diff --git a/tests/baselines/reference/classConstructorAccessibility.errors.txt b/tests/baselines/reference/classConstructorAccessibility.errors.txt
index 783d8a3ea1c..c22f3593bc5 100644
--- a/tests/baselines/reference/classConstructorAccessibility.errors.txt
+++ b/tests/baselines/reference/classConstructorAccessibility.errors.txt
@@ -1,8 +1,10 @@
 tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(6,5): error TS1089: 'private' modifier cannot appear on a constructor declaration.
-tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(18,9): error TS1089: 'private' modifier cannot appear on a constructor declaration.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(10,5): error TS1089: 'protected' modifier cannot appear on a constructor declaration.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(23,9): error TS1089: 'private' modifier cannot appear on a constructor declaration.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(27,9): error TS1089: 'protected' modifier cannot appear on a constructor declaration.
 
 
-==== tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts (2 errors) ====
+==== tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts (4 errors) ====
     class C {
         public constructor(public x: number) { }
     }
@@ -13,8 +15,15 @@ tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessib
 !!! error TS1089: 'private' modifier cannot appear on a constructor declaration.
     }
     
+    class E {
+        protected constructor(public x: number) { } // error
+        ~~~~~~~~~
+!!! error TS1089: 'protected' modifier cannot appear on a constructor declaration.
+    }
+    
     var c = new C(1);
     var d = new D(1);
+    var e = new E(1);
     
     module Generic {
         class C<T> {
@@ -27,7 +36,14 @@ tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessib
 !!! error TS1089: 'private' modifier cannot appear on a constructor declaration.
         }
     
+        class E<T> {
+            protected constructor(public x: T) { } // error
+            ~~~~~~~~~
+!!! error TS1089: 'protected' modifier cannot appear on a constructor declaration.
+        }
+    
         var c = new C(1);
         var d = new D(1);
+        var e = new E(1);
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/classPropertyAsProtected.errors.txt b/tests/baselines/reference/classPropertyAsProtected.errors.txt
new file mode 100644
index 00000000000..570ebc718ac
--- /dev/null
+++ b/tests/baselines/reference/classPropertyAsProtected.errors.txt
@@ -0,0 +1,62 @@
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(3,19): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(4,19): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(8,26): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(9,26): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(15,1): error TS2445: Property 'x' is protected and only accessible within class 'C' and its subclasses.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(16,1): error TS2445: Property 'y' is protected and only accessible within class 'C' and its subclasses.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(17,1): error TS2445: Property 'y' is protected and only accessible within class 'C' and its subclasses.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(18,1): error TS2445: Property 'foo' is protected and only accessible within class 'C' and its subclasses.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(20,1): error TS2445: Property 'a' is protected and only accessible within class 'C' and its subclasses.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(21,1): error TS2445: Property 'b' is protected and only accessible within class 'C' and its subclasses.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(22,1): error TS2445: Property 'b' is protected and only accessible within class 'C' and its subclasses.
+tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts(23,1): error TS2445: Property 'foo' is protected and only accessible within class 'C' and its subclasses.
+
+
+==== tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts (12 errors) ====
+    class C {
+        protected x: string;
+        protected get y() { return null; }
+                      ~
+!!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+        protected set y(x) { }
+                      ~
+!!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+        protected foo() { }
+    
+        protected static a: string;
+        protected static get b() { return null; }
+                             ~
+!!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+        protected static set b(x) { }
+                             ~
+!!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+        protected static foo() { }
+    }
+    
+    var c: C;
+    // all errors
+    c.x;
+    ~~~
+!!! error TS2445: Property 'x' is protected and only accessible within class 'C' and its subclasses.
+    c.y;
+    ~~~
+!!! error TS2445: Property 'y' is protected and only accessible within class 'C' and its subclasses.
+    c.y = 1;
+    ~~~
+!!! error TS2445: Property 'y' is protected and only accessible within class 'C' and its subclasses.
+    c.foo();
+    ~~~~~
+!!! error TS2445: Property 'foo' is protected and only accessible within class 'C' and its subclasses.
+    
+    C.a;
+    ~~~
+!!! error TS2445: Property 'a' is protected and only accessible within class 'C' and its subclasses.
+    C.b();
+    ~~~
+!!! error TS2445: Property 'b' is protected and only accessible within class 'C' and its subclasses.
+    C.b = 1;
+    ~~~
+!!! error TS2445: Property 'b' is protected and only accessible within class 'C' and its subclasses.
+    C.foo();
+    ~~~~~
+!!! error TS2445: Property 'foo' is protected and only accessible within class 'C' and its subclasses.
\ No newline at end of file
diff --git a/tests/baselines/reference/constructorParameterProperties.errors.txt b/tests/baselines/reference/constructorParameterProperties.errors.txt
index 63018d57024..ab9bebe9d2d 100644
--- a/tests/baselines/reference/constructorParameterProperties.errors.txt
+++ b/tests/baselines/reference/constructorParameterProperties.errors.txt
@@ -1,12 +1,14 @@
 tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts(8,10): error TS2341: Property 'x' is private and only accessible within class 'C'.
-tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts(17,10): error TS2341: Property 'x' is private and only accessible within class 'D<T>'.
-tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts(18,12): error TS2339: Property 'a' does not exist on type 'D<string>'.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts(9,10): error TS2445: Property 'z' is protected and only accessible within class 'C' and its subclasses.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts(18,10): error TS2341: Property 'x' is private and only accessible within class 'D<T>'.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts(19,12): error TS2339: Property 'a' does not exist on type 'D<string>'.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts(20,10): error TS2445: Property 'z' is protected and only accessible within class 'D<T>' and its subclasses.
 
 
-==== tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts (3 errors) ====
+==== tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts (5 errors) ====
     class C {
         y: string;
-        constructor(private x: string) { }
+        constructor(private x: string, protected z: string) { }
     }
     
     var c: C;
@@ -14,10 +16,13 @@ tests/cases/conformance/classes/constructorDeclarations/constructorParameters/co
     var r2 = c.x; // error
              ~~~
 !!! error TS2341: Property 'x' is private and only accessible within class 'C'.
+    var r3 = c.z; // error
+             ~~~
+!!! error TS2445: Property 'z' is protected and only accessible within class 'C' and its subclasses.
     
     class D<T> {
         y: T;
-        constructor(a: T, private x: T) { }
+        constructor(a: T, private x: T, protected z: T) { }
     }
     
     var d: D<string>;
@@ -27,4 +32,8 @@ tests/cases/conformance/classes/constructorDeclarations/constructorParameters/co
 !!! error TS2341: Property 'x' is private and only accessible within class 'D<T>'.
     var r3 = d.a; // error
                ~
-!!! error TS2339: Property 'a' does not exist on type 'D<string>'.
\ No newline at end of file
+!!! error TS2339: Property 'a' does not exist on type 'D<string>'.
+    var r4 = d.z; // error
+             ~~~
+!!! error TS2445: Property 'z' is protected and only accessible within class 'D<T>' and its subclasses.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/constructorParameterProperties.js b/tests/baselines/reference/constructorParameterProperties.js
index 37ba30d24b0..11446a316d3 100644
--- a/tests/baselines/reference/constructorParameterProperties.js
+++ b/tests/baselines/reference/constructorParameterProperties.js
@@ -1,36 +1,42 @@
 //// [constructorParameterProperties.ts]
 class C {
     y: string;
-    constructor(private x: string) { }
+    constructor(private x: string, protected z: string) { }
 }
 
 var c: C;
 var r = c.y;
 var r2 = c.x; // error
+var r3 = c.z; // error
 
 class D<T> {
     y: T;
-    constructor(a: T, private x: T) { }
+    constructor(a: T, private x: T, protected z: T) { }
 }
 
 var d: D<string>;
 var r = d.y;
 var r2 = d.x; // error
-var r3 = d.a; // error
+var r3 = d.a; // error
+var r4 = d.z; // error
+
 
 //// [constructorParameterProperties.js]
 var C = (function () {
-    function C(x) {
+    function C(x, z) {
         this.x = x;
+        this.z = z;
     }
     return C;
 })();
 var c;
 var r = c.y;
 var r2 = c.x; // error
+var r3 = c.z; // error
 var D = (function () {
-    function D(a, x) {
+    function D(a, x, z) {
         this.x = x;
+        this.z = z;
     }
     return D;
 })();
@@ -38,3 +44,4 @@ var d;
 var r = d.y;
 var r2 = d.x; // error
 var r3 = d.a; // error
+var r4 = d.z; // error
diff --git a/tests/baselines/reference/constructorParameterProperties2.errors.txt b/tests/baselines/reference/constructorParameterProperties2.errors.txt
index e6535bbbd54..df759fbe709 100644
--- a/tests/baselines/reference/constructorParameterProperties2.errors.txt
+++ b/tests/baselines/reference/constructorParameterProperties2.errors.txt
@@ -1,8 +1,9 @@
 tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(11,24): error TS2300: Duplicate identifier 'y'.
 tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(19,25): error TS2300: Duplicate identifier 'y'.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(27,27): error TS2300: Duplicate identifier 'y'.
 
 
-==== tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts (2 errors) ====
+==== tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts (3 errors) ====
     class C {
         y: number;
         constructor(y: number) { } // ok
@@ -29,4 +30,15 @@ tests/cases/conformance/classes/constructorDeclarations/constructorParameters/co
     }
     
     var e: E;
-    var r3 = e.y; // error
\ No newline at end of file
+    var r3 = e.y; // error
+    
+    class F {
+        y: number;
+        constructor(protected y: number) { } // error
+                              ~
+!!! error TS2300: Duplicate identifier 'y'.
+    }
+    
+    var f: F;
+    var r4 = f.y; // error
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/constructorParameterProperties2.js b/tests/baselines/reference/constructorParameterProperties2.js
index 8ad0c8b6ea6..02e4cf82c84 100644
--- a/tests/baselines/reference/constructorParameterProperties2.js
+++ b/tests/baselines/reference/constructorParameterProperties2.js
@@ -21,7 +21,16 @@ class E {
 }
 
 var e: E;
-var r3 = e.y; // error
+var r3 = e.y; // error
+
+class F {
+    y: number;
+    constructor(protected y: number) { } // error
+}
+
+var f: F;
+var r4 = f.y; // error
+
 
 //// [constructorParameterProperties2.js]
 var C = (function () {
@@ -47,3 +56,11 @@ var E = (function () {
 })();
 var e;
 var r3 = e.y; // error
+var F = (function () {
+    function F(y) {
+        this.y = y;
+    } // error
+    return F;
+})();
+var f;
+var r4 = f.y; // error
diff --git a/tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.errors.txt b/tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.errors.txt
new file mode 100644
index 00000000000..fc7cbbed97a
--- /dev/null
+++ b/tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.errors.txt
@@ -0,0 +1,74 @@
+tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts(9,7): error TS2421: Class 'Bar' incorrectly implements interface 'I':
+  Property 'y' is missing in type 'Bar'.
+tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts(12,7): error TS2421: Class 'Bar2' incorrectly implements interface 'I':
+  Property 'x' is missing in type 'Bar2'.
+tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts(16,7): error TS2421: Class 'Bar3' incorrectly implements interface 'I':
+  Property 'x' is protected but type 'Bar3' is not a class derived from 'Foo'.
+tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts(21,7): error TS2421: Class 'Bar4' incorrectly implements interface 'I':
+  Property 'x' is protected but type 'Bar4' is not a class derived from 'Foo'.
+tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts(26,7): error TS2421: Class 'Bar5' incorrectly implements interface 'I':
+  Property 'y' is missing in type 'Bar5'.
+tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts(29,7): error TS2421: Class 'Bar6' incorrectly implements interface 'I':
+  Property 'y' is protected in type 'Bar6' but public in type 'I'.
+
+
+==== tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts (6 errors) ====
+    class Foo {
+        protected x: string;
+    }
+    
+    interface I extends Foo {
+        y: number;
+    }
+    
+    class Bar implements I { // error
+          ~~~
+!!! error TS2421: Class 'Bar' incorrectly implements interface 'I':
+!!! error TS2421:   Property 'y' is missing in type 'Bar'.
+    }
+    
+    class Bar2 implements I { // error
+          ~~~~
+!!! error TS2421: Class 'Bar2' incorrectly implements interface 'I':
+!!! error TS2421:   Property 'x' is missing in type 'Bar2'.
+        y: number;
+    }
+    
+    class Bar3 implements I { // error
+          ~~~~
+!!! error TS2421: Class 'Bar3' incorrectly implements interface 'I':
+!!! error TS2421:   Property 'x' is protected but type 'Bar3' is not a class derived from 'Foo'.
+        x: string;
+        y: number;
+    }
+    
+    class Bar4 implements I { // error
+          ~~~~
+!!! error TS2421: Class 'Bar4' incorrectly implements interface 'I':
+!!! error TS2421:   Property 'x' is protected but type 'Bar4' is not a class derived from 'Foo'.
+        protected x: string;
+        y: number;
+    }
+    
+    class Bar5 extends Foo implements I { // error
+          ~~~~
+!!! error TS2421: Class 'Bar5' incorrectly implements interface 'I':
+!!! error TS2421:   Property 'y' is missing in type 'Bar5'.
+    }
+    
+    class Bar6 extends Foo implements I { // error
+          ~~~~
+!!! error TS2421: Class 'Bar6' incorrectly implements interface 'I':
+!!! error TS2421:   Property 'y' is protected in type 'Bar6' but public in type 'I'.
+        protected y: number;
+    }
+    
+    class Bar7 extends Foo implements I {
+        y: number;
+    }
+    
+    class Bar8 extends Foo implements I {
+        x: string;
+        y: number;
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.js b/tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.js
new file mode 100644
index 00000000000..1a79496bd12
--- /dev/null
+++ b/tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.js
@@ -0,0 +1,103 @@
+//// [implementingAnInterfaceExtendingClassWithProtecteds.ts]
+class Foo {
+    protected x: string;
+}
+
+interface I extends Foo {
+    y: number;
+}
+
+class Bar implements I { // error
+}
+
+class Bar2 implements I { // error
+    y: number;
+}
+
+class Bar3 implements I { // error
+    x: string;
+    y: number;
+}
+
+class Bar4 implements I { // error
+    protected x: string;
+    y: number;
+}
+
+class Bar5 extends Foo implements I { // error
+}
+
+class Bar6 extends Foo implements I { // error
+    protected y: number;
+}
+
+class Bar7 extends Foo implements I {
+    y: number;
+}
+
+class Bar8 extends Foo implements I {
+    x: string;
+    y: number;
+}
+
+
+//// [implementingAnInterfaceExtendingClassWithProtecteds.js]
+var __extends = 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 Foo = (function () {
+    function Foo() {
+    }
+    return Foo;
+})();
+var Bar = (function () {
+    function Bar() {
+    }
+    return Bar;
+})();
+var Bar2 = (function () {
+    function Bar2() {
+    }
+    return Bar2;
+})();
+var Bar3 = (function () {
+    function Bar3() {
+    }
+    return Bar3;
+})();
+var Bar4 = (function () {
+    function Bar4() {
+    }
+    return Bar4;
+})();
+var Bar5 = (function (_super) {
+    __extends(Bar5, _super);
+    function Bar5() {
+        _super.apply(this, arguments);
+    }
+    return Bar5;
+})(Foo);
+var Bar6 = (function (_super) {
+    __extends(Bar6, _super);
+    function Bar6() {
+        _super.apply(this, arguments);
+    }
+    return Bar6;
+})(Foo);
+var Bar7 = (function (_super) {
+    __extends(Bar7, _super);
+    function Bar7() {
+        _super.apply(this, arguments);
+    }
+    return Bar7;
+})(Foo);
+var Bar8 = (function (_super) {
+    __extends(Bar8, _super);
+    function Bar8() {
+        _super.apply(this, arguments);
+    }
+    return Bar8;
+})(Foo);
diff --git a/tests/baselines/reference/interfaceExtendingClassWithProtecteds.errors.txt b/tests/baselines/reference/interfaceExtendingClassWithProtecteds.errors.txt
new file mode 100644
index 00000000000..1cbc921e1ac
--- /dev/null
+++ b/tests/baselines/reference/interfaceExtendingClassWithProtecteds.errors.txt
@@ -0,0 +1,26 @@
+tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds.ts(5,11): error TS2429: Interface 'I' incorrectly extends interface 'Foo':
+  Property 'x' is protected but type 'I' is not a class derived from 'Foo'.
+tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds.ts(15,10): error TS2445: Property 'x' is protected and only accessible within class 'Foo' and its subclasses.
+
+
+==== tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds.ts (2 errors) ====
+    class Foo {
+        protected x: string;
+    }
+    
+    interface I extends Foo { // error
+              ~
+!!! error TS2429: Interface 'I' incorrectly extends interface 'Foo':
+!!! error TS2429:   Property 'x' is protected but type 'I' is not a class derived from 'Foo'.
+        x: string;
+    }
+    
+    interface I2 extends Foo {
+        y: string;
+    }
+    
+    var i: I2;
+    var r = i.y;
+    var r2 = i.x; // error
+             ~~~
+!!! error TS2445: Property 'x' is protected and only accessible within class 'Foo' and its subclasses.
\ No newline at end of file
diff --git a/tests/baselines/reference/interfaceExtendingClassWithProtecteds.js b/tests/baselines/reference/interfaceExtendingClassWithProtecteds.js
new file mode 100644
index 00000000000..f2d95812fd2
--- /dev/null
+++ b/tests/baselines/reference/interfaceExtendingClassWithProtecteds.js
@@ -0,0 +1,26 @@
+//// [interfaceExtendingClassWithProtecteds.ts]
+class Foo {
+    protected x: string;
+}
+
+interface I extends Foo { // error
+    x: string;
+}
+
+interface I2 extends Foo {
+    y: string;
+}
+
+var i: I2;
+var r = i.y;
+var r2 = i.x; // error
+
+//// [interfaceExtendingClassWithProtecteds.js]
+var Foo = (function () {
+    function Foo() {
+    }
+    return Foo;
+})();
+var i;
+var r = i.y;
+var r2 = i.x; // error
diff --git a/tests/baselines/reference/interfaceExtendingClassWithProtecteds2.errors.txt b/tests/baselines/reference/interfaceExtendingClassWithProtecteds2.errors.txt
new file mode 100644
index 00000000000..4e5b6364010
--- /dev/null
+++ b/tests/baselines/reference/interfaceExtendingClassWithProtecteds2.errors.txt
@@ -0,0 +1,51 @@
+tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts(9,11): error TS2320: Interface 'I3' cannot simultaneously extend types 'Foo' and 'Bar':
+  Named properties 'x' of types 'Foo' and 'Bar' are not identical.
+tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts(12,11): error TS2429: Interface 'I4' incorrectly extends interface 'Bar':
+  Property 'x' is protected but type 'I4' is not a class derived from 'Bar'.
+tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts(12,11): error TS2429: Interface 'I4' incorrectly extends interface 'Foo':
+  Property 'x' is protected but type 'I4' is not a class derived from 'Foo'.
+tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts(26,10): error TS2445: Property 'x' is protected and only accessible within class 'Foo' and its subclasses.
+tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts(27,10): error TS2445: Property 'y' is protected and only accessible within class 'Baz' and its subclasses.
+
+
+==== tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts (5 errors) ====
+    class Foo {
+        protected x: string;
+    }
+    
+    class Bar {
+        protected x: string;
+    }
+    
+    interface I3 extends Foo, Bar { // error
+              ~~
+!!! error TS2320: Interface 'I3' cannot simultaneously extend types 'Foo' and 'Bar':
+!!! error TS2320:   Named properties 'x' of types 'Foo' and 'Bar' are not identical.
+    }
+    
+    interface I4 extends Foo, Bar { // error
+              ~~
+!!! error TS2429: Interface 'I4' incorrectly extends interface 'Bar':
+!!! error TS2429:   Property 'x' is protected but type 'I4' is not a class derived from 'Bar'.
+              ~~
+!!! error TS2429: Interface 'I4' incorrectly extends interface 'Foo':
+!!! error TS2429:   Property 'x' is protected but type 'I4' is not a class derived from 'Foo'.
+        x: string;
+    }
+    
+    class Baz {
+        protected y: string;
+    }
+    
+    interface I5 extends Foo, Baz {
+        z: string;
+    }
+    
+    var i: I5;
+    var r: string = i.z;
+    var r2 = i.x; // error
+             ~~~
+!!! error TS2445: Property 'x' is protected and only accessible within class 'Foo' and its subclasses.
+    var r3 = i.y; // error
+             ~~~
+!!! error TS2445: Property 'y' is protected and only accessible within class 'Baz' and its subclasses.
\ No newline at end of file
diff --git a/tests/baselines/reference/interfaceExtendingClassWithProtecteds2.js b/tests/baselines/reference/interfaceExtendingClassWithProtecteds2.js
new file mode 100644
index 00000000000..277c32a10c1
--- /dev/null
+++ b/tests/baselines/reference/interfaceExtendingClassWithProtecteds2.js
@@ -0,0 +1,49 @@
+//// [interfaceExtendingClassWithProtecteds2.ts]
+class Foo {
+    protected x: string;
+}
+
+class Bar {
+    protected x: string;
+}
+
+interface I3 extends Foo, Bar { // error
+}
+
+interface I4 extends Foo, Bar { // error
+    x: string;
+}
+
+class Baz {
+    protected y: string;
+}
+
+interface I5 extends Foo, Baz {
+    z: string;
+}
+
+var i: I5;
+var r: string = i.z;
+var r2 = i.x; // error
+var r3 = i.y; // error
+
+//// [interfaceExtendingClassWithProtecteds2.js]
+var Foo = (function () {
+    function Foo() {
+    }
+    return Foo;
+})();
+var Bar = (function () {
+    function Bar() {
+    }
+    return Bar;
+})();
+var Baz = (function () {
+    function Baz() {
+    }
+    return Baz;
+})();
+var i;
+var r = i.z;
+var r2 = i.x; // error
+var r3 = i.y; // error
diff --git a/tests/baselines/reference/protectedClassPropertyAccessibleWithinClass.js b/tests/baselines/reference/protectedClassPropertyAccessibleWithinClass.js
new file mode 100644
index 00000000000..992011ee4af
--- /dev/null
+++ b/tests/baselines/reference/protectedClassPropertyAccessibleWithinClass.js
@@ -0,0 +1,117 @@
+//// [protectedClassPropertyAccessibleWithinClass.ts]
+// no errors
+
+class C {
+    protected x: string;
+    protected get y() { return this.x; }
+    protected set y(x) { this.y = this.x; }
+    protected foo() { return this.foo; }
+
+    protected static x: string;
+    protected static get y() { return this.x; }
+    protected static set y(x) { this.y = this.x; }
+    protected static foo() { return this.foo; }
+    protected static bar() { this.foo(); }
+}
+
+// added level of function nesting
+class C2 {
+    protected x: string;
+    protected get y() { () => this.x; return null; }
+    protected set y(x) { () => { this.y = this.x; } }
+    protected foo() { () => this.foo; }
+
+    protected static x: string;
+    protected static get y() { () => this.x; return null; }
+    protected static set y(x) {
+        () => { this.y = this.x; }
+     }
+    protected static foo() { () => this.foo; }
+    protected static bar() { () => this.foo(); }
+}
+
+
+//// [protectedClassPropertyAccessibleWithinClass.js]
+// no errors
+var C = (function () {
+    function C() {
+    }
+    Object.defineProperty(C.prototype, "y", {
+        get: function () {
+            return this.x;
+        },
+        set: function (x) {
+            this.y = this.x;
+        },
+        enumerable: true,
+        configurable: true
+    });
+    C.prototype.foo = function () {
+        return this.foo;
+    };
+    Object.defineProperty(C, "y", {
+        get: function () {
+            return this.x;
+        },
+        set: function (x) {
+            this.y = this.x;
+        },
+        enumerable: true,
+        configurable: true
+    });
+    C.foo = function () {
+        return this.foo;
+    };
+    C.bar = function () {
+        this.foo();
+    };
+    return C;
+})();
+// added level of function nesting
+var C2 = (function () {
+    function C2() {
+    }
+    Object.defineProperty(C2.prototype, "y", {
+        get: function () {
+            var _this = this;
+            (function () { return _this.x; });
+            return null;
+        },
+        set: function (x) {
+            var _this = this;
+            (function () {
+                _this.y = _this.x;
+            });
+        },
+        enumerable: true,
+        configurable: true
+    });
+    C2.prototype.foo = function () {
+        var _this = this;
+        (function () { return _this.foo; });
+    };
+    Object.defineProperty(C2, "y", {
+        get: function () {
+            var _this = this;
+            (function () { return _this.x; });
+            return null;
+        },
+        set: function (x) {
+            var _this = this;
+            (function () {
+                _this.y = _this.x;
+            });
+        },
+        enumerable: true,
+        configurable: true
+    });
+    C2.foo = function () {
+        var _this = this;
+        (function () { return _this.foo; });
+    };
+    C2.bar = function () {
+        var _this = this;
+        (function () { return _this.foo(); });
+    };
+    return C2;
+})();
diff --git a/tests/baselines/reference/protectedClassPropertyAccessibleWithinClass.types b/tests/baselines/reference/protectedClassPropertyAccessibleWithinClass.types
new file mode 100644
index 00000000000..241b3cfc7a1
--- /dev/null
+++ b/tests/baselines/reference/protectedClassPropertyAccessibleWithinClass.types
@@ -0,0 +1,139 @@
+=== tests/cases/conformance/classes/members/accessibility/protectedClassPropertyAccessibleWithinClass.ts ===
+// no errors
+
+class C {
+>C : C
+
+    protected x: string;
+>x : string
+
+    protected get y() { return this.x; }
+>y : string
+>this.x : string
+>this : C
+>x : string
+
+    protected set y(x) { this.y = this.x; }
+>y : string
+>x : string
+>this.y = this.x : string
+>this.y : string
+>this : C
+>y : string
+>this.x : string
+>this : C
+>x : string
+
+    protected foo() { return this.foo; }
+>foo : () => any
+>this.foo : () => any
+>this : C
+>foo : () => any
+
+    protected static x: string;
+>x : string
+
+    protected static get y() { return this.x; }
+>y : string
+>this.x : string
+>this : typeof C
+>x : string
+
+    protected static set y(x) { this.y = this.x; }
+>y : string
+>x : string
+>this.y = this.x : string
+>this.y : string
+>this : typeof C
+>y : string
+>this.x : string
+>this : typeof C
+>x : string
+
+    protected static foo() { return this.foo; }
+>foo : () => typeof C.foo
+>this.foo : () => typeof C.foo
+>this : typeof C
+>foo : () => typeof C.foo
+
+    protected static bar() { this.foo(); }
+>bar : () => void
+>this.foo() : () => typeof C.foo
+>this.foo : () => typeof C.foo
+>this : typeof C
+>foo : () => typeof C.foo
+}
+
+// added level of function nesting
+class C2 {
+>C2 : C2
+
+    protected x: string;
+>x : string
+
+    protected get y() { () => this.x; return null; }
+>y : any
+>() => this.x : () => string
+>this.x : string
+>this : C2
+>x : string
+
+    protected set y(x) { () => { this.y = this.x; } }
+>y : any
+>x : any
+>() => { this.y = this.x; } : () => void
+>this.y = this.x : string
+>this.y : any
+>this : C2
+>y : any
+>this.x : string
+>this : C2
+>x : string
+
+    protected foo() { () => this.foo; }
+>foo : () => void
+>() => this.foo : () => () => void
+>this.foo : () => void
+>this : C2
+>foo : () => void
+
+    protected static x: string;
+>x : string
+
+    protected static get y() { () => this.x; return null; }
+>y : any
+>() => this.x : () => string
+>this.x : string
+>this : typeof C2
+>x : string
+
+    protected static set y(x) {
+>y : any
+>x : any
+
+        () => { this.y = this.x; }
+>() => { this.y = this.x; } : () => void
+>this.y = this.x : string
+>this.y : any
+>this : typeof C2
+>y : any
+>this.x : string
+>this : typeof C2
+>x : string
+     }
+    protected static foo() { () => this.foo; }
+>foo : () => void
+>() => this.foo : () => () => void
+>this.foo : () => void
+>this : typeof C2
+>foo : () => void
+
+    protected static bar() { () => this.foo(); }
+>bar : () => void
+>() => this.foo() : () => void
+>this.foo() : void
+>this.foo : () => void
+>this : typeof C2
+>foo : () => void
+}
+
diff --git a/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass.js b/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass.js
new file mode 100644
index 00000000000..381d10f43ea
--- /dev/null
+++ b/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass.js
@@ -0,0 +1,73 @@
+//// [protectedClassPropertyAccessibleWithinSubclass.ts]
+// no errors
+
+class B {
+    protected x: string;
+    protected static x: string;
+}
+
+class C extends B {
+    protected get y() { return this.x; }
+    protected set y(x) { this.y = this.x; }
+    protected foo() { return this.x; }
+    protected bar() { return this.foo(); }
+
+    protected static get y() { return this.x; }
+    protected static set y(x) { this.y = this.x; }
+    protected static foo() { return this.x; }
+    protected static bar() { this.foo(); }
+}
+
+
+//// [protectedClassPropertyAccessibleWithinSubclass.js]
+// no errors
+var __extends = 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 B = (function () {
+    function B() {
+    }
+    return B;
+})();
+var C = (function (_super) {
+    __extends(C, _super);
+    function C() {
+        _super.apply(this, arguments);
+    }
+    Object.defineProperty(C.prototype, "y", {
+        get: function () {
+            return this.x;
+        },
+        set: function (x) {
+            this.y = this.x;
+        },
+        enumerable: true,
+        configurable: true
+    });
+    C.prototype.foo = function () {
+        return this.x;
+    };
+    C.prototype.bar = function () {
+        return this.foo();
+    };
+    Object.defineProperty(C, "y", {
+        get: function () {
+            return this.x;
+        },
+        set: function (x) {
+            this.y = this.x;
+        },
+        enumerable: true,
+        configurable: true
+    });
+    C.foo = function () {
+        return this.x;
+    };
+    C.bar = function () {
+        this.foo();
+    };
+    return C;
+})(B);
diff --git a/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass.types b/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass.types
new file mode 100644
index 00000000000..bd230239d47
--- /dev/null
+++ b/tests/baselines/reference/protectedClassPropertyAccessibleWithinSubclass.types
@@ -0,0 +1,78 @@
+=== tests/cases/conformance/classes/members/accessibility/protectedClassPropertyAccessibleWithinSubclass.ts ===
+// no errors
+
+class B {
+>B : B
+
+    protected x: string;
+>x : string
+
+    protected static x: string;
+>x : string
+}
+
+class C extends B {
+>C : C
+>B : B
+
+    protected get y() { return this.x; }
+>y : string
+>this.x : string
+>this : C
+>x : string
+
+    protected set y(x) { this.y = this.x; }
+>y : string
+>x : string
+>this.y = this.x : string
+>this.y : string
+>this : C
+>y : string
+>this.x : string
+>this : C
+>x : string
+
+    protected foo() { return this.x; }
+>foo : () => string
+>this.x : string
+>this : C
+>x : string
+
+    protected bar() { return this.foo(); }
+>bar : () => string
+>this.foo() : string
+>this.foo : () => string
+>this : C
+>foo : () => string
+
+    protected static get y() { return this.x; }
+>y : string
+>this.x : string
+>this : typeof C
+>x : string
+
+    protected static set y(x) { this.y = this.x; }
+>y : string
+>x : string
+>this.y = this.x : string
+>this.y : string
+>this : typeof C
+>y : string
+>this.x : string
+>this : typeof C
+>x : string
+
+    protected static foo() { return this.x; }
+>foo : () => string
+>this.x : string
+>this : typeof C
+>x : string
+
+    protected static bar() { this.foo(); }
+>bar : () => void
+>this.foo() : string
+>this.foo : () => string
+>this : typeof C
+>foo : () => string
+}
+
diff --git a/tests/baselines/reference/protectedInstanceMemberAccessibility.errors.txt b/tests/baselines/reference/protectedInstanceMemberAccessibility.errors.txt
new file mode 100644
index 00000000000..03671925feb
--- /dev/null
+++ b/tests/baselines/reference/protectedInstanceMemberAccessibility.errors.txt
@@ -0,0 +1,86 @@
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(14,23): error TS2339: Property 'z' does not exist on type 'B'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(16,24): error TS2340: Only public and protected methods of the base class are accessible via the 'super' keyword
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(18,24): error TS2339: Property 'y' does not exist on type 'A'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(19,24): error TS2339: Property 'z' does not exist on type 'A'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(22,18): error TS2446: Property 'x' is protected and only accessible through an instance of class 'B'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(23,18): error TS2446: Property 'f' is protected and only accessible through an instance of class 'B'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(24,20): error TS2339: Property 'y' does not exist on type 'A'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(25,20): error TS2339: Property 'z' does not exist on type 'A'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(31,20): error TS2339: Property 'z' does not exist on type 'B'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(34,18): error TS2446: Property 'x' is protected and only accessible through an instance of class 'B'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(35,18): error TS2446: Property 'f' is protected and only accessible through an instance of class 'B'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(36,20): error TS2339: Property 'y' does not exist on type 'C'.
+tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts(37,18): error TS2445: Property 'z' is protected and only accessible within class 'C' and its subclasses.
+
+
+==== tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts (13 errors) ====
+    class A {
+        protected x: string;
+        protected f(): string {
+            return "hello";
+        }
+    }
+    
+    class B extends A {
+        protected y: string;
+        g() {
+            var t1 = this.x;
+            var t2 = this.f();
+            var t3 = this.y;
+            var t4 = this.z;     // error
+                          ~
+!!! error TS2339: Property 'z' does not exist on type 'B'.
+    
+            var s1 = super.x;    // error
+                           ~
+!!! error TS2340: Only public and protected methods of the base class are accessible via the 'super' keyword
+            var s2 = super.f();
+            var s3 = super.y;    // error
+                           ~
+!!! error TS2339: Property 'y' does not exist on type 'A'.
+            var s4 = super.z;    // error
+                           ~
+!!! error TS2339: Property 'z' does not exist on type 'A'.
+    
+            var a: A;
+            var a1 = a.x;    // error
+                     ~~~
+!!! error TS2446: Property 'x' is protected and only accessible through an instance of class 'B'.
+            var a2 = a.f();  // error
+                     ~~~
+!!! error TS2446: Property 'f' is protected and only accessible through an instance of class 'B'.
+            var a3 = a.y;    // error
+                       ~
+!!! error TS2339: Property 'y' does not exist on type 'A'.
+            var a4 = a.z;    // error
+                       ~
+!!! error TS2339: Property 'z' does not exist on type 'A'.
+    
+            var b: B;
+            var b1 = b.x;
+            var b2 = b.f();
+            var b3 = b.y;
+            var b4 = b.z;    // error
+                       ~
+!!! error TS2339: Property 'z' does not exist on type 'B'.
+    
+            var c: C;
+            var c1 = c.x;    // error
+                     ~~~
+!!! error TS2446: Property 'x' is protected and only accessible through an instance of class 'B'.
+            var c2 = c.f();  // error
+                     ~~~
+!!! error TS2446: Property 'f' is protected and only accessible through an instance of class 'B'.
+            var c3 = c.y;    // error
+                       ~
+!!! error TS2339: Property 'y' does not exist on type 'C'.
+            var c4 = c.z;    // error
+                     ~~~
+!!! error TS2445: Property 'z' is protected and only accessible within class 'C' and its subclasses.
+        }
+    }
+    
+    class C extends A {
+        protected z: string;
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/protectedInstanceMemberAccessibility.js b/tests/baselines/reference/protectedInstanceMemberAccessibility.js
new file mode 100644
index 00000000000..de7a6e0d00e
--- /dev/null
+++ b/tests/baselines/reference/protectedInstanceMemberAccessibility.js
@@ -0,0 +1,100 @@
+//// [protectedInstanceMemberAccessibility.ts]
+class A {
+    protected x: string;
+    protected f(): string {
+        return "hello";
+    }
+}
+
+class B extends A {
+    protected y: string;
+    g() {
+        var t1 = this.x;
+        var t2 = this.f();
+        var t3 = this.y;
+        var t4 = this.z;     // error
+
+        var s1 = super.x;    // error
+        var s2 = super.f();
+        var s3 = super.y;    // error
+        var s4 = super.z;    // error
+
+        var a: A;
+        var a1 = a.x;    // error
+        var a2 = a.f();  // error
+        var a3 = a.y;    // error
+        var a4 = a.z;    // error
+
+        var b: B;
+        var b1 = b.x;
+        var b2 = b.f();
+        var b3 = b.y;
+        var b4 = b.z;    // error
+
+        var c: C;
+        var c1 = c.x;    // error
+        var c2 = c.f();  // error
+        var c3 = c.y;    // error
+        var c4 = c.z;    // error
+    }
+}
+
+class C extends A {
+    protected z: string;
+}
+
+
+//// [protectedInstanceMemberAccessibility.js]
+var __extends = 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 A = (function () {
+    function A() {
+    }
+    A.prototype.f = function () {
+        return "hello";
+    };
+    return A;
+})();
+var B = (function (_super) {
+    __extends(B, _super);
+    function B() {
+        _super.apply(this, arguments);
+    }
+    B.prototype.g = function () {
+        var t1 = this.x;
+        var t2 = this.f();
+        var t3 = this.y;
+        var t4 = this.z; // error
+        var s1 = _super.prototype.x; // error
+        var s2 = _super.prototype.f.call(this);
+        var s3 = _super.prototype.y; // error
+        var s4 = _super.prototype.z; // error
+        var a;
+        var a1 = a.x; // error
+        var a2 = a.f(); // error
+        var a3 = a.y; // error
+        var a4 = a.z; // error
+        var b;
+        var b1 = b.x;
+        var b2 = b.f();
+        var b3 = b.y;
+        var b4 = b.z; // error
+        var c;
+        var c1 = c.x; // error
+        var c2 = c.f(); // error
+        var c3 = c.y; // error
+        var c4 = c.z; // error
+    };
+    return B;
+})(A);
+var C = (function (_super) {
+    __extends(C, _super);
+    function C() {
+        _super.apply(this, arguments);
+    }
+    return C;
+})(A);
diff --git a/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts b/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts
index 353ab012234..c2e4855e63a 100644
--- a/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts
+++ b/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts
@@ -6,8 +6,13 @@ class D {
     private constructor(public x: number) { } // error
 }
 
+class E {
+    protected constructor(public x: number) { } // error
+}
+
 var c = new C(1);
 var d = new D(1);
+var e = new E(1);
 
 module Generic {
     class C<T> {
@@ -18,6 +23,11 @@ module Generic {
         private constructor(public x: T) { } // error
     }
 
+    class E<T> {
+        protected constructor(public x: T) { } // error
+    }
+
     var c = new C(1);
     var d = new D(1);
+    var e = new E(1);
 }
diff --git a/tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts b/tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts
index e3ea627f0c3..f4d63da1192 100644
--- a/tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts
+++ b/tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties.ts
@@ -1,18 +1,20 @@
 class C {
     y: string;
-    constructor(private x: string) { }
+    constructor(private x: string, protected z: string) { }
 }
 
 var c: C;
 var r = c.y;
 var r2 = c.x; // error
+var r3 = c.z; // error
 
 class D<T> {
     y: T;
-    constructor(a: T, private x: T) { }
+    constructor(a: T, private x: T, protected z: T) { }
 }
 
 var d: D<string>;
 var r = d.y;
 var r2 = d.x; // error
-var r3 = d.a; // error
\ No newline at end of file
+var r3 = d.a; // error
+var r4 = d.z; // error
diff --git a/tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts b/tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts
index 4d14e4bafbd..b95891c0845 100644
--- a/tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts
+++ b/tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts
@@ -20,4 +20,12 @@ class E {
 }
 
 var e: E;
-var r3 = e.y; // error
\ No newline at end of file
+var r3 = e.y; // error
+
+class F {
+    y: number;
+    constructor(protected y: number) { } // error
+}
+
+var f: F;
+var r4 = f.y; // error
diff --git a/tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts b/tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts
new file mode 100644
index 00000000000..7efe159c058
--- /dev/null
+++ b/tests/cases/conformance/classes/members/accessibility/classPropertyAsProtected.ts
@@ -0,0 +1,23 @@
+class C {
+    protected x: string;
+    protected get y() { return null; }
+    protected set y(x) { }
+    protected foo() { }
+
+    protected static a: string;
+    protected static get b() { return null; }
+    protected static set b(x) { }
+    protected static foo() { }
+}
+
+var c: C;
+// all errors
+c.x;
+c.y;
+c.y = 1;
+c.foo();
+
+C.a;
+C.b();
+C.b = 1;
+C.foo();
\ No newline at end of file
diff --git a/tests/cases/conformance/classes/members/accessibility/protectedClassPropertyAccessibleWithinClass.ts b/tests/cases/conformance/classes/members/accessibility/protectedClassPropertyAccessibleWithinClass.ts
new file mode 100644
index 00000000000..08f99af5972
--- /dev/null
+++ b/tests/cases/conformance/classes/members/accessibility/protectedClassPropertyAccessibleWithinClass.ts
@@ -0,0 +1,31 @@
+// @target: ES5
+// no errors
+
+class C {
+    protected x: string;
+    protected get y() { return this.x; }
+    protected set y(x) { this.y = this.x; }
+    protected foo() { return this.foo; }
+
+    protected static x: string;
+    protected static get y() { return this.x; }
+    protected static set y(x) { this.y = this.x; }
+    protected static foo() { return this.foo; }
+    protected static bar() { this.foo(); }
+}
+
+// added level of function nesting
+class C2 {
+    protected x: string;
+    protected get y() { () => this.x; return null; }
+    protected set y(x) { () => { this.y = this.x; } }
+    protected foo() { () => this.foo; }
+
+    protected static x: string;
+    protected static get y() { () => this.x; return null; }
+    protected static set y(x) {
+        () => { this.y = this.x; }
+     }
+    protected static foo() { () => this.foo; }
+    protected static bar() { () => this.foo(); }
+}
diff --git a/tests/cases/conformance/classes/members/accessibility/protectedClassPropertyAccessibleWithinSubclass.ts b/tests/cases/conformance/classes/members/accessibility/protectedClassPropertyAccessibleWithinSubclass.ts
new file mode 100644
index 00000000000..56c591f41ce
--- /dev/null
+++ b/tests/cases/conformance/classes/members/accessibility/protectedClassPropertyAccessibleWithinSubclass.ts
@@ -0,0 +1,19 @@
+// @target: ES5
+// no errors
+
+class B {
+    protected x: string;
+    protected static x: string;
+}
+
+class C extends B {
+    protected get y() { return this.x; }
+    protected set y(x) { this.y = this.x; }
+    protected foo() { return this.x; }
+    protected bar() { return this.foo(); }
+
+    protected static get y() { return this.x; }
+    protected static set y(x) { this.y = this.x; }
+    protected static foo() { return this.x; }
+    protected static bar() { this.foo(); }
+}
diff --git a/tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts b/tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts
new file mode 100644
index 00000000000..b92d29d4d63
--- /dev/null
+++ b/tests/cases/conformance/classes/members/accessibility/protectedInstanceMemberAccessibility.ts
@@ -0,0 +1,43 @@
+class A {
+    protected x: string;
+    protected f(): string {
+        return "hello";
+    }
+}
+
+class B extends A {
+    protected y: string;
+    g() {
+        var t1 = this.x;
+        var t2 = this.f();
+        var t3 = this.y;
+        var t4 = this.z;     // error
+
+        var s1 = super.x;    // error
+        var s2 = super.f();
+        var s3 = super.y;    // error
+        var s4 = super.z;    // error
+
+        var a: A;
+        var a1 = a.x;    // error
+        var a2 = a.f();  // error
+        var a3 = a.y;    // error
+        var a4 = a.z;    // error
+
+        var b: B;
+        var b1 = b.x;
+        var b2 = b.f();
+        var b3 = b.y;
+        var b4 = b.z;    // error
+
+        var c: C;
+        var c1 = c.x;    // error
+        var c2 = c.f();  // error
+        var c3 = c.y;    // error
+        var c4 = c.z;    // error
+    }
+}
+
+class C extends A {
+    protected z: string;
+}
diff --git a/tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts b/tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts
new file mode 100644
index 00000000000..746ab5bc393
--- /dev/null
+++ b/tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts
@@ -0,0 +1,40 @@
+class Foo {
+    protected x: string;
+}
+
+interface I extends Foo {
+    y: number;
+}
+
+class Bar implements I { // error
+}
+
+class Bar2 implements I { // error
+    y: number;
+}
+
+class Bar3 implements I { // error
+    x: string;
+    y: number;
+}
+
+class Bar4 implements I { // error
+    protected x: string;
+    y: number;
+}
+
+class Bar5 extends Foo implements I { // error
+}
+
+class Bar6 extends Foo implements I { // error
+    protected y: number;
+}
+
+class Bar7 extends Foo implements I {
+    y: number;
+}
+
+class Bar8 extends Foo implements I {
+    x: string;
+    y: number;
+}
diff --git a/tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds.ts b/tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds.ts
new file mode 100644
index 00000000000..6a504a916da
--- /dev/null
+++ b/tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds.ts
@@ -0,0 +1,15 @@
+class Foo {
+    protected x: string;
+}
+
+interface I extends Foo { // error
+    x: string;
+}
+
+interface I2 extends Foo {
+    y: string;
+}
+
+var i: I2;
+var r = i.y;
+var r2 = i.x; // error
\ No newline at end of file
diff --git a/tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts b/tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts
new file mode 100644
index 00000000000..4663709bce8
--- /dev/null
+++ b/tests/cases/conformance/interfaces/interfacesExtendingClasses/interfaceExtendingClassWithProtecteds2.ts
@@ -0,0 +1,27 @@
+class Foo {
+    protected x: string;
+}
+
+class Bar {
+    protected x: string;
+}
+
+interface I3 extends Foo, Bar { // error
+}
+
+interface I4 extends Foo, Bar { // error
+    x: string;
+}
+
+class Baz {
+    protected y: string;
+}
+
+interface I5 extends Foo, Baz {
+    z: string;
+}
+
+var i: I5;
+var r: string = i.z;
+var r2 = i.x; // error
+var r3 = i.y; // error
\ No newline at end of file