diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 0ae33d08fd6..494570c85c1 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -388,23 +388,28 @@ module ts {
             bindChildren(node, /*symbolKind:*/ 0, /*isBlockScopeContainer:*/ true);
         }
 
-        function bindBlockScopedVariableDeclaration(node: Declaration) {
+        function bindBlockScopedDeclaration(node: Declaration, symbolKind: SymbolFlags, symbolExcludes: SymbolFlags) {
             switch (blockScopeContainer.kind) {
                 case SyntaxKind.ModuleDeclaration:
-                    declareModuleMember(node, SymbolFlags.BlockScopedVariable, SymbolFlags.BlockScopedVariableExcludes);
+                    declareModuleMember(node, symbolKind, symbolExcludes);
                     break;
                 case SyntaxKind.SourceFile:
                     if (isExternalModule(<SourceFile>container)) {
-                        declareModuleMember(node, SymbolFlags.BlockScopedVariable, SymbolFlags.BlockScopedVariableExcludes);
+                        declareModuleMember(node, symbolKind, symbolExcludes);
                         break;
                     }
+                    // fall through.
                 default:
                     if (!blockScopeContainer.locals) {
                         blockScopeContainer.locals = {};
                     }
-                    declareSymbol(blockScopeContainer.locals, undefined, node, SymbolFlags.BlockScopedVariable, SymbolFlags.BlockScopedVariableExcludes);
+                    declareSymbol(blockScopeContainer.locals, undefined, node, symbolKind, symbolExcludes);
             }
-            bindChildren(node, SymbolFlags.BlockScopedVariable, /*isBlockScopeContainer*/ false);
+            bindChildren(node, symbolKind, /*isBlockScopeContainer*/ false);
+        }
+
+        function bindBlockScopedVariableDeclaration(node: Declaration) {
+            bindBlockScopedDeclaration(node, SymbolFlags.BlockScopedVariable, SymbolFlags.BlockScopedVariableExcludes);
         }
 
         function getDestructuringParameterName(node: Declaration) {
@@ -493,7 +498,7 @@ module ts {
                     bindCatchVariableDeclaration(<CatchClause>node);
                     break;
                 case SyntaxKind.ClassDeclaration:
-                    bindDeclaration(<Declaration>node, SymbolFlags.Class, SymbolFlags.ClassExcludes, /*isBlockScopeContainer*/ false);
+                    bindBlockScopedDeclaration(<Declaration>node, SymbolFlags.Class, SymbolFlags.ClassExcludes);
                     break;
                 case SyntaxKind.InterfaceDeclaration:
                     bindDeclaration(<Declaration>node, SymbolFlags.Interface, SymbolFlags.InterfaceExcludes, /*isBlockScopeContainer*/ false);
diff --git a/tests/baselines/reference/classDeclarationBlockScoping1.errors.txt b/tests/baselines/reference/classDeclarationBlockScoping1.errors.txt
new file mode 100644
index 00000000000..4f15007bb2a
--- /dev/null
+++ b/tests/baselines/reference/classDeclarationBlockScoping1.errors.txt
@@ -0,0 +1,13 @@
+tests/cases/compiler/classDeclarationBlockScoping1.ts(5,11): error TS9004: 'class' declarations are only supported directly inside a module or as a top level declaration.
+
+
+==== tests/cases/compiler/classDeclarationBlockScoping1.ts (1 errors) ====
+    class C {
+    }
+    
+    {
+        class C {
+              ~
+!!! error TS9004: 'class' declarations are only supported directly inside a module or as a top level declaration.
+        }
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/classDeclarationBlockScoping1.js b/tests/baselines/reference/classDeclarationBlockScoping1.js
new file mode 100644
index 00000000000..717c2f788c3
--- /dev/null
+++ b/tests/baselines/reference/classDeclarationBlockScoping1.js
@@ -0,0 +1,22 @@
+//// [classDeclarationBlockScoping1.ts]
+class C {
+}
+
+{
+    class C {
+    }
+}
+
+//// [classDeclarationBlockScoping1.js]
+var C = (function () {
+    function C() {
+    }
+    return C;
+})();
+{
+    var C = (function () {
+        function C() {
+        }
+        return C;
+    })();
+}
diff --git a/tests/baselines/reference/classDeclarationBlockScoping2.errors.txt b/tests/baselines/reference/classDeclarationBlockScoping2.errors.txt
new file mode 100644
index 00000000000..2a9885e110b
--- /dev/null
+++ b/tests/baselines/reference/classDeclarationBlockScoping2.errors.txt
@@ -0,0 +1,18 @@
+tests/cases/compiler/classDeclarationBlockScoping2.ts(2,11): error TS9004: 'class' declarations are only supported directly inside a module or as a top level declaration.
+tests/cases/compiler/classDeclarationBlockScoping2.ts(5,15): error TS9004: 'class' declarations are only supported directly inside a module or as a top level declaration.
+
+
+==== tests/cases/compiler/classDeclarationBlockScoping2.ts (2 errors) ====
+    function f() {
+        class C {}
+              ~
+!!! error TS9004: 'class' declarations are only supported directly inside a module or as a top level declaration.
+        var c1 = C;
+        {
+            class C {}
+                  ~
+!!! error TS9004: 'class' declarations are only supported directly inside a module or as a top level declaration.
+            var c2 = C;
+        }
+        return C === c1;
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/classDeclarationBlockScoping2.js b/tests/baselines/reference/classDeclarationBlockScoping2.js
new file mode 100644
index 00000000000..9e468077119
--- /dev/null
+++ b/tests/baselines/reference/classDeclarationBlockScoping2.js
@@ -0,0 +1,29 @@
+//// [classDeclarationBlockScoping2.ts]
+function f() {
+    class C {}
+    var c1 = C;
+    {
+        class C {}
+        var c2 = C;
+    }
+    return C === c1;
+}
+
+//// [classDeclarationBlockScoping2.js]
+function f() {
+    var C = (function () {
+        function C() {
+        }
+        return C;
+    })();
+    var c1 = C;
+    {
+        var C = (function () {
+            function C() {
+            }
+            return C;
+        })();
+        var c2 = C;
+    }
+    return C === c1;
+}
diff --git a/tests/baselines/reference/externModule.errors.txt b/tests/baselines/reference/externModule.errors.txt
index d16c71ab05b..8d4126350c1 100644
--- a/tests/baselines/reference/externModule.errors.txt
+++ b/tests/baselines/reference/externModule.errors.txt
@@ -8,9 +8,13 @@ tests/cases/compiler/externModule.ts(18,6): error TS2390: Constructor implementa
 tests/cases/compiler/externModule.ts(20,13): error TS2391: Function implementation is missing or not immediately following the declaration.
 tests/cases/compiler/externModule.ts(26,13): error TS2391: Function implementation is missing or not immediately following the declaration.
 tests/cases/compiler/externModule.ts(28,13): error TS2391: Function implementation is missing or not immediately following the declaration.
+tests/cases/compiler/externModule.ts(32,11): error TS2304: Cannot find name 'XDate'.
+tests/cases/compiler/externModule.ts(34,7): error TS2304: Cannot find name 'XDate'.
+tests/cases/compiler/externModule.ts(36,7): error TS2304: Cannot find name 'XDate'.
+tests/cases/compiler/externModule.ts(37,3): error TS2304: Cannot find name 'XDate'.
 
 
-==== tests/cases/compiler/externModule.ts (10 errors) ====
+==== tests/cases/compiler/externModule.ts (14 errors) ====
     declare module {
     ~~~~~~~
 !!! error TS2304: Cannot find name 'declare'.
@@ -63,10 +67,18 @@ tests/cases/compiler/externModule.ts(28,13): error TS2391: Function implementati
     }
     
     var d=new XDate();
+              ~~~~~
+!!! error TS2304: Cannot find name 'XDate'.
     d.getDay();
     d=new XDate(1978,2);
+          ~~~~~
+!!! error TS2304: Cannot find name 'XDate'.
     d.getXDate();
     var n=XDate.parse("3/2/2004");
+          ~~~~~
+!!! error TS2304: Cannot find name 'XDate'.
     n=XDate.UTC(1964,2,1);
+      ~~~~~
+!!! error TS2304: Cannot find name 'XDate'.
     
     
\ No newline at end of file
diff --git a/tests/cases/compiler/classDeclarationBlockScoping1.ts b/tests/cases/compiler/classDeclarationBlockScoping1.ts
new file mode 100644
index 00000000000..b6012f785b6
--- /dev/null
+++ b/tests/cases/compiler/classDeclarationBlockScoping1.ts
@@ -0,0 +1,7 @@
+class C {
+}
+
+{
+    class C {
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/classDeclarationBlockScoping2.ts b/tests/cases/compiler/classDeclarationBlockScoping2.ts
new file mode 100644
index 00000000000..2a0c4c1213f
--- /dev/null
+++ b/tests/cases/compiler/classDeclarationBlockScoping2.ts
@@ -0,0 +1,9 @@
+function f() {
+    class C {}
+    var c1 = C;
+    {
+        class C {}
+        var c2 = C;
+    }
+    return C === c1;
+}
\ No newline at end of file