends RegExp { }
+>C7 : C7
+>RegExp : RegExpConstructor
+
+class C8 extends Error { }
+>C8 : C8
+>Error : ErrorConstructor
+
+class C9 extends Array { }
+>C9 : C9
+>Array : ArrayConstructor
+
+class C10 extends Array<number> { }
+>C10 : C10
+>Array : ArrayConstructor
+
diff --git a/tests/baselines/reference/classExtendingClassLikeType.errors.txt b/tests/baselines/reference/classExtendingClassLikeType.errors.txt
new file mode 100644
index 00000000000..6f9aef927ea
--- /dev/null
+++ b/tests/baselines/reference/classExtendingClassLikeType.errors.txt
@@ -0,0 +1,70 @@
+tests/cases/conformance/classes/classDeclarations/classExtendingClassLikeType.ts(7,18): error TS2304: Cannot find name 'Base'.
+tests/cases/conformance/classes/classDeclarations/classExtendingClassLikeType.ts(45,18): error TS2508: No base constructor has the specified number of type arguments.
+tests/cases/conformance/classes/classDeclarations/classExtendingClassLikeType.ts(56,18): error TS2510: Base constructors must all have the same return type.
+
+
+==== tests/cases/conformance/classes/classDeclarations/classExtendingClassLikeType.ts (3 errors) ====
+    interface Base<T, U> {
+        x: T;
+        y: U;
+    }
+    
+    // Error, no Base constructor function
+    class D0 extends Base<string, string> {
+                     ~~~~
+!!! error TS2304: Cannot find name 'Base'.
+    }
+    
+    interface BaseConstructor {
+        new (x: string, y: string): Base<string, string>;
+        new <T>(x: T): Base<T, T>;
+        new <T>(x: T, y: T): Base<T, T>;
+        new <T, U>(x: T, y: U): Base<T, U>;
+    }
+    
+    declare function getBase(): BaseConstructor;
+    
+    class D1 extends getBase() {
+        constructor() {
+            super("abc", "def");
+            this.x = "x";
+            this.y = "y";
+        }
+    }
+    
+    class D2 extends getBase() <number> {
+        constructor() {
+            super(10);
+            super(10, 20);
+            this.x = 1;
+            this.y = 2;
+        }
+    }
+    
+    class D3 extends getBase() <string, number> {
+        constructor() {
+            super("abc", 42);
+            this.x = "x";
+            this.y = 2;
+        }
+    }
+    
+    // Error, no constructors with three type arguments
+    class D4 extends getBase() <string, string, string> {
+                     ~~~~~~~~~
+!!! error TS2508: No base constructor has the specified number of type arguments.
+    }
+    
+    interface BadBaseConstructor {
+        new (x: string): Base<string, string>;
+        new (x: number): Base<number, number>;
+    }
+    
+    declare function getBadBase(): BadBaseConstructor;
+    
+    // Error, constructor return types differ
+    class D5 extends getBadBase() {
+                     ~~~~~~~~~~~~
+!!! error TS2510: Base constructors must all have the same return type.
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendingClassLikeType.js b/tests/baselines/reference/classExtendingClassLikeType.js
new file mode 100644
index 00000000000..88a5dc8dcd3
--- /dev/null
+++ b/tests/baselines/reference/classExtendingClassLikeType.js
@@ -0,0 +1,119 @@
+//// [classExtendingClassLikeType.ts]
+interface Base<T, U> {
+    x: T;
+    y: U;
+}
+
+// Error, no Base constructor function
+class D0 extends Base<string, string> {
+}
+
+interface BaseConstructor {
+    new (x: string, y: string): Base<string, string>;
+    new <T>(x: T): Base<T, T>;
+    new <T>(x: T, y: T): Base<T, T>;
+    new <T, U>(x: T, y: U): Base<T, U>;
+}
+
+declare function getBase(): BaseConstructor;
+
+class D1 extends getBase() {
+    constructor() {
+        super("abc", "def");
+        this.x = "x";
+        this.y = "y";
+    }
+}
+
+class D2 extends getBase() <number> {
+    constructor() {
+        super(10);
+        super(10, 20);
+        this.x = 1;
+        this.y = 2;
+    }
+}
+
+class D3 extends getBase() <string, number> {
+    constructor() {
+        super("abc", 42);
+        this.x = "x";
+        this.y = 2;
+    }
+}
+
+// Error, no constructors with three type arguments
+class D4 extends getBase() <string, string, string> {
+}
+
+interface BadBaseConstructor {
+    new (x: string): Base<string, string>;
+    new (x: number): Base<number, number>;
+}
+
+declare function getBadBase(): BadBaseConstructor;
+
+// Error, constructor return types differ
+class D5 extends getBadBase() {
+}
+
+
+//// [classExtendingClassLikeType.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    __.prototype = b.prototype;
+    d.prototype = new __();
+};
+// Error, no Base constructor function
+var D0 = (function (_super) {
+    __extends(D0, _super);
+    function D0() {
+        _super.apply(this, arguments);
+    }
+    return D0;
+})(Base);
+var D1 = (function (_super) {
+    __extends(D1, _super);
+    function D1() {
+        _super.call(this, "abc", "def");
+        this.x = "x";
+        this.y = "y";
+    }
+    return D1;
+})(getBase());
+var D2 = (function (_super) {
+    __extends(D2, _super);
+    function D2() {
+        _super.call(this, 10);
+        _super.call(this, 10, 20);
+        this.x = 1;
+        this.y = 2;
+    }
+    return D2;
+})(getBase());
+var D3 = (function (_super) {
+    __extends(D3, _super);
+    function D3() {
+        _super.call(this, "abc", 42);
+        this.x = "x";
+        this.y = 2;
+    }
+    return D3;
+})(getBase());
+// Error, no constructors with three type arguments
+var D4 = (function (_super) {
+    __extends(D4, _super);
+    function D4() {
+        _super.apply(this, arguments);
+    }
+    return D4;
+})(getBase());
+// Error, constructor return types differ
+var D5 = (function (_super) {
+    __extends(D5, _super);
+    function D5() {
+        _super.apply(this, arguments);
+    }
+    return D5;
+})(getBadBase());
diff --git a/tests/baselines/reference/classExtendingNonConstructor.errors.txt b/tests/baselines/reference/classExtendingNonConstructor.errors.txt
new file mode 100644
index 00000000000..b1e3994cf1c
--- /dev/null
+++ b/tests/baselines/reference/classExtendingNonConstructor.errors.txt
@@ -0,0 +1,38 @@
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(7,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(8,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(9,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(10,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(11,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(12,18): error TS2507: Base expression is not of a constructor function type.
+tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts(13,18): error TS2507: Base expression is not of a constructor function type.
+
+
+==== tests/cases/conformance/classes/classDeclarations/classExtendingNonConstructor.ts (7 errors) ====
+    var x: {};
+    
+    function foo() {
+        this.x = 1;
+    }
+    
+    class C1 extends undefined { }
+                     ~~~~~~~~~
+!!! error TS2507: Base expression is not of a constructor function type.
+    class C2 extends true { }
+                     ~~~~
+!!! error TS2507: Base expression is not of a constructor function type.
+    class C3 extends false { }
+                     ~~~~~
+!!! error TS2507: Base expression is not of a constructor function type.
+    class C4 extends 42 { }
+                     ~~
+!!! error TS2507: Base expression is not of a constructor function type.
+    class C5 extends "hello" { }
+                     ~~~~~~~
+!!! error TS2507: Base expression is not of a constructor function type.
+    class C6 extends x { }
+                     ~
+!!! error TS2507: Base expression is not of a constructor function type.
+    class C7 extends foo { }
+                     ~~~
+!!! error TS2507: Base expression is not of a constructor function type.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/classExtendingNonConstructor.js b/tests/baselines/reference/classExtendingNonConstructor.js
new file mode 100644
index 00000000000..f796b30ddd6
--- /dev/null
+++ b/tests/baselines/reference/classExtendingNonConstructor.js
@@ -0,0 +1,76 @@
+//// [classExtendingNonConstructor.ts]
+var x: {};
+
+function foo() {
+    this.x = 1;
+}
+
+class C1 extends undefined { }
+class C2 extends true { }
+class C3 extends false { }
+class C4 extends 42 { }
+class C5 extends "hello" { }
+class C6 extends x { }
+class C7 extends foo { }
+
+
+//// [classExtendingNonConstructor.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    __.prototype = b.prototype;
+    d.prototype = new __();
+};
+var x;
+function foo() {
+    this.x = 1;
+}
+var C1 = (function (_super) {
+    __extends(C1, _super);
+    function C1() {
+        _super.apply(this, arguments);
+    }
+    return C1;
+})(undefined);
+var C2 = (function (_super) {
+    __extends(C2, _super);
+    function C2() {
+        _super.apply(this, arguments);
+    }
+    return C2;
+})(true);
+var C3 = (function (_super) {
+    __extends(C3, _super);
+    function C3() {
+        _super.apply(this, arguments);
+    }
+    return C3;
+})(false);
+var C4 = (function (_super) {
+    __extends(C4, _super);
+    function C4() {
+        _super.apply(this, arguments);
+    }
+    return C4;
+})(42);
+var C5 = (function (_super) {
+    __extends(C5, _super);
+    function C5() {
+        _super.apply(this, arguments);
+    }
+    return C5;
+})("hello");
+var C6 = (function (_super) {
+    __extends(C6, _super);
+    function C6() {
+        _super.apply(this, arguments);
+    }
+    return C6;
+})(x);
+var C7 = (function (_super) {
+    __extends(C7, _super);
+    function C7() {
+        _super.apply(this, arguments);
+    }
+    return C7;
+})(foo);
diff --git a/tests/baselines/reference/classExtendingNull.js b/tests/baselines/reference/classExtendingNull.js
new file mode 100644
index 00000000000..f0c3ea69626
--- /dev/null
+++ b/tests/baselines/reference/classExtendingNull.js
@@ -0,0 +1,26 @@
+//// [classExtendingNull.ts]
+class C1 extends null { }
+class C2 extends (null) { }
+
+
+//// [classExtendingNull.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    __.prototype = b.prototype;
+    d.prototype = new __();
+};
+var C1 = (function (_super) {
+    __extends(C1, _super);
+    function C1() {
+        _super.apply(this, arguments);
+    }
+    return C1;
+})(null);
+var C2 = (function (_super) {
+    __extends(C2, _super);
+    function C2() {
+        _super.apply(this, arguments);
+    }
+    return C2;
+})((null));
diff --git a/tests/baselines/reference/classExtendingNull.symbols b/tests/baselines/reference/classExtendingNull.symbols
new file mode 100644
index 00000000000..37a6162f414
--- /dev/null
+++ b/tests/baselines/reference/classExtendingNull.symbols
@@ -0,0 +1,7 @@
+=== tests/cases/conformance/classes/classDeclarations/classExtendingNull.ts ===
+class C1 extends null { }
+>C1 : Symbol(C1, Decl(classExtendingNull.ts, 0, 0))
+
+class C2 extends (null) { }
+>C2 : Symbol(C2, Decl(classExtendingNull.ts, 0, 25))
+
diff --git a/tests/baselines/reference/classExtendingNull.types b/tests/baselines/reference/classExtendingNull.types
new file mode 100644
index 00000000000..3c572a3406c
--- /dev/null
+++ b/tests/baselines/reference/classExtendingNull.types
@@ -0,0 +1,10 @@
+=== tests/cases/conformance/classes/classDeclarations/classExtendingNull.ts ===
+class C1 extends null { }
+>C1 : C1
+>null : null
+
+class C2 extends (null) { }
+>C2 : C2
+>(null) : null
+>null : null
+