diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 3959335542c..cc876f4e8cf 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -84,8 +84,13 @@ module ts {
                     if (node.name) {
                         node.name.parent = node;
                     }
-                    file.semanticErrors.push(createDiagnosticForNode(node.name ? node.name : node,
-                        Diagnostics.Duplicate_identifier_0, getDisplayName(node)));
+                    // Report errors every position with duplicate declaration
+                    // Report errors on previous encountered declarations
+                    forEach(symbol.declarations, (declaration) => {
+                        file.semanticErrors.push(createDiagnosticForNode(declaration.name, Diagnostics.Duplicate_identifier_0, getDisplayName(declaration)));
+                    });
+                    file.semanticErrors.push(createDiagnosticForNode(node.name, Diagnostics.Duplicate_identifier_0, getDisplayName(node)));
+
                     symbol = createSymbol(0, name);
                 }
             }
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 834d85616f3..6adea60304d 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5696,6 +5696,8 @@ module ts {
             // when checking exported function declarations across modules check only duplicate implementations
             // names and consistency of modifiers are verified when we check local symbol
             var isExportSymbolInsideModule = symbol.parent && symbol.parent.flags & SymbolFlags.Module;
+            var duplicateFunctionDeclaration = false;
+            var multipleConstructorImplementation = false;
             for (var i = 0; i < declarations.length; i++) {
                 var node = <FunctionDeclaration>declarations[i];
                 var inAmbientContext = isInAmbientContext(node);
@@ -5718,10 +5720,10 @@ module ts {
 
                     if (node.body && bodyDeclaration) {
                         if (isConstructor) {
-                            error(node, Diagnostics.Multiple_constructor_implementations_are_not_allowed);
+                            multipleConstructorImplementation = true;
                         }
                         else {
-                            error(node, Diagnostics.Duplicate_function_implementation);
+                            duplicateFunctionDeclaration = true;
                         }
                     }
                     else if (!isExportSymbolInsideModule && previousDeclaration && previousDeclaration.parent === node.parent && previousDeclaration.end !== node.pos) {
@@ -5745,6 +5747,18 @@ module ts {
                 }
             }
 
+            if (multipleConstructorImplementation) {
+                forEach(declarations, declaration => {
+                    error(declaration, Diagnostics.Multiple_constructor_implementations_are_not_allowed);
+                });
+            }
+
+            if (duplicateFunctionDeclaration) {
+                forEach( declarations, declaration => {
+                    error(declaration.name, Diagnostics.Duplicate_function_implementation);
+                });
+            }
+
             if (!isExportSymbolInsideModule && lastSeenNonAmbientDeclaration && !lastSeenNonAmbientDeclaration.body) {
                 reportImplementationExpectedError(lastSeenNonAmbientDeclaration);
             }
diff --git a/tests/baselines/reference/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndGenericClassStaticFunctionOfTheSameName.errors.txt b/tests/baselines/reference/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndGenericClassStaticFunctionOfTheSameName.errors.txt
index 2ab89730405..d200258fdb1 100644
--- a/tests/baselines/reference/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndGenericClassStaticFunctionOfTheSameName.errors.txt
+++ b/tests/baselines/reference/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndGenericClassStaticFunctionOfTheSameName.errors.txt
@@ -1,12 +1,15 @@
+tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndGenericClassStaticFunctionOfTheSameName.ts(5,12): error TS2300: Duplicate identifier 'fn'.
 tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndGenericClassStaticFunctionOfTheSameName.ts(10,21): error TS2300: Duplicate identifier 'fn'.
 
 
-==== tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndGenericClassStaticFunctionOfTheSameName.ts (1 errors) ====
+==== tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndGenericClassStaticFunctionOfTheSameName.ts (2 errors) ====
     class clodule<T> {
         id: string;
         value: T;
     
         static fn<U>(id: U) { }
+               ~~
+!!! error TS2300: Duplicate identifier 'fn'.
     }
     
     module clodule {
diff --git a/tests/baselines/reference/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndNonGenericClassStaticFunctionOfTheSameName.errors.txt b/tests/baselines/reference/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndNonGenericClassStaticFunctionOfTheSameName.errors.txt
index 5db506d1052..474613e283f 100644
--- a/tests/baselines/reference/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndNonGenericClassStaticFunctionOfTheSameName.errors.txt
+++ b/tests/baselines/reference/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndNonGenericClassStaticFunctionOfTheSameName.errors.txt
@@ -1,12 +1,15 @@
+tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndNonGenericClassStaticFunctionOfTheSameName.ts(5,12): error TS2300: Duplicate identifier 'fn'.
 tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndNonGenericClassStaticFunctionOfTheSameName.ts(10,21): error TS2300: Duplicate identifier 'fn'.
 
 
-==== tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndNonGenericClassStaticFunctionOfTheSameName.ts (1 errors) ====
+==== tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithModulesExportedGenericFunctionAndNonGenericClassStaticFunctionOfTheSameName.ts (2 errors) ====
     class clodule<T> {
         id: string;
         value: T;
     
         static fn(id: string) { }
+               ~~
+!!! error TS2300: Duplicate identifier 'fn'.
     }
     
     module clodule {
diff --git a/tests/baselines/reference/ClassAndModuleThatMergeWithStaticFunctionAndExportedFunctionThatShareAName.errors.txt b/tests/baselines/reference/ClassAndModuleThatMergeWithStaticFunctionAndExportedFunctionThatShareAName.errors.txt
index 9b62647f40b..a59953e7fb2 100644
--- a/tests/baselines/reference/ClassAndModuleThatMergeWithStaticFunctionAndExportedFunctionThatShareAName.errors.txt
+++ b/tests/baselines/reference/ClassAndModuleThatMergeWithStaticFunctionAndExportedFunctionThatShareAName.errors.txt
@@ -1,12 +1,16 @@
+tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticFunctionAndExportedFunctionThatShareAName.ts(4,12): error TS2300: Duplicate identifier 'Origin'.
 tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticFunctionAndExportedFunctionThatShareAName.ts(8,21): error TS2300: Duplicate identifier 'Origin'.
+tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticFunctionAndExportedFunctionThatShareAName.ts(16,16): error TS2300: Duplicate identifier 'Origin'.
 tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticFunctionAndExportedFunctionThatShareAName.ts(20,25): error TS2300: Duplicate identifier 'Origin'.
 
 
-==== tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticFunctionAndExportedFunctionThatShareAName.ts (2 errors) ====
+==== tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticFunctionAndExportedFunctionThatShareAName.ts (4 errors) ====
     class Point {
         constructor(public x: number, public y: number) { }
     
         static Origin(): Point { return { x: 0, y: 0 }; } // unexpected error here bug 840246
+               ~~~~~~
+!!! error TS2300: Duplicate identifier 'Origin'.
     }
     
     module Point {
@@ -21,6 +25,8 @@ tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMer
             constructor(public x: number, public y: number) { }
     
             static Origin(): Point { return { x: 0, y: 0 }; } // unexpected error here bug 840246
+                   ~~~~~~
+!!! error TS2300: Duplicate identifier 'Origin'.
         }
     
         export module Point {
diff --git a/tests/baselines/reference/ClassAndModuleThatMergeWithStaticVariableAndExportedVarThatShareAName.errors.txt b/tests/baselines/reference/ClassAndModuleThatMergeWithStaticVariableAndExportedVarThatShareAName.errors.txt
index b160146f6f7..88ad9f358be 100644
--- a/tests/baselines/reference/ClassAndModuleThatMergeWithStaticVariableAndExportedVarThatShareAName.errors.txt
+++ b/tests/baselines/reference/ClassAndModuleThatMergeWithStaticVariableAndExportedVarThatShareAName.errors.txt
@@ -1,12 +1,16 @@
+tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticVariableAndExportedVarThatShareAName.ts(4,12): error TS2300: Duplicate identifier 'Origin'.
 tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticVariableAndExportedVarThatShareAName.ts(8,16): error TS2300: Duplicate identifier 'Origin'.
+tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticVariableAndExportedVarThatShareAName.ts(16,16): error TS2300: Duplicate identifier 'Origin'.
 tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticVariableAndExportedVarThatShareAName.ts(20,20): error TS2300: Duplicate identifier 'Origin'.
 
 
-==== tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticVariableAndExportedVarThatShareAName.ts (2 errors) ====
+==== tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMergeWithStaticVariableAndExportedVarThatShareAName.ts (4 errors) ====
     class Point {
         constructor(public x: number, public y: number) { }
     
         static Origin: Point = { x: 0, y: 0 };
+               ~~~~~~
+!!! error TS2300: Duplicate identifier 'Origin'.
     }
     
     module Point {
@@ -21,6 +25,8 @@ tests/cases/conformance/internalModules/DeclarationMerging/ClassAndModuleThatMer
             constructor(public x: number, public y: number) { }
     
             static Origin: Point = { x: 0, y: 0 };
+                   ~~~~~~
+!!! error TS2300: Duplicate identifier 'Origin'.
         }
     
         export module Point {
diff --git a/tests/baselines/reference/TwoInternalModulesThatMergeEachWithExportedClassesOfTheSameName.errors.txt b/tests/baselines/reference/TwoInternalModulesThatMergeEachWithExportedClassesOfTheSameName.errors.txt
index fd9c4bc0ffe..39e5278041d 100644
--- a/tests/baselines/reference/TwoInternalModulesThatMergeEachWithExportedClassesOfTheSameName.errors.txt
+++ b/tests/baselines/reference/TwoInternalModulesThatMergeEachWithExportedClassesOfTheSameName.errors.txt
@@ -1,10 +1,14 @@
+tests/cases/conformance/internalModules/DeclarationMerging/TwoInternalModulesThatMergeEachWithExportedClassesOfTheSameName.ts(2,18): error TS2300: Duplicate identifier 'Point'.
 tests/cases/conformance/internalModules/DeclarationMerging/TwoInternalModulesThatMergeEachWithExportedClassesOfTheSameName.ts(10,18): error TS2300: Duplicate identifier 'Point'.
+tests/cases/conformance/internalModules/DeclarationMerging/TwoInternalModulesThatMergeEachWithExportedClassesOfTheSameName.ts(17,18): error TS2300: Duplicate identifier 'Line'.
 tests/cases/conformance/internalModules/DeclarationMerging/TwoInternalModulesThatMergeEachWithExportedClassesOfTheSameName.ts(26,26): error TS2300: Duplicate identifier 'Line'.
 
 
-==== tests/cases/conformance/internalModules/DeclarationMerging/TwoInternalModulesThatMergeEachWithExportedClassesOfTheSameName.ts (2 errors) ====
+==== tests/cases/conformance/internalModules/DeclarationMerging/TwoInternalModulesThatMergeEachWithExportedClassesOfTheSameName.ts (4 errors) ====
     module A {
         export class Point {
+                     ~~~~~
+!!! error TS2300: Duplicate identifier 'Point'.
             x: number;
             y: number;
         }
@@ -22,6 +26,8 @@ tests/cases/conformance/internalModules/DeclarationMerging/TwoInternalModulesTha
     
     module X.Y.Z {
         export class Line {
+                     ~~~~
+!!! error TS2300: Duplicate identifier 'Line'.
             length: number;
         }
     }
diff --git a/tests/baselines/reference/ambientClassOverloadForFunction.errors.txt b/tests/baselines/reference/ambientClassOverloadForFunction.errors.txt
index e7ace55872a..16df32bb2c5 100644
--- a/tests/baselines/reference/ambientClassOverloadForFunction.errors.txt
+++ b/tests/baselines/reference/ambientClassOverloadForFunction.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/ambientClassOverloadForFunction.ts(1,15): error TS2300: Duplicate identifier 'foo'.
 tests/cases/compiler/ambientClassOverloadForFunction.ts(2,10): error TS2300: Duplicate identifier 'foo'.
 
 
-==== tests/cases/compiler/ambientClassOverloadForFunction.ts (1 errors) ====
+==== tests/cases/compiler/ambientClassOverloadForFunction.ts (2 errors) ====
     declare class foo{};
+                  ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
     function foo() { return null; }
              ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
diff --git a/tests/baselines/reference/anyDeclare.errors.txt b/tests/baselines/reference/anyDeclare.errors.txt
index c9728323818..8eda3672f24 100644
--- a/tests/baselines/reference/anyDeclare.errors.txt
+++ b/tests/baselines/reference/anyDeclare.errors.txt
@@ -1,10 +1,13 @@
+tests/cases/compiler/anyDeclare.ts(3,9): error TS2300: Duplicate identifier 'myFn'.
 tests/cases/compiler/anyDeclare.ts(4,14): error TS2300: Duplicate identifier 'myFn'.
 
 
-==== tests/cases/compiler/anyDeclare.ts (1 errors) ====
+==== tests/cases/compiler/anyDeclare.ts (2 errors) ====
     declare var x: any;
     module myMod {
         var myFn;
+            ~~~~
+!!! error TS2300: Duplicate identifier 'myFn'.
         function myFn() {  }
                  ~~~~
 !!! error TS2300: Duplicate identifier 'myFn'.
diff --git a/tests/baselines/reference/augmentedTypesClass.errors.txt b/tests/baselines/reference/augmentedTypesClass.errors.txt
index 16faa14b4c2..2ff6889e22f 100644
--- a/tests/baselines/reference/augmentedTypesClass.errors.txt
+++ b/tests/baselines/reference/augmentedTypesClass.errors.txt
@@ -1,16 +1,22 @@
+tests/cases/compiler/augmentedTypesClass.ts(2,7): error TS2300: Duplicate identifier 'c1'.
 tests/cases/compiler/augmentedTypesClass.ts(3,5): error TS2300: Duplicate identifier 'c1'.
+tests/cases/compiler/augmentedTypesClass.ts(6,7): error TS2300: Duplicate identifier 'c4'.
 tests/cases/compiler/augmentedTypesClass.ts(7,6): error TS2300: Duplicate identifier 'c4'.
 
 
-==== tests/cases/compiler/augmentedTypesClass.ts (2 errors) ====
+==== tests/cases/compiler/augmentedTypesClass.ts (4 errors) ====
     //// class then var
     class c1 { public foo() { } }
+          ~~
+!!! error TS2300: Duplicate identifier 'c1'.
     var c1 = 1; // error
         ~~
 !!! error TS2300: Duplicate identifier 'c1'.
     
     //// class then enum
     class c4 { public foo() { } }
+          ~~
+!!! error TS2300: Duplicate identifier 'c4'.
     enum c4 { One } // error
          ~~
 !!! error TS2300: Duplicate identifier 'c4'.
\ No newline at end of file
diff --git a/tests/baselines/reference/augmentedTypesClass2.errors.txt b/tests/baselines/reference/augmentedTypesClass2.errors.txt
index 32104b65ac5..5881e49dae9 100644
--- a/tests/baselines/reference/augmentedTypesClass2.errors.txt
+++ b/tests/baselines/reference/augmentedTypesClass2.errors.txt
@@ -1,12 +1,16 @@
+tests/cases/compiler/augmentedTypesClass2.ts(4,7): error TS2300: Duplicate identifier 'c11'.
 tests/cases/compiler/augmentedTypesClass2.ts(10,11): error TS2300: Duplicate identifier 'c11'.
+tests/cases/compiler/augmentedTypesClass2.ts(16,7): error TS2300: Duplicate identifier 'c33'.
 tests/cases/compiler/augmentedTypesClass2.ts(21,6): error TS2300: Duplicate identifier 'c33'.
 
 
-==== tests/cases/compiler/augmentedTypesClass2.ts (2 errors) ====
+==== tests/cases/compiler/augmentedTypesClass2.ts (4 errors) ====
     // Checking class with other things in type space not value space
     
     // class then interface
-    class c11 {
+    class c11 { // error
+          ~~~
+!!! error TS2300: Duplicate identifier 'c11'.
         foo() {
             return 1;
         }
@@ -21,6 +25,8 @@ tests/cases/compiler/augmentedTypesClass2.ts(21,6): error TS2300: Duplicate iden
     // class then class - covered
     // class then enum 
     class c33 {
+          ~~~
+!!! error TS2300: Duplicate identifier 'c33'.
         foo() {
             return 1;
         }
diff --git a/tests/baselines/reference/augmentedTypesClass2.js b/tests/baselines/reference/augmentedTypesClass2.js
index b4df1672b69..f75c08a5920 100644
--- a/tests/baselines/reference/augmentedTypesClass2.js
+++ b/tests/baselines/reference/augmentedTypesClass2.js
@@ -2,7 +2,7 @@
 // Checking class with other things in type space not value space
 
 // class then interface
-class c11 {
+class c11 { // error
     foo() {
         return 1;
     }
diff --git a/tests/baselines/reference/augmentedTypesClass2a.errors.txt b/tests/baselines/reference/augmentedTypesClass2a.errors.txt
index 74dece080a6..b17ab32d408 100644
--- a/tests/baselines/reference/augmentedTypesClass2a.errors.txt
+++ b/tests/baselines/reference/augmentedTypesClass2a.errors.txt
@@ -1,10 +1,13 @@
+tests/cases/compiler/augmentedTypesClass2a.ts(2,7): error TS2300: Duplicate identifier 'c2'.
 tests/cases/compiler/augmentedTypesClass2a.ts(3,10): error TS2300: Duplicate identifier 'c2'.
 tests/cases/compiler/augmentedTypesClass2a.ts(4,5): error TS2300: Duplicate identifier 'c2'.
 
 
-==== tests/cases/compiler/augmentedTypesClass2a.ts (2 errors) ====
+==== tests/cases/compiler/augmentedTypesClass2a.ts (3 errors) ====
     //// class then function
-    class c2 { public foo() { } }
+    class c2 { public foo() { } } // error
+          ~~
+!!! error TS2300: Duplicate identifier 'c2'.
     function c2() { } // error
              ~~
 !!! error TS2300: Duplicate identifier 'c2'.
diff --git a/tests/baselines/reference/augmentedTypesClass2a.js b/tests/baselines/reference/augmentedTypesClass2a.js
index cca45c2c0b3..fe31f0964c2 100644
--- a/tests/baselines/reference/augmentedTypesClass2a.js
+++ b/tests/baselines/reference/augmentedTypesClass2a.js
@@ -1,6 +1,6 @@
 //// [augmentedTypesClass2a.ts]
 //// class then function
-class c2 { public foo() { } }
+class c2 { public foo() { } } // error
 function c2() { } // error
 var c2 = () => { }
 
@@ -12,7 +12,7 @@ var c2 = (function () {
     c2.prototype.foo = function () {
     };
     return c2;
-})();
+})(); // error
 function c2() {
 } // error
 var c2 = function () {
diff --git a/tests/baselines/reference/augmentedTypesClass4.errors.txt b/tests/baselines/reference/augmentedTypesClass4.errors.txt
index 2df0a95ccd2..6df027ca511 100644
--- a/tests/baselines/reference/augmentedTypesClass4.errors.txt
+++ b/tests/baselines/reference/augmentedTypesClass4.errors.txt
@@ -1,9 +1,12 @@
+tests/cases/compiler/augmentedTypesClass4.ts(2,7): error TS2300: Duplicate identifier 'c3'.
 tests/cases/compiler/augmentedTypesClass4.ts(3,7): error TS2300: Duplicate identifier 'c3'.
 
 
-==== tests/cases/compiler/augmentedTypesClass4.ts (1 errors) ====
+==== tests/cases/compiler/augmentedTypesClass4.ts (2 errors) ====
     //// class then class
-    class c3 { public foo() { } }
+    class c3 { public foo() { } } // error
+          ~~
+!!! error TS2300: Duplicate identifier 'c3'.
     class c3 { public bar() { } } // error
           ~~
 !!! error TS2300: Duplicate identifier 'c3'.
diff --git a/tests/baselines/reference/augmentedTypesClass4.js b/tests/baselines/reference/augmentedTypesClass4.js
index c4e104e714b..71fc61d6659 100644
--- a/tests/baselines/reference/augmentedTypesClass4.js
+++ b/tests/baselines/reference/augmentedTypesClass4.js
@@ -1,6 +1,6 @@
 //// [augmentedTypesClass4.ts]
 //// class then class
-class c3 { public foo() { } }
+class c3 { public foo() { } } // error
 class c3 { public bar() { } } // error
 
 
@@ -12,7 +12,7 @@ var c3 = (function () {
     c3.prototype.foo = function () {
     };
     return c3;
-})();
+})(); // error
 var c3 = (function () {
     function c3() {
     }
diff --git a/tests/baselines/reference/augmentedTypesEnum.errors.txt b/tests/baselines/reference/augmentedTypesEnum.errors.txt
index 374ca14093b..3102f9d4786 100644
--- a/tests/baselines/reference/augmentedTypesEnum.errors.txt
+++ b/tests/baselines/reference/augmentedTypesEnum.errors.txt
@@ -1,43 +1,58 @@
+tests/cases/compiler/augmentedTypesEnum.ts(2,6): error TS2300: Duplicate identifier 'e1111'.
 tests/cases/compiler/augmentedTypesEnum.ts(3,5): error TS2300: Duplicate identifier 'e1111'.
+tests/cases/compiler/augmentedTypesEnum.ts(6,6): error TS2300: Duplicate identifier 'e2'.
 tests/cases/compiler/augmentedTypesEnum.ts(7,10): error TS2300: Duplicate identifier 'e2'.
+tests/cases/compiler/augmentedTypesEnum.ts(9,6): error TS2300: Duplicate identifier 'e3'.
 tests/cases/compiler/augmentedTypesEnum.ts(10,5): error TS2300: Duplicate identifier 'e3'.
+tests/cases/compiler/augmentedTypesEnum.ts(13,6): error TS2300: Duplicate identifier 'e4'.
 tests/cases/compiler/augmentedTypesEnum.ts(14,7): error TS2300: Duplicate identifier 'e4'.
 tests/cases/compiler/augmentedTypesEnum.ts(18,11): error TS2432: In an enum with multiple declarations, only one declaration can omit an initializer for its first enum element.
+tests/cases/compiler/augmentedTypesEnum.ts(20,12): error TS2300: Duplicate identifier 'One'.
 tests/cases/compiler/augmentedTypesEnum.ts(21,12): error TS2300: Duplicate identifier 'One'.
 tests/cases/compiler/augmentedTypesEnum.ts(21,12): error TS2432: In an enum with multiple declarations, only one declaration can omit an initializer for its first enum element.
 
 
-==== tests/cases/compiler/augmentedTypesEnum.ts (7 errors) ====
+==== tests/cases/compiler/augmentedTypesEnum.ts (12 errors) ====
     // enum then var
-    enum e1111 { One }
+    enum e1111 { One } // error
+         ~~~~~
+!!! error TS2300: Duplicate identifier 'e1111'.
     var e1111 = 1; // error
         ~~~~~
 !!! error TS2300: Duplicate identifier 'e1111'.
     
     // enum then function
-    enum e2 { One }
+    enum e2 { One } // error
+         ~~
+!!! error TS2300: Duplicate identifier 'e2'.
     function e2() { } // error
              ~~
 !!! error TS2300: Duplicate identifier 'e2'.
     
-    enum e3 { One }
+    enum e3 { One } // error
+         ~~
+!!! error TS2300: Duplicate identifier 'e3'.
     var e3 = () => { } // error
         ~~
 !!! error TS2300: Duplicate identifier 'e3'.
     
     // enum then class
-    enum e4 { One }
+    enum e4 { One } // error
+         ~~
+!!! error TS2300: Duplicate identifier 'e4'.
     class e4 { public foo() { } } // error
           ~~
 !!! error TS2300: Duplicate identifier 'e4'.
     
     // enum then enum
     enum e5 { One }
-    enum e5 { Two }
+    enum e5 { Two } // error
               ~~~
 !!! error TS2432: In an enum with multiple declarations, only one declaration can omit an initializer for its first enum element.
     
-    enum e5a { One }
+    enum e5a { One } // error
+               ~~~
+!!! error TS2300: Duplicate identifier 'One'.
     enum e5a { One } // error
                ~~~
 !!! error TS2300: Duplicate identifier 'One'.
diff --git a/tests/baselines/reference/augmentedTypesEnum.js b/tests/baselines/reference/augmentedTypesEnum.js
index 8422b99798b..f7a83018cfd 100644
--- a/tests/baselines/reference/augmentedTypesEnum.js
+++ b/tests/baselines/reference/augmentedTypesEnum.js
@@ -1,24 +1,24 @@
 //// [augmentedTypesEnum.ts]
 // enum then var
-enum e1111 { One }
+enum e1111 { One } // error
 var e1111 = 1; // error
 
 // enum then function
-enum e2 { One }
+enum e2 { One } // error
 function e2() { } // error
 
-enum e3 { One }
+enum e3 { One } // error
 var e3 = () => { } // error
 
 // enum then class
-enum e4 { One }
+enum e4 { One } // error
 class e4 { public foo() { } } // error
 
 // enum then enum
 enum e5 { One }
-enum e5 { Two }
+enum e5 { Two } // error
 
-enum e5a { One }
+enum e5a { One } // error
 enum e5a { One } // error
 
 // enum then internal module
@@ -40,26 +40,26 @@ module e6b { export var y = 2; } // should be error
 var e1111;
 (function (e1111) {
     e1111[e1111["One"] = 0] = "One";
-})(e1111 || (e1111 = {}));
+})(e1111 || (e1111 = {})); // error
 var e1111 = 1; // error
 // enum then function
 var e2;
 (function (e2) {
     e2[e2["One"] = 0] = "One";
-})(e2 || (e2 = {}));
+})(e2 || (e2 = {})); // error
 function e2() {
 } // error
 var e3;
 (function (e3) {
     e3[e3["One"] = 0] = "One";
-})(e3 || (e3 = {}));
+})(e3 || (e3 = {})); // error
 var e3 = function () {
 }; // error
 // enum then class
 var e4;
 (function (e4) {
     e4[e4["One"] = 0] = "One";
-})(e4 || (e4 = {}));
+})(e4 || (e4 = {})); // error
 var e4 = (function () {
     function e4() {
     }
@@ -75,11 +75,11 @@ var e5;
 var e5;
 (function (e5) {
     e5[e5["Two"] = 0] = "Two";
-})(e5 || (e5 = {}));
+})(e5 || (e5 = {})); // error
 var e5a;
 (function (e5a) {
     e5a[e5a["One"] = 0] = "One";
-})(e5a || (e5a = {}));
+})(e5a || (e5a = {})); // error
 var e5a;
 (function (e5a) {
     e5a[e5a["One"] = 0] = "One";
diff --git a/tests/baselines/reference/augmentedTypesEnum2.errors.txt b/tests/baselines/reference/augmentedTypesEnum2.errors.txt
index 86e155f8772..8c6c7382f85 100644
--- a/tests/baselines/reference/augmentedTypesEnum2.errors.txt
+++ b/tests/baselines/reference/augmentedTypesEnum2.errors.txt
@@ -1,12 +1,16 @@
+tests/cases/compiler/augmentedTypesEnum2.ts(2,6): error TS2300: Duplicate identifier 'e1'.
 tests/cases/compiler/augmentedTypesEnum2.ts(4,11): error TS2300: Duplicate identifier 'e1'.
+tests/cases/compiler/augmentedTypesEnum2.ts(11,6): error TS2300: Duplicate identifier 'e2'.
 tests/cases/compiler/augmentedTypesEnum2.ts(12,7): error TS2300: Duplicate identifier 'e2'.
 
 
-==== tests/cases/compiler/augmentedTypesEnum2.ts (2 errors) ====
+==== tests/cases/compiler/augmentedTypesEnum2.ts (4 errors) ====
     // enum then interface
-    enum e1 { One }
+    enum e1 { One } // error
+         ~~
+!!! error TS2300: Duplicate identifier 'e1'.
     
-    interface e1 {
+    interface e1 { // error
               ~~
 !!! error TS2300: Duplicate identifier 'e1'.
         foo(): void;
@@ -15,7 +19,9 @@ tests/cases/compiler/augmentedTypesEnum2.ts(12,7): error TS2300: Duplicate ident
     // interface then enum works
     
     // enum then class
-    enum e2 { One };
+    enum e2 { One }; // error
+         ~~
+!!! error TS2300: Duplicate identifier 'e2'.
     class e2 { // error
           ~~
 !!! error TS2300: Duplicate identifier 'e2'.
diff --git a/tests/baselines/reference/augmentedTypesEnum2.js b/tests/baselines/reference/augmentedTypesEnum2.js
index 13656b33411..8ab98a7cb7b 100644
--- a/tests/baselines/reference/augmentedTypesEnum2.js
+++ b/tests/baselines/reference/augmentedTypesEnum2.js
@@ -1,15 +1,15 @@
 //// [augmentedTypesEnum2.ts]
 // enum then interface
-enum e1 { One }
+enum e1 { One } // error
 
-interface e1 {
+interface e1 { // error
     foo(): void;
 }
 
 // interface then enum works
 
 // enum then class
-enum e2 { One };
+enum e2 { One }; // error
 class e2 { // error
     foo() {
         return 1;
@@ -24,7 +24,7 @@ class e2 { // error
 var e1;
 (function (e1) {
     e1[e1["One"] = 0] = "One";
-})(e1 || (e1 = {}));
+})(e1 || (e1 = {})); // error
 // interface then enum works
 // enum then class
 var e2;
diff --git a/tests/baselines/reference/augmentedTypesFunction.errors.txt b/tests/baselines/reference/augmentedTypesFunction.errors.txt
index ba324349c65..8d1ce671c9e 100644
--- a/tests/baselines/reference/augmentedTypesFunction.errors.txt
+++ b/tests/baselines/reference/augmentedTypesFunction.errors.txt
@@ -1,42 +1,60 @@
+tests/cases/compiler/augmentedTypesFunction.ts(2,10): error TS2300: Duplicate identifier 'y1'.
 tests/cases/compiler/augmentedTypesFunction.ts(3,5): error TS2300: Duplicate identifier 'y1'.
-tests/cases/compiler/augmentedTypesFunction.ts(7,1): error TS2393: Duplicate function implementation.
+tests/cases/compiler/augmentedTypesFunction.ts(6,10): error TS2393: Duplicate function implementation.
+tests/cases/compiler/augmentedTypesFunction.ts(7,10): error TS2393: Duplicate function implementation.
+tests/cases/compiler/augmentedTypesFunction.ts(9,10): error TS2300: Duplicate identifier 'y2a'.
 tests/cases/compiler/augmentedTypesFunction.ts(10,5): error TS2300: Duplicate identifier 'y2a'.
+tests/cases/compiler/augmentedTypesFunction.ts(13,10): error TS2300: Duplicate identifier 'y3'.
 tests/cases/compiler/augmentedTypesFunction.ts(14,7): error TS2300: Duplicate identifier 'y3'.
+tests/cases/compiler/augmentedTypesFunction.ts(16,10): error TS2300: Duplicate identifier 'y3a'.
 tests/cases/compiler/augmentedTypesFunction.ts(17,7): error TS2300: Duplicate identifier 'y3a'.
+tests/cases/compiler/augmentedTypesFunction.ts(20,10): error TS2300: Duplicate identifier 'y4'.
 tests/cases/compiler/augmentedTypesFunction.ts(21,6): error TS2300: Duplicate identifier 'y4'.
 
 
-==== tests/cases/compiler/augmentedTypesFunction.ts (6 errors) ====
+==== tests/cases/compiler/augmentedTypesFunction.ts (12 errors) ====
     // function then var
-    function y1() { }
+    function y1() { } // error
+             ~~
+!!! error TS2300: Duplicate identifier 'y1'.
     var y1 = 1; // error
         ~~
 !!! error TS2300: Duplicate identifier 'y1'.
     
     // function then function
-    function y2() { }
     function y2() { } // error
-    ~~~~~~~~~~~~~~~~~
+             ~~
+!!! error TS2393: Duplicate function implementation.
+    function y2() { } // error
+             ~~
 !!! error TS2393: Duplicate function implementation.
     
-    function y2a() { }
+    function y2a() { }  // error
+             ~~~
+!!! error TS2300: Duplicate identifier 'y2a'.
     var y2a = () => { } // error
         ~~~
 !!! error TS2300: Duplicate identifier 'y2a'.
     
     // function then class
-    function y3() { }
+    function y3() { } // error
+             ~~
+!!! error TS2300: Duplicate identifier 'y3'.
     class y3 { } // error
           ~~
 !!! error TS2300: Duplicate identifier 'y3'.
     
-    function y3a() { }
+    function y3a() { } // error
+             ~~~
+!!! error TS2300: Duplicate identifier 'y3a'.
     class y3a { public foo() { } } // error
           ~~~
 !!! error TS2300: Duplicate identifier 'y3a'.
     
     // function then enum
-    function y4() { }
+    function y4() { } // error
+             ~~
+!!! error TS2300: Duplicate identifier 'y4'.
     enum y4 { One } // error
          ~~
 !!! error TS2300: Duplicate identifier 'y4'.
diff --git a/tests/baselines/reference/augmentedTypesFunction.js b/tests/baselines/reference/augmentedTypesFunction.js
index 097482c7c5b..078854e227c 100644
--- a/tests/baselines/reference/augmentedTypesFunction.js
+++ b/tests/baselines/reference/augmentedTypesFunction.js
@@ -1,24 +1,24 @@
 //// [augmentedTypesFunction.ts]
 // function then var
-function y1() { }
+function y1() { } // error
 var y1 = 1; // error
 
 // function then function
-function y2() { }
+function y2() { } // error
 function y2() { } // error
 
-function y2a() { }
+function y2a() { }  // error
 var y2a = () => { } // error
 
 // function then class
-function y3() { }
+function y3() { } // error
 class y3 { } // error
 
-function y3a() { }
+function y3a() { } // error
 class y3a { public foo() { } } // error
 
 // function then enum
-function y4() { }
+function y4() { } // error
 enum y4 { One } // error
 
 // function then internal module
@@ -41,27 +41,27 @@ module y5c { export interface I { foo(): void } } // should be an error
 //// [augmentedTypesFunction.js]
 // function then var
 function y1() {
-}
+} // error
 var y1 = 1; // error
 // function then function
 function y2() {
-}
+} // error
 function y2() {
 } // error
 function y2a() {
-}
+} // error
 var y2a = function () {
 }; // error
 // function then class
 function y3() {
-}
+} // error
 var y3 = (function () {
     function y3() {
     }
     return y3;
 })(); // error
 function y3a() {
-}
+} // error
 var y3a = (function () {
     function y3a() {
     }
@@ -71,7 +71,7 @@ var y3a = (function () {
 })(); // error
 // function then enum
 function y4() {
-}
+} // error
 var y4;
 (function (y4) {
     y4[y4["One"] = 0] = "One";
diff --git a/tests/baselines/reference/augmentedTypesInterface.errors.txt b/tests/baselines/reference/augmentedTypesInterface.errors.txt
index 77a7fa64eed..a9fc28dd5ae 100644
--- a/tests/baselines/reference/augmentedTypesInterface.errors.txt
+++ b/tests/baselines/reference/augmentedTypesInterface.errors.txt
@@ -1,8 +1,10 @@
+tests/cases/compiler/augmentedTypesInterface.ts(12,11): error TS2300: Duplicate identifier 'i2'.
 tests/cases/compiler/augmentedTypesInterface.ts(16,7): error TS2300: Duplicate identifier 'i2'.
+tests/cases/compiler/augmentedTypesInterface.ts(23,11): error TS2300: Duplicate identifier 'i3'.
 tests/cases/compiler/augmentedTypesInterface.ts(26,6): error TS2300: Duplicate identifier 'i3'.
 
 
-==== tests/cases/compiler/augmentedTypesInterface.ts (2 errors) ====
+==== tests/cases/compiler/augmentedTypesInterface.ts (4 errors) ====
     // interface then interface
     
     interface i {
@@ -14,7 +16,9 @@ tests/cases/compiler/augmentedTypesInterface.ts(26,6): error TS2300: Duplicate i
     }
     
     // interface then class
-    interface i2 {
+    interface i2 { // error
+              ~~
+!!! error TS2300: Duplicate identifier 'i2'.
         foo(): void;
     }
     
@@ -27,7 +31,9 @@ tests/cases/compiler/augmentedTypesInterface.ts(26,6): error TS2300: Duplicate i
     }
     
     // interface then enum
-    interface i3 {
+    interface i3 { // error
+              ~~
+!!! error TS2300: Duplicate identifier 'i3'.
         foo(): void;
     }
     enum i3 { One }; // error
diff --git a/tests/baselines/reference/augmentedTypesInterface.js b/tests/baselines/reference/augmentedTypesInterface.js
index 5c68ba9a744..709b16d615c 100644
--- a/tests/baselines/reference/augmentedTypesInterface.js
+++ b/tests/baselines/reference/augmentedTypesInterface.js
@@ -10,7 +10,7 @@ interface i {
 }
 
 // interface then class
-interface i2 {
+interface i2 { // error
     foo(): void;
 }
 
@@ -21,7 +21,7 @@ class i2 {  // error
 }
 
 // interface then enum
-interface i3 {
+interface i3 { // error
     foo(): void;
 }
 enum i3 { One }; // error
diff --git a/tests/baselines/reference/augmentedTypesModules.errors.txt b/tests/baselines/reference/augmentedTypesModules.errors.txt
index 75b1973525d..980837a18ef 100644
--- a/tests/baselines/reference/augmentedTypesModules.errors.txt
+++ b/tests/baselines/reference/augmentedTypesModules.errors.txt
@@ -1,23 +1,30 @@
+tests/cases/compiler/augmentedTypesModules.ts(5,8): error TS2300: Duplicate identifier 'm1a'.
 tests/cases/compiler/augmentedTypesModules.ts(6,5): error TS2300: Duplicate identifier 'm1a'.
+tests/cases/compiler/augmentedTypesModules.ts(8,8): error TS2300: Duplicate identifier 'm1b'.
 tests/cases/compiler/augmentedTypesModules.ts(9,5): error TS2300: Duplicate identifier 'm1b'.
+tests/cases/compiler/augmentedTypesModules.ts(16,8): error TS2300: Duplicate identifier 'm1d'.
 tests/cases/compiler/augmentedTypesModules.ts(19,5): error TS2300: Duplicate identifier 'm1d'.
 tests/cases/compiler/augmentedTypesModules.ts(25,8): error TS2434: A module declaration cannot be located prior to a class or function with which it is merged
 tests/cases/compiler/augmentedTypesModules.ts(28,8): error TS2434: A module declaration cannot be located prior to a class or function with which it is merged
 tests/cases/compiler/augmentedTypesModules.ts(51,8): error TS2434: A module declaration cannot be located prior to a class or function with which it is merged
 
 
-==== tests/cases/compiler/augmentedTypesModules.ts (6 errors) ====
+==== tests/cases/compiler/augmentedTypesModules.ts (9 errors) ====
     // module then var
     module m1 { }
     var m1 = 1; // Should be allowed
     
-    module m1a { var y = 2; }
-    var m1a = 1;
+    module m1a { var y = 2; } // error
+           ~~~
+!!! error TS2300: Duplicate identifier 'm1a'.
+    var m1a = 1; // error
         ~~~
 !!! error TS2300: Duplicate identifier 'm1a'.
     
-    module m1b { export var y = 2; }
-    var m1b = 1;
+    module m1b { export var y = 2; } // error
+           ~~~
+!!! error TS2300: Duplicate identifier 'm1b'.
+    var m1b = 1; // error
         ~~~
 !!! error TS2300: Duplicate identifier 'm1b'.
     
@@ -26,7 +33,9 @@ tests/cases/compiler/augmentedTypesModules.ts(51,8): error TS2434: A module decl
     }
     var m1c = 1; // Should be allowed
     
-    module m1d {
+    module m1d { // error
+           ~~~
+!!! error TS2300: Duplicate identifier 'm1d'.
         export class I { foo() { } }
     }
     var m1d = 1; // error
diff --git a/tests/baselines/reference/augmentedTypesModules.js b/tests/baselines/reference/augmentedTypesModules.js
index 5085b1cbda3..0c7967b2227 100644
--- a/tests/baselines/reference/augmentedTypesModules.js
+++ b/tests/baselines/reference/augmentedTypesModules.js
@@ -3,18 +3,18 @@
 module m1 { }
 var m1 = 1; // Should be allowed
 
-module m1a { var y = 2; }
-var m1a = 1;
+module m1a { var y = 2; } // error
+var m1a = 1; // error
 
-module m1b { export var y = 2; }
-var m1b = 1;
+module m1b { export var y = 2; } // error
+var m1b = 1; // error
 
 module m1c {
     export interface I { foo(): void; }
 }
 var m1c = 1; // Should be allowed
 
-module m1d {
+module m1d { // error
     export class I { foo() { } }
 }
 var m1d = 1; // error
@@ -102,13 +102,13 @@ var m1 = 1; // Should be allowed
 var m1a;
 (function (m1a) {
     var y = 2;
-})(m1a || (m1a = {}));
-var m1a = 1;
+})(m1a || (m1a = {})); // error
+var m1a = 1; // error
 var m1b;
 (function (m1b) {
     m1b.y = 2;
-})(m1b || (m1b = {}));
-var m1b = 1;
+})(m1b || (m1b = {})); // error
+var m1b = 1; // error
 var m1c = 1; // Should be allowed
 var m1d;
 (function (m1d) {
diff --git a/tests/baselines/reference/augmentedTypesVar.errors.txt b/tests/baselines/reference/augmentedTypesVar.errors.txt
index 9f3980e39bc..24c194d25c3 100644
--- a/tests/baselines/reference/augmentedTypesVar.errors.txt
+++ b/tests/baselines/reference/augmentedTypesVar.errors.txt
@@ -1,41 +1,55 @@
+tests/cases/compiler/augmentedTypesVar.ts(6,5): error TS2300: Duplicate identifier 'x2'.
 tests/cases/compiler/augmentedTypesVar.ts(7,10): error TS2300: Duplicate identifier 'x2'.
 tests/cases/compiler/augmentedTypesVar.ts(10,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x3' must be of type 'number', but here has type '() => void'.
+tests/cases/compiler/augmentedTypesVar.ts(13,5): error TS2300: Duplicate identifier 'x4'.
 tests/cases/compiler/augmentedTypesVar.ts(14,7): error TS2300: Duplicate identifier 'x4'.
+tests/cases/compiler/augmentedTypesVar.ts(16,5): error TS2300: Duplicate identifier 'x4a'.
 tests/cases/compiler/augmentedTypesVar.ts(17,7): error TS2300: Duplicate identifier 'x4a'.
+tests/cases/compiler/augmentedTypesVar.ts(20,5): error TS2300: Duplicate identifier 'x5'.
 tests/cases/compiler/augmentedTypesVar.ts(21,6): error TS2300: Duplicate identifier 'x5'.
+tests/cases/compiler/augmentedTypesVar.ts(27,5): error TS2300: Duplicate identifier 'x6a'.
 tests/cases/compiler/augmentedTypesVar.ts(28,8): error TS2300: Duplicate identifier 'x6a'.
+tests/cases/compiler/augmentedTypesVar.ts(30,5): error TS2300: Duplicate identifier 'x6b'.
 tests/cases/compiler/augmentedTypesVar.ts(31,8): error TS2300: Duplicate identifier 'x6b'.
 
 
-==== tests/cases/compiler/augmentedTypesVar.ts (7 errors) ====
+==== tests/cases/compiler/augmentedTypesVar.ts (13 errors) ====
     // var then var
     var x1 = 1;
     var x1 = 2;
     
     // var then function
-    var x2 = 1;
-    function x2() { } // should be an error
+    var x2 = 1; // error
+        ~~
+!!! error TS2300: Duplicate identifier 'x2'.
+    function x2() { } // error
              ~~
 !!! error TS2300: Duplicate identifier 'x2'.
     
-    var x3 = 1;
-    var x3 = () => { } // should be an error
+    var x3 = 1; 
+    var x3 = () => { } // error
         ~~
 !!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x3' must be of type 'number', but here has type '() => void'.
     
     // var then class
-    var x4 = 1;
+    var x4 = 1; // error
+        ~~
+!!! error TS2300: Duplicate identifier 'x4'.
     class x4 { } // error
           ~~
 !!! error TS2300: Duplicate identifier 'x4'.
     
-    var x4a = 1;
+    var x4a = 1; // error
+        ~~~
+!!! error TS2300: Duplicate identifier 'x4a'.
     class x4a { public foo() { } } // error
           ~~~
 !!! error TS2300: Duplicate identifier 'x4a'.
     
     // var then enum
     var x5 = 1;
+        ~~
+!!! error TS2300: Duplicate identifier 'x5'.
     enum x5 { One } // error
          ~~
 !!! error TS2300: Duplicate identifier 'x5'.
@@ -44,12 +58,16 @@ tests/cases/compiler/augmentedTypesVar.ts(31,8): error TS2300: Duplicate identif
     var x6 = 1;
     module x6 { } // ok since non-instantiated
     
-    var x6a = 1;
+    var x6a = 1; // error
+        ~~~
+!!! error TS2300: Duplicate identifier 'x6a'.
     module x6a { var y = 2; } // error since instantiated
            ~~~
 !!! error TS2300: Duplicate identifier 'x6a'.
     
-    var x6b = 1;
+    var x6b = 1; // error
+        ~~~
+!!! error TS2300: Duplicate identifier 'x6b'.
     module x6b { export var y = 2; } // error
            ~~~
 !!! error TS2300: Duplicate identifier 'x6b'.
diff --git a/tests/baselines/reference/augmentedTypesVar.js b/tests/baselines/reference/augmentedTypesVar.js
index ca50b8ab9a9..4735d647056 100644
--- a/tests/baselines/reference/augmentedTypesVar.js
+++ b/tests/baselines/reference/augmentedTypesVar.js
@@ -4,17 +4,17 @@ var x1 = 1;
 var x1 = 2;
 
 // var then function
-var x2 = 1;
-function x2() { } // should be an error
+var x2 = 1; // error
+function x2() { } // error
 
-var x3 = 1;
-var x3 = () => { } // should be an error
+var x3 = 1; 
+var x3 = () => { } // error
 
 // var then class
-var x4 = 1;
+var x4 = 1; // error
 class x4 { } // error
 
-var x4a = 1;
+var x4a = 1; // error
 class x4a { public foo() { } } // error
 
 // var then enum
@@ -25,10 +25,10 @@ enum x5 { One } // error
 var x6 = 1;
 module x6 { } // ok since non-instantiated
 
-var x6a = 1;
+var x6a = 1; // error
 module x6a { var y = 2; } // error since instantiated
 
-var x6b = 1;
+var x6b = 1; // error
 module x6b { export var y = 2; } // error
 
 // var then import, messes with other error reporting
@@ -41,20 +41,20 @@ module x6b { export var y = 2; } // error
 var x1 = 1;
 var x1 = 2;
 // var then function
-var x2 = 1;
+var x2 = 1; // error
 function x2() {
-} // should be an error
+} // error
 var x3 = 1;
 var x3 = function () {
-}; // should be an error
+}; // error
 // var then class
-var x4 = 1;
+var x4 = 1; // error
 var x4 = (function () {
     function x4() {
     }
     return x4;
 })(); // error
-var x4a = 1;
+var x4a = 1; // error
 var x4a = (function () {
     function x4a() {
     }
@@ -70,12 +70,12 @@ var x5;
 })(x5 || (x5 = {})); // error
 // var then module
 var x6 = 1;
-var x6a = 1;
+var x6a = 1; // error
 var x6a;
 (function (x6a) {
     var y = 2;
 })(x6a || (x6a = {})); // error since instantiated
-var x6b = 1;
+var x6b = 1; // error
 var x6b;
 (function (x6b) {
     x6b.y = 2;
diff --git a/tests/baselines/reference/callOnInstance.errors.txt b/tests/baselines/reference/callOnInstance.errors.txt
index c1861d05377..156bdfd512a 100644
--- a/tests/baselines/reference/callOnInstance.errors.txt
+++ b/tests/baselines/reference/callOnInstance.errors.txt
@@ -1,13 +1,16 @@
+tests/cases/compiler/callOnInstance.ts(1,18): error TS2300: Duplicate identifier 'D'.
 tests/cases/compiler/callOnInstance.ts(3,15): error TS2300: Duplicate identifier 'D'.
 tests/cases/compiler/callOnInstance.ts(7,19): error TS2346: Supplied parameters do not match any signature of call target.
 tests/cases/compiler/callOnInstance.ts(7,19): error TS2350: Only a void function can be called with the 'new' keyword.
 tests/cases/compiler/callOnInstance.ts(10,1): error TS2349: Cannot invoke an expression whose type lacks a call signature.
 
 
-==== tests/cases/compiler/callOnInstance.ts (4 errors) ====
-    declare function D(): string;
+==== tests/cases/compiler/callOnInstance.ts (5 errors) ====
+    declare function D(): string; // error
+                     ~
+!!! error TS2300: Duplicate identifier 'D'.
     
-    declare class D { constructor (value: number); } // Duplicate identifier
+    declare class D { constructor (value: number); } // error
                   ~
 !!! error TS2300: Duplicate identifier 'D'.
     
diff --git a/tests/baselines/reference/callOnInstance.js b/tests/baselines/reference/callOnInstance.js
index 477bdca26a7..3b07d0affc8 100644
--- a/tests/baselines/reference/callOnInstance.js
+++ b/tests/baselines/reference/callOnInstance.js
@@ -1,7 +1,7 @@
 //// [callOnInstance.ts]
-declare function D(): string;
+declare function D(): string; // error
 
-declare class D { constructor (value: number); } // Duplicate identifier
+declare class D { constructor (value: number); } // error
 
 var s1: string = D(); // OK
 
diff --git a/tests/baselines/reference/callOverloads1.errors.txt b/tests/baselines/reference/callOverloads1.errors.txt
index 759c00aa7e4..64927462104 100644
--- a/tests/baselines/reference/callOverloads1.errors.txt
+++ b/tests/baselines/reference/callOverloads1.errors.txt
@@ -1,10 +1,13 @@
+tests/cases/compiler/callOverloads1.ts(1,7): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads1.ts(9,10): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads1.ts(9,10): error TS2391: Function implementation is missing or not immediately following the declaration.
 tests/cases/compiler/callOverloads1.ts(17,1): error TS2348: Value of type 'typeof Foo' is not callable. Did you mean to include 'new'?
 
 
-==== tests/cases/compiler/callOverloads1.ts (3 errors) ====
-    class Foo {    
+==== tests/cases/compiler/callOverloads1.ts (4 errors) ====
+    class Foo { // error
+          ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
         bar1() { /*WScript.Echo("bar1");*/ }
     
         constructor(x: any) {
diff --git a/tests/baselines/reference/callOverloads1.js b/tests/baselines/reference/callOverloads1.js
index dc76fcba98a..86cb951f853 100644
--- a/tests/baselines/reference/callOverloads1.js
+++ b/tests/baselines/reference/callOverloads1.js
@@ -1,5 +1,5 @@
 //// [callOverloads1.ts]
-class Foo {    
+class Foo { // error
     bar1() { /*WScript.Echo("bar1");*/ }
 
     constructor(x: any) {
diff --git a/tests/baselines/reference/callOverloads2.errors.txt b/tests/baselines/reference/callOverloads2.errors.txt
index 693b67872eb..6291fa8f3de 100644
--- a/tests/baselines/reference/callOverloads2.errors.txt
+++ b/tests/baselines/reference/callOverloads2.errors.txt
@@ -1,14 +1,18 @@
+tests/cases/compiler/callOverloads2.ts(3,7): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads2.ts(11,10): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads2.ts(13,10): error TS2389: Function implementation name must be 'Foo'.
-tests/cases/compiler/callOverloads2.ts(14,1): error TS2393: Duplicate function implementation.
+tests/cases/compiler/callOverloads2.ts(13,10): error TS2393: Duplicate function implementation.
+tests/cases/compiler/callOverloads2.ts(14,10): error TS2393: Duplicate function implementation.
 tests/cases/compiler/callOverloads2.ts(16,10): error TS2391: Function implementation is missing or not immediately following the declaration.
 tests/cases/compiler/callOverloads2.ts(24,1): error TS2348: Value of type 'typeof Foo' is not callable. Did you mean to include 'new'?
 
 
-==== tests/cases/compiler/callOverloads2.ts (5 errors) ====
+==== tests/cases/compiler/callOverloads2.ts (7 errors) ====
     
     
-    class Foo {    
+    class Foo { // error
+          ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
         bar1() { /*WScript.Echo("bar1");*/ }
     
         constructor(x: any) {
@@ -16,15 +20,17 @@ tests/cases/compiler/callOverloads2.ts(24,1): error TS2348: Value of type 'typeo
         }
     }
     
-    function Foo();
+    function Foo(); // error
              ~~~
 !!! error TS2300: Duplicate identifier 'Foo'.
     
-    function F1(s:string) {return s;}
+    function F1(s:string) {return s;} // error
              ~~
 !!! error TS2389: Function implementation name must be 'Foo'.
-    function F1(a:any) { return a;} // error -  duplicate identifier
-    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+             ~~
+!!! error TS2393: Duplicate function implementation.
+    function F1(a:any) { return a;} // error
+             ~~
 !!! error TS2393: Duplicate function implementation.
     
     function Goo(s:string); // error - no implementation
diff --git a/tests/baselines/reference/callOverloads2.js b/tests/baselines/reference/callOverloads2.js
index be42753bc3d..e3cbceb177a 100644
--- a/tests/baselines/reference/callOverloads2.js
+++ b/tests/baselines/reference/callOverloads2.js
@@ -1,7 +1,7 @@
 //// [callOverloads2.ts]
 
 
-class Foo {    
+class Foo { // error
     bar1() { /*WScript.Echo("bar1");*/ }
 
     constructor(x: any) {
@@ -9,10 +9,10 @@ class Foo {
     }
 }
 
-function Foo();
+function Foo(); // error
 
-function F1(s:string) {return s;}
-function F1(a:any) { return a;} // error -  duplicate identifier
+function F1(s:string) {return s;} // error
+function F1(a:any) { return a;} // error
 
 function Goo(s:string); // error - no implementation
 
@@ -36,10 +36,10 @@ var Foo = (function () {
 })();
 function F1(s) {
     return s;
-}
+} // error
 function F1(a) {
     return a;
-} // error -  duplicate identifier
+} // error
 var f1 = new Foo("hey");
 f1.bar1();
 Foo();
diff --git a/tests/baselines/reference/callOverloads3.errors.txt b/tests/baselines/reference/callOverloads3.errors.txt
index 986f0478369..ecb889bc1ab 100644
--- a/tests/baselines/reference/callOverloads3.errors.txt
+++ b/tests/baselines/reference/callOverloads3.errors.txt
@@ -1,21 +1,27 @@
+tests/cases/compiler/callOverloads3.ts(2,10): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads3.ts(2,16): error TS2304: Cannot find name 'Foo'.
+tests/cases/compiler/callOverloads3.ts(3,10): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads3.ts(3,10): error TS2391: Function implementation is missing or not immediately following the declaration.
 tests/cases/compiler/callOverloads3.ts(3,24): error TS2304: Cannot find name 'Foo'.
 tests/cases/compiler/callOverloads3.ts(4,7): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads3.ts(12,10): error TS2350: Only a void function can be called with the 'new' keyword.
 
 
-==== tests/cases/compiler/callOverloads3.ts (5 errors) ====
+==== tests/cases/compiler/callOverloads3.ts (7 errors) ====
     
-    function Foo():Foo;
+    function Foo():Foo; // error
+             ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
                    ~~~
 !!! error TS2304: Cannot find name 'Foo'.
-    function Foo(s:string):Foo;
+    function Foo(s:string):Foo; // error
+             ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
              ~~~
 !!! error TS2391: Function implementation is missing or not immediately following the declaration.
                            ~~~
 !!! error TS2304: Cannot find name 'Foo'.
-    class Foo {    
+    class Foo { // error
           ~~~
 !!! error TS2300: Duplicate identifier 'Foo'.
         bar1() { /*WScript.Echo("bar1");*/ }
diff --git a/tests/baselines/reference/callOverloads3.js b/tests/baselines/reference/callOverloads3.js
index 93176cc1edb..85c16fe85a6 100644
--- a/tests/baselines/reference/callOverloads3.js
+++ b/tests/baselines/reference/callOverloads3.js
@@ -1,8 +1,8 @@
 //// [callOverloads3.ts]
 
-function Foo():Foo;
-function Foo(s:string):Foo;
-class Foo {    
+function Foo():Foo; // error
+function Foo(s:string):Foo; // error
+class Foo { // error
     bar1() { /*WScript.Echo("bar1");*/ }
     constructor(x: any) {
         // WScript.Echo("Constructor function has executed");
diff --git a/tests/baselines/reference/callOverloads4.errors.txt b/tests/baselines/reference/callOverloads4.errors.txt
index cec3a1834ba..3010d7c15d8 100644
--- a/tests/baselines/reference/callOverloads4.errors.txt
+++ b/tests/baselines/reference/callOverloads4.errors.txt
@@ -1,21 +1,27 @@
+tests/cases/compiler/callOverloads4.ts(2,10): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads4.ts(2,16): error TS2304: Cannot find name 'Foo'.
+tests/cases/compiler/callOverloads4.ts(3,10): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads4.ts(3,10): error TS2391: Function implementation is missing or not immediately following the declaration.
 tests/cases/compiler/callOverloads4.ts(3,24): error TS2304: Cannot find name 'Foo'.
 tests/cases/compiler/callOverloads4.ts(4,7): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads4.ts(12,10): error TS2350: Only a void function can be called with the 'new' keyword.
 
 
-==== tests/cases/compiler/callOverloads4.ts (5 errors) ====
+==== tests/cases/compiler/callOverloads4.ts (7 errors) ====
     
-    function Foo():Foo;
+    function Foo():Foo; // error
+             ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
                    ~~~
 !!! error TS2304: Cannot find name 'Foo'.
-    function Foo(s:string):Foo;
+    function Foo(s:string):Foo; // error
+             ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
              ~~~
 !!! error TS2391: Function implementation is missing or not immediately following the declaration.
                            ~~~
 !!! error TS2304: Cannot find name 'Foo'.
-    class Foo {    
+    class Foo { // error
           ~~~
 !!! error TS2300: Duplicate identifier 'Foo'.
         bar1() { /*WScript.Echo("bar1");*/ }
diff --git a/tests/baselines/reference/callOverloads4.js b/tests/baselines/reference/callOverloads4.js
index 86ec2b91e7e..6aab555b721 100644
--- a/tests/baselines/reference/callOverloads4.js
+++ b/tests/baselines/reference/callOverloads4.js
@@ -1,8 +1,8 @@
 //// [callOverloads4.ts]
 
-function Foo():Foo;
-function Foo(s:string):Foo;
-class Foo {    
+function Foo():Foo; // error
+function Foo(s:string):Foo; // error
+class Foo { // error
     bar1() { /*WScript.Echo("bar1");*/ }
     constructor(s: string);
     constructor(x: any) {
diff --git a/tests/baselines/reference/callOverloads5.errors.txt b/tests/baselines/reference/callOverloads5.errors.txt
index 240e10b9f55..e521a9a9076 100644
--- a/tests/baselines/reference/callOverloads5.errors.txt
+++ b/tests/baselines/reference/callOverloads5.errors.txt
@@ -1,20 +1,26 @@
+tests/cases/compiler/callOverloads5.ts(1,10): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads5.ts(1,16): error TS2304: Cannot find name 'Foo'.
+tests/cases/compiler/callOverloads5.ts(2,10): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads5.ts(2,10): error TS2391: Function implementation is missing or not immediately following the declaration.
 tests/cases/compiler/callOverloads5.ts(2,24): error TS2304: Cannot find name 'Foo'.
 tests/cases/compiler/callOverloads5.ts(3,7): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/callOverloads5.ts(13,10): error TS2350: Only a void function can be called with the 'new' keyword.
 
 
-==== tests/cases/compiler/callOverloads5.ts (5 errors) ====
-    function Foo():Foo;
+==== tests/cases/compiler/callOverloads5.ts (7 errors) ====
+    function Foo():Foo; // error
+             ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
                    ~~~
 !!! error TS2304: Cannot find name 'Foo'.
-    function Foo(s:string):Foo;
+    function Foo(s:string):Foo; // error
+             ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
              ~~~
 !!! error TS2391: Function implementation is missing or not immediately following the declaration.
                            ~~~
 !!! error TS2304: Cannot find name 'Foo'.
-    class Foo {
+    class Foo { // error
           ~~~
 !!! error TS2300: Duplicate identifier 'Foo'.
     	bar1(s:string);
diff --git a/tests/baselines/reference/callOverloads5.js b/tests/baselines/reference/callOverloads5.js
index 30cc65915ec..2220568e4c2 100644
--- a/tests/baselines/reference/callOverloads5.js
+++ b/tests/baselines/reference/callOverloads5.js
@@ -1,7 +1,7 @@
 //// [callOverloads5.ts]
-function Foo():Foo;
-function Foo(s:string):Foo;
-class Foo {
+function Foo():Foo; // error
+function Foo(s:string):Foo; // error
+class Foo { // error
 	bar1(s:string);
 	bar1(n:number);
     bar1(a:any) { /*WScript.Echo(a);*/ }
diff --git a/tests/baselines/reference/callSignaturesWithDuplicateParameters.errors.txt b/tests/baselines/reference/callSignaturesWithDuplicateParameters.errors.txt
index ff1fd1e66cf..034aa4039cf 100644
--- a/tests/baselines/reference/callSignaturesWithDuplicateParameters.errors.txt
+++ b/tests/baselines/reference/callSignaturesWithDuplicateParameters.errors.txt
@@ -1,107 +1,173 @@
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(3,14): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(3,17): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(4,22): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(4,25): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(5,20): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(5,23): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(6,11): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(6,14): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(7,14): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(7,20): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(9,15): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(9,26): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(10,23): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(10,34): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(11,20): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(11,31): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(12,11): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(12,22): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(16,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(16,12): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(17,10): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(17,21): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(18,13): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(18,19): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(22,6): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(22,9): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(23,6): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(23,17): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(24,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(24,12): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(25,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(25,20): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(26,13): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(26,19): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(30,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(30,12): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(31,10): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(31,21): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(35,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(35,12): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(36,21): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(36,32): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(37,12): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts(37,18): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts (22 errors) ====
+==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithDuplicateParameters.ts (44 errors) ====
     // Duplicate parameter names are always an error
     
     function foo(x, x) { }
+                 ~
+!!! error TS2300: Duplicate identifier 'x'.
                     ~
 !!! error TS2300: Duplicate identifier 'x'.
     var f = function foo(x, x) { }
+                         ~
+!!! error TS2300: Duplicate identifier 'x'.
                             ~
 !!! error TS2300: Duplicate identifier 'x'.
     var f2 = function (x, x) { }
+                       ~
+!!! error TS2300: Duplicate identifier 'x'.
                           ~
 !!! error TS2300: Duplicate identifier 'x'.
     var f3 = (x, x) => { }
+              ~
+!!! error TS2300: Duplicate identifier 'x'.
                  ~
 !!! error TS2300: Duplicate identifier 'x'.
     var f4 = <T>(x: T, x: T) => { }
+                 ~
+!!! error TS2300: Duplicate identifier 'x'.
                        ~
 !!! error TS2300: Duplicate identifier 'x'.
     
     function foo2(x: string, x: number) { }
+                  ~
+!!! error TS2300: Duplicate identifier 'x'.
                              ~
 !!! error TS2300: Duplicate identifier 'x'.
     var f5 = function foo(x: string, x: number) { }
+                          ~
+!!! error TS2300: Duplicate identifier 'x'.
                                      ~
 !!! error TS2300: Duplicate identifier 'x'.
     var f6 = function (x: string, x: number) { }
+                       ~
+!!! error TS2300: Duplicate identifier 'x'.
                                   ~
 !!! error TS2300: Duplicate identifier 'x'.
     var f7 = (x: string, x: number) => { }
+              ~
+!!! error TS2300: Duplicate identifier 'x'.
                          ~
 !!! error TS2300: Duplicate identifier 'x'.
     var f8 = <T>(x: T, y: T) => { }
     
     class C {
         foo(x, x) { }
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
                ~
 !!! error TS2300: Duplicate identifier 'x'.
         foo2(x: number, x: string) { }
+             ~
+!!! error TS2300: Duplicate identifier 'x'.
                         ~
 !!! error TS2300: Duplicate identifier 'x'.
         foo3<T>(x: T, x: T) { }
+                ~
+!!! error TS2300: Duplicate identifier 'x'.
                       ~
 !!! error TS2300: Duplicate identifier 'x'.
     }
     
     interface I {
         (x, x);
+         ~
+!!! error TS2300: Duplicate identifier 'x'.
             ~
 !!! error TS2300: Duplicate identifier 'x'.
         (x: string, x: number);
+         ~
+!!! error TS2300: Duplicate identifier 'x'.
                     ~
 !!! error TS2300: Duplicate identifier 'x'.
         foo(x, x);
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
                ~
 !!! error TS2300: Duplicate identifier 'x'.
         foo(x: number, x: string);
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
                        ~
 !!! error TS2300: Duplicate identifier 'x'.
         foo3<T>(x: T, x: T);
+                ~
+!!! error TS2300: Duplicate identifier 'x'.
                       ~
 !!! error TS2300: Duplicate identifier 'x'.
     }
     
     var a: {
         foo(x, x);
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
                ~
 !!! error TS2300: Duplicate identifier 'x'.
         foo2(x: number, x: string);
+             ~
+!!! error TS2300: Duplicate identifier 'x'.
                         ~
 !!! error TS2300: Duplicate identifier 'x'.
     };
     
     var b = {
         foo(x, x) { },
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
                ~
 !!! error TS2300: Duplicate identifier 'x'.
         a: function foo(x: number, x: string) { },
+                        ~
+!!! error TS2300: Duplicate identifier 'x'.
                                    ~
 !!! error TS2300: Duplicate identifier 'x'.
         b: <T>(x: T, x: T) => { }
+               ~
+!!! error TS2300: Duplicate identifier 'x'.
                      ~
 !!! error TS2300: Duplicate identifier 'x'.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/callSignaturesWithParameterInitializers2.errors.txt b/tests/baselines/reference/callSignaturesWithParameterInitializers2.errors.txt
index fcc1eee9169..1801bd42e4d 100644
--- a/tests/baselines/reference/callSignaturesWithParameterInitializers2.errors.txt
+++ b/tests/baselines/reference/callSignaturesWithParameterInitializers2.errors.txt
@@ -1,10 +1,11 @@
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts(20,15): error TS1005: '{' expected.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts(4,14): error TS2371: A parameter initializer is only allowed in a function or constructor implementation.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts(11,9): error TS2371: A parameter initializer is only allowed in a function or constructor implementation.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts(20,5): error TS2300: Duplicate identifier 'foo'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts(21,5): error TS2300: Duplicate identifier 'foo'.
 
 
-==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts (4 errors) ====
+==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts (5 errors) ====
     // Optional parameters allow initializers only in implementation signatures
     // All the below declarations are errors
     
@@ -28,10 +29,12 @@ tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWit
     c.foo(1);
     
     var b = {
-        foo(x = 1),
+        foo(x = 1), // error
                   ~
 !!! error TS1005: '{' expected.
-        foo(x = 1) { },
+        ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
+        foo(x = 1) { }, // error
         ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
     }
diff --git a/tests/baselines/reference/class1.errors.txt b/tests/baselines/reference/class1.errors.txt
index 91d29d981c2..b90fae9cb40 100644
--- a/tests/baselines/reference/class1.errors.txt
+++ b/tests/baselines/reference/class1.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/class1.ts(1,11): error TS2300: Duplicate identifier 'foo'.
 tests/cases/compiler/class1.ts(2,7): error TS2300: Duplicate identifier 'foo'.
 
 
-==== tests/cases/compiler/class1.ts (1 errors) ====
-    interface foo{ }
-    class foo{ }
+==== tests/cases/compiler/class1.ts (2 errors) ====
+    interface foo{ } // error
+              ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
+    class foo{ } // error
           ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
\ No newline at end of file
diff --git a/tests/baselines/reference/class1.js b/tests/baselines/reference/class1.js
index 96b279e58c6..7a104e237b6 100644
--- a/tests/baselines/reference/class1.js
+++ b/tests/baselines/reference/class1.js
@@ -1,10 +1,10 @@
 //// [class1.ts]
-interface foo{ }
-class foo{ }
+interface foo{ } // error
+class foo{ } // error
 
 //// [class1.js]
 var foo = (function () {
     function foo() {
     }
     return foo;
-})();
+})(); // error
diff --git a/tests/baselines/reference/classAndInterface1.errors.txt b/tests/baselines/reference/classAndInterface1.errors.txt
index d497fb4c44e..8d31e847d71 100644
--- a/tests/baselines/reference/classAndInterface1.errors.txt
+++ b/tests/baselines/reference/classAndInterface1.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/classAndInterface1.ts(1,8): error TS2300: Duplicate identifier 'cli'.
 tests/cases/compiler/classAndInterface1.ts(2,11): error TS2300: Duplicate identifier 'cli'.
 
 
-==== tests/cases/compiler/classAndInterface1.ts (1 errors) ====
-    class cli { }
+==== tests/cases/compiler/classAndInterface1.ts (2 errors) ====
+     class cli { } // error
+           ~~~
+!!! error TS2300: Duplicate identifier 'cli'.
     interface cli { } // error
               ~~~
 !!! error TS2300: Duplicate identifier 'cli'.
\ No newline at end of file
diff --git a/tests/baselines/reference/classAndInterface1.js b/tests/baselines/reference/classAndInterface1.js
index 74eec3e942e..5efabded838 100644
--- a/tests/baselines/reference/classAndInterface1.js
+++ b/tests/baselines/reference/classAndInterface1.js
@@ -1,5 +1,5 @@
 //// [classAndInterface1.ts]
-class cli { }
+ class cli { } // error
 interface cli { } // error
 
 //// [classAndInterface1.js]
@@ -7,4 +7,4 @@ var cli = (function () {
     function cli() {
     }
     return cli;
-})();
+})(); // error
diff --git a/tests/baselines/reference/classAndInterfaceWithSameName.errors.txt b/tests/baselines/reference/classAndInterfaceWithSameName.errors.txt
index a92f31ef469..aa3e687cf4d 100644
--- a/tests/baselines/reference/classAndInterfaceWithSameName.errors.txt
+++ b/tests/baselines/reference/classAndInterfaceWithSameName.errors.txt
@@ -1,15 +1,21 @@
+tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(1,7): error TS2300: Duplicate identifier 'C'.
 tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(2,11): error TS2300: Duplicate identifier 'C'.
+tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(5,11): error TS2300: Duplicate identifier 'D'.
 tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(9,15): error TS2300: Duplicate identifier 'D'.
 
 
-==== tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts (2 errors) ====
+==== tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts (4 errors) ====
     class C { foo: string; }
+          ~
+!!! error TS2300: Duplicate identifier 'C'.
     interface C { foo: string; } // error
               ~
 !!! error TS2300: Duplicate identifier 'C'.
     
     module M {
         class D {
+              ~
+!!! error TS2300: Duplicate identifier 'D'.
             bar: string;
         }
     
diff --git a/tests/baselines/reference/classAndVariableWithSameName.errors.txt b/tests/baselines/reference/classAndVariableWithSameName.errors.txt
index fb8b7e2dcde..2e8c16d4494 100644
--- a/tests/baselines/reference/classAndVariableWithSameName.errors.txt
+++ b/tests/baselines/reference/classAndVariableWithSameName.errors.txt
@@ -1,15 +1,21 @@
+tests/cases/conformance/classes/classDeclarations/classAndVariableWithSameName.ts(1,7): error TS2300: Duplicate identifier 'C'.
 tests/cases/conformance/classes/classDeclarations/classAndVariableWithSameName.ts(2,5): error TS2300: Duplicate identifier 'C'.
+tests/cases/conformance/classes/classDeclarations/classAndVariableWithSameName.ts(5,11): error TS2300: Duplicate identifier 'D'.
 tests/cases/conformance/classes/classDeclarations/classAndVariableWithSameName.ts(9,9): error TS2300: Duplicate identifier 'D'.
 
 
-==== tests/cases/conformance/classes/classDeclarations/classAndVariableWithSameName.ts (2 errors) ====
-    class C { foo: string; }
+==== tests/cases/conformance/classes/classDeclarations/classAndVariableWithSameName.ts (4 errors) ====
+    class C { foo: string; } // error
+          ~
+!!! error TS2300: Duplicate identifier 'C'.
     var C = ''; // error
         ~
 !!! error TS2300: Duplicate identifier 'C'.
     
     module M {
-        class D {
+        class D { // error
+              ~
+!!! error TS2300: Duplicate identifier 'D'.
             bar: string;
         }
     
diff --git a/tests/baselines/reference/classAndVariableWithSameName.js b/tests/baselines/reference/classAndVariableWithSameName.js
index ab17905d5b2..1d547dc5508 100644
--- a/tests/baselines/reference/classAndVariableWithSameName.js
+++ b/tests/baselines/reference/classAndVariableWithSameName.js
@@ -1,9 +1,9 @@
 //// [classAndVariableWithSameName.ts]
-class C { foo: string; }
+class C { foo: string; } // error
 var C = ''; // error
 
 module M {
-    class D {
+    class D { // error
         bar: string;
     }
 
@@ -15,7 +15,7 @@ var C = (function () {
     function C() {
     }
     return C;
-})();
+})(); // error
 var C = ''; // error
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/classCannotExtendVar.errors.txt b/tests/baselines/reference/classCannotExtendVar.errors.txt
index deed94615ce..5af07801bb4 100644
--- a/tests/baselines/reference/classCannotExtendVar.errors.txt
+++ b/tests/baselines/reference/classCannotExtendVar.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/classCannotExtendVar.ts(1,5): error TS2300: Duplicate identifier 'Markup'.
 tests/cases/compiler/classCannotExtendVar.ts(3,7): error TS2300: Duplicate identifier 'Markup'.
 
 
-==== tests/cases/compiler/classCannotExtendVar.ts (1 errors) ====
+==== tests/cases/compiler/classCannotExtendVar.ts (2 errors) ====
     var Markup;
+        ~~~~~~
+!!! error TS2300: Duplicate identifier 'Markup'.
     
     class Markup {
           ~~~~~~
diff --git a/tests/baselines/reference/classOverloadForFunction.errors.txt b/tests/baselines/reference/classOverloadForFunction.errors.txt
index 41f960dba66..14bc27fb5ca 100644
--- a/tests/baselines/reference/classOverloadForFunction.errors.txt
+++ b/tests/baselines/reference/classOverloadForFunction.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/classOverloadForFunction.ts(1,7): error TS2300: Duplicate identifier 'foo'.
 tests/cases/compiler/classOverloadForFunction.ts(2,10): error TS2300: Duplicate identifier 'foo'.
 
 
-==== tests/cases/compiler/classOverloadForFunction.ts (1 errors) ====
+==== tests/cases/compiler/classOverloadForFunction.ts (2 errors) ====
     class foo { };
+          ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
     function foo() {}
              ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
diff --git a/tests/baselines/reference/classOverloadForFunction2.errors.txt b/tests/baselines/reference/classOverloadForFunction2.errors.txt
index df635f10129..4dd459c48ec 100644
--- a/tests/baselines/reference/classOverloadForFunction2.errors.txt
+++ b/tests/baselines/reference/classOverloadForFunction2.errors.txt
@@ -1,10 +1,13 @@
+tests/cases/compiler/classOverloadForFunction2.ts(1,10): error TS2300: Duplicate identifier 'bar'.
 tests/cases/compiler/classOverloadForFunction2.ts(1,10): error TS2391: Function implementation is missing or not immediately following the declaration.
 tests/cases/compiler/classOverloadForFunction2.ts(2,7): error TS2300: Duplicate identifier 'bar'.
 
 
-==== tests/cases/compiler/classOverloadForFunction2.ts (2 errors) ====
+==== tests/cases/compiler/classOverloadForFunction2.ts (3 errors) ====
     function bar(): string;
              ~~~
+!!! error TS2300: Duplicate identifier 'bar'.
+             ~~~
 !!! error TS2391: Function implementation is missing or not immediately following the declaration.
     class bar {}
           ~~~
diff --git a/tests/baselines/reference/classWithTwoConstructorDefinitions.errors.txt b/tests/baselines/reference/classWithTwoConstructorDefinitions.errors.txt
index 6df51d85be3..6b08be330a0 100644
--- a/tests/baselines/reference/classWithTwoConstructorDefinitions.errors.txt
+++ b/tests/baselines/reference/classWithTwoConstructorDefinitions.errors.txt
@@ -1,17 +1,23 @@
+tests/cases/conformance/classes/constructorDeclarations/classWithTwoConstructorDefinitions.ts(2,5): error TS2392: Multiple constructor implementations are not allowed.
 tests/cases/conformance/classes/constructorDeclarations/classWithTwoConstructorDefinitions.ts(3,5): error TS2392: Multiple constructor implementations are not allowed.
+tests/cases/conformance/classes/constructorDeclarations/classWithTwoConstructorDefinitions.ts(7,5): error TS2392: Multiple constructor implementations are not allowed.
 tests/cases/conformance/classes/constructorDeclarations/classWithTwoConstructorDefinitions.ts(8,5): error TS2392: Multiple constructor implementations are not allowed.
 
 
-==== tests/cases/conformance/classes/constructorDeclarations/classWithTwoConstructorDefinitions.ts (2 errors) ====
+==== tests/cases/conformance/classes/constructorDeclarations/classWithTwoConstructorDefinitions.ts (4 errors) ====
     class C {
-        constructor() { }
+        constructor() { } // error
+        ~~~~~~~~~~~~~~~~~
+!!! error TS2392: Multiple constructor implementations are not allowed.
         constructor(x) { } // error
         ~~~~~~~~~~~~~~~~~~
 !!! error TS2392: Multiple constructor implementations are not allowed.
     }
     
     class D<T> {
-        constructor(x: T) { }
+        constructor(x: T) { } // error
+        ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2392: Multiple constructor implementations are not allowed.
         constructor(x: T, y: T) { } // error
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2392: Multiple constructor implementations are not allowed.
diff --git a/tests/baselines/reference/classWithTwoConstructorDefinitions.js b/tests/baselines/reference/classWithTwoConstructorDefinitions.js
index 77c98697f1f..31e5498cfc9 100644
--- a/tests/baselines/reference/classWithTwoConstructorDefinitions.js
+++ b/tests/baselines/reference/classWithTwoConstructorDefinitions.js
@@ -1,22 +1,22 @@
 //// [classWithTwoConstructorDefinitions.ts]
 class C {
-    constructor() { }
+    constructor() { } // error
     constructor(x) { } // error
 }
 
 class D<T> {
-    constructor(x: T) { }
+    constructor(x: T) { } // error
     constructor(x: T, y: T) { } // error
 }
 
 //// [classWithTwoConstructorDefinitions.js]
 var C = (function () {
     function C() {
-    }
+    } // error
     return C;
 })();
 var D = (function () {
     function D(x) {
-    }
+    } // error
     return D;
 })();
diff --git a/tests/baselines/reference/clinterfaces.errors.txt b/tests/baselines/reference/clinterfaces.errors.txt
index 62e8fc08725..d5eab2c7994 100644
--- a/tests/baselines/reference/clinterfaces.errors.txt
+++ b/tests/baselines/reference/clinterfaces.errors.txt
@@ -1,22 +1,32 @@
+tests/cases/compiler/clinterfaces.ts(2,11): error TS2300: Duplicate identifier 'C'.
 tests/cases/compiler/clinterfaces.ts(3,15): error TS2300: Duplicate identifier 'C'.
+tests/cases/compiler/clinterfaces.ts(4,15): error TS2300: Duplicate identifier 'D'.
 tests/cases/compiler/clinterfaces.ts(5,11): error TS2300: Duplicate identifier 'D'.
+tests/cases/compiler/clinterfaces.ts(8,11): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/clinterfaces.ts(12,7): error TS2300: Duplicate identifier 'Foo'.
+tests/cases/compiler/clinterfaces.ts(16,7): error TS2300: Duplicate identifier 'Bar'.
 tests/cases/compiler/clinterfaces.ts(20,11): error TS2300: Duplicate identifier 'Bar'.
 
 
-==== tests/cases/compiler/clinterfaces.ts (4 errors) ====
+==== tests/cases/compiler/clinterfaces.ts (8 errors) ====
     module M {
         class C { }
+              ~
+!!! error TS2300: Duplicate identifier 'C'.
         interface C { }
                   ~
 !!! error TS2300: Duplicate identifier 'C'.
         interface D { }
+                  ~
+!!! error TS2300: Duplicate identifier 'D'.
         class D { }
               ~
 !!! error TS2300: Duplicate identifier 'D'.
     }
     
     interface Foo<T> {
+              ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
         a: string;
     }
     
@@ -27,6 +37,8 @@ tests/cases/compiler/clinterfaces.ts(20,11): error TS2300: Duplicate identifier
     }
     
     class Bar<T>{
+          ~~~
+!!! error TS2300: Duplicate identifier 'Bar'.
         b: number;
     }
     
diff --git a/tests/baselines/reference/cloduleWithDuplicateMember1.errors.txt b/tests/baselines/reference/cloduleWithDuplicateMember1.errors.txt
index 7893afce829..914088f6c19 100644
--- a/tests/baselines/reference/cloduleWithDuplicateMember1.errors.txt
+++ b/tests/baselines/reference/cloduleWithDuplicateMember1.errors.txt
@@ -1,11 +1,13 @@
 tests/cases/compiler/cloduleWithDuplicateMember1.ts(2,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/cloduleWithDuplicateMember1.ts(3,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/compiler/cloduleWithDuplicateMember1.ts(3,16): error TS2300: Duplicate identifier 'x'.
+tests/cases/compiler/cloduleWithDuplicateMember1.ts(6,12): error TS2300: Duplicate identifier 'foo'.
 tests/cases/compiler/cloduleWithDuplicateMember1.ts(10,16): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/cloduleWithDuplicateMember1.ts(13,21): error TS2300: Duplicate identifier 'foo'.
 tests/cases/compiler/cloduleWithDuplicateMember1.ts(14,21): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/compiler/cloduleWithDuplicateMember1.ts (5 errors) ====
+==== tests/cases/compiler/cloduleWithDuplicateMember1.ts (7 errors) ====
     class C {
         get x() { return 1; }
             ~
@@ -13,9 +15,13 @@ tests/cases/compiler/cloduleWithDuplicateMember1.ts(14,21): error TS2300: Duplic
         static get x() {
                    ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+                   ~
+!!! error TS2300: Duplicate identifier 'x'.
             return '';
         }
         static foo() { }
+               ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
     }
     
     module C {
diff --git a/tests/baselines/reference/cloduleWithDuplicateMember2.errors.txt b/tests/baselines/reference/cloduleWithDuplicateMember2.errors.txt
index 1118f23a98d..55d2fdbddf2 100644
--- a/tests/baselines/reference/cloduleWithDuplicateMember2.errors.txt
+++ b/tests/baselines/reference/cloduleWithDuplicateMember2.errors.txt
@@ -1,9 +1,10 @@
 tests/cases/compiler/cloduleWithDuplicateMember2.ts(2,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/cloduleWithDuplicateMember2.ts(3,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/compiler/cloduleWithDuplicateMember2.ts(7,16): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/cloduleWithDuplicateMember2.ts(10,21): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/compiler/cloduleWithDuplicateMember2.ts (3 errors) ====
+==== tests/cases/compiler/cloduleWithDuplicateMember2.ts (4 errors) ====
     class C {
         set x(y) { }
             ~
@@ -15,6 +16,8 @@ tests/cases/compiler/cloduleWithDuplicateMember2.ts(10,21): error TS2300: Duplic
     
     module C {
         export var x = 1;
+                   ~
+!!! error TS2300: Duplicate identifier 'x'.
     }
     module C {
         export function x() { }
diff --git a/tests/baselines/reference/conflictingTypeAnnotatedVar.errors.txt b/tests/baselines/reference/conflictingTypeAnnotatedVar.errors.txt
index f1e7d2abeed..0b667108b5f 100644
--- a/tests/baselines/reference/conflictingTypeAnnotatedVar.errors.txt
+++ b/tests/baselines/reference/conflictingTypeAnnotatedVar.errors.txt
@@ -1,11 +1,14 @@
+tests/cases/compiler/conflictingTypeAnnotatedVar.ts(1,5): error TS2300: Duplicate identifier 'foo'.
 tests/cases/compiler/conflictingTypeAnnotatedVar.ts(2,10): error TS2300: Duplicate identifier 'foo'.
 tests/cases/compiler/conflictingTypeAnnotatedVar.ts(2,17): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value or consist of a single 'throw' statement.
 tests/cases/compiler/conflictingTypeAnnotatedVar.ts(3,10): error TS2300: Duplicate identifier 'foo'.
 tests/cases/compiler/conflictingTypeAnnotatedVar.ts(3,17): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value or consist of a single 'throw' statement.
 
 
-==== tests/cases/compiler/conflictingTypeAnnotatedVar.ts (4 errors) ====
+==== tests/cases/compiler/conflictingTypeAnnotatedVar.ts (5 errors) ====
     var foo: string;
+        ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
     function foo(): number { }
              ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
diff --git a/tests/baselines/reference/constructSignatureWithAccessibilityModifiersOnParameters2.errors.txt b/tests/baselines/reference/constructSignatureWithAccessibilityModifiersOnParameters2.errors.txt
index d17f52e90c1..e12f3a59ca1 100644
--- a/tests/baselines/reference/constructSignatureWithAccessibilityModifiersOnParameters2.errors.txt
+++ b/tests/baselines/reference/constructSignatureWithAccessibilityModifiersOnParameters2.errors.txt
@@ -1,8 +1,11 @@
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(4,17): error TS2369: A parameter property is only allowed in a constructor implementation.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(4,24): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(4,27): error TS2369: A parameter property is only allowed in a constructor implementation.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(4,35): error TS2300: Duplicate identifier 'y'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(5,24): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(5,35): error TS2300: Duplicate identifier 'y'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(9,17): error TS2369: A parameter property is only allowed in a constructor implementation.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(9,25): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(10,24): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(14,17): error TS2369: A parameter property is only allowed in a constructor implementation.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(19,10): error TS2369: A parameter property is only allowed in a constructor implementation.
@@ -15,15 +18,19 @@ tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatur
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts(35,10): error TS2369: A parameter property is only allowed in a constructor implementation.
 
 
-==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts (15 errors) ====
+==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters2.ts (18 errors) ====
     // Parameter properties are not valid in overloads of constructors
     
     class C {
         constructor(public x, private y);
                     ~~~~~~~~
 !!! error TS2369: A parameter property is only allowed in a constructor implementation.
+                           ~
+!!! error TS2300: Duplicate identifier 'x'.
                               ~~~~~~~~~
 !!! error TS2369: A parameter property is only allowed in a constructor implementation.
+                                      ~
+!!! error TS2300: Duplicate identifier 'y'.
         constructor(public x, private y) { }
                            ~
 !!! error TS2300: Duplicate identifier 'x'.
@@ -35,6 +42,8 @@ tests/cases/conformance/types/objectTypeLiteral/callSignatures/constructSignatur
         constructor(private x);
                     ~~~~~~~~~
 !!! error TS2369: A parameter property is only allowed in a constructor implementation.
+                            ~
+!!! error TS2300: Duplicate identifier 'x'.
         constructor(public x) { }
                            ~
 !!! error TS2300: Duplicate identifier 'x'.
diff --git a/tests/baselines/reference/constructorOverloads1.errors.txt b/tests/baselines/reference/constructorOverloads1.errors.txt
index 4b57d5c7839..d72aac5bcd0 100644
--- a/tests/baselines/reference/constructorOverloads1.errors.txt
+++ b/tests/baselines/reference/constructorOverloads1.errors.txt
@@ -1,15 +1,26 @@
+tests/cases/compiler/constructorOverloads1.ts(2,5): error TS2392: Multiple constructor implementations are not allowed.
+tests/cases/compiler/constructorOverloads1.ts(3,5): error TS2392: Multiple constructor implementations are not allowed.
+tests/cases/compiler/constructorOverloads1.ts(4,5): error TS2392: Multiple constructor implementations are not allowed.
 tests/cases/compiler/constructorOverloads1.ts(7,5): error TS2392: Multiple constructor implementations are not allowed.
 tests/cases/compiler/constructorOverloads1.ts(16,18): error TS2345: Argument of type 'Foo' is not assignable to parameter of type 'number'.
 tests/cases/compiler/constructorOverloads1.ts(17,18): error TS2345: Argument of type 'unknown[]' is not assignable to parameter of type 'number'.
 
 
-==== tests/cases/compiler/constructorOverloads1.ts (3 errors) ====
+==== tests/cases/compiler/constructorOverloads1.ts (6 errors) ====
     class Foo {
         constructor(s: string);
+        ~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2392: Multiple constructor implementations are not allowed.
         constructor(n: number);
+        ~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2392: Multiple constructor implementations are not allowed.
         constructor(x: any) {
+        ~~~~~~~~~~~~~~~~~~~~~
+    
     
         }
+    ~~~~~
+!!! error TS2392: Multiple constructor implementations are not allowed.
         constructor(x: any) {
         ~~~~~~~~~~~~~~~~~~~~~
     
diff --git a/tests/baselines/reference/constructorOverloads4.errors.txt b/tests/baselines/reference/constructorOverloads4.errors.txt
index 4b272b3f264..d2cc5ecd65b 100644
--- a/tests/baselines/reference/constructorOverloads4.errors.txt
+++ b/tests/baselines/reference/constructorOverloads4.errors.txt
@@ -1,12 +1,15 @@
+tests/cases/compiler/constructorOverloads4.ts(2,18): error TS2300: Duplicate identifier 'Function'.
 tests/cases/compiler/constructorOverloads4.ts(5,21): error TS2300: Duplicate identifier 'Function'.
 tests/cases/compiler/constructorOverloads4.ts(6,21): error TS2300: Duplicate identifier 'Function'.
 tests/cases/compiler/constructorOverloads4.ts(10,1): error TS2349: Cannot invoke an expression whose type lacks a call signature.
 tests/cases/compiler/constructorOverloads4.ts(11,1): error TS2348: Value of type 'typeof Function' is not callable. Did you mean to include 'new'?
 
 
-==== tests/cases/compiler/constructorOverloads4.ts (4 errors) ====
+==== tests/cases/compiler/constructorOverloads4.ts (5 errors) ====
     declare module M {    
         export class Function {
+                     ~~~~~~~~
+!!! error TS2300: Duplicate identifier 'Function'.
             constructor(...args: string[]);
         }
         export function Function(...args: any[]): any;
diff --git a/tests/baselines/reference/constructorOverloads5.errors.txt b/tests/baselines/reference/constructorOverloads5.errors.txt
index dd7ec956eac..0a695fc001c 100644
--- a/tests/baselines/reference/constructorOverloads5.errors.txt
+++ b/tests/baselines/reference/constructorOverloads5.errors.txt
@@ -1,12 +1,18 @@
+tests/cases/compiler/constructorOverloads5.ts(4,21): error TS2300: Duplicate identifier 'RegExp'.
+tests/cases/compiler/constructorOverloads5.ts(5,21): error TS2300: Duplicate identifier 'RegExp'.
 tests/cases/compiler/constructorOverloads5.ts(6,18): error TS2300: Duplicate identifier 'RegExp'.
 
 
-==== tests/cases/compiler/constructorOverloads5.ts (1 errors) ====
+==== tests/cases/compiler/constructorOverloads5.ts (3 errors) ====
      interface IArguments {}
     
      declare module M {
         export function RegExp(pattern: string): RegExp;
+                        ~~~~~~
+!!! error TS2300: Duplicate identifier 'RegExp'.
         export function RegExp(pattern: string, flags: string): RegExp;
+                        ~~~~~~
+!!! error TS2300: Duplicate identifier 'RegExp'.
         export class RegExp {
                      ~~~~~~
 !!! error TS2300: Duplicate identifier 'RegExp'.
diff --git a/tests/baselines/reference/constructorOverloads7.errors.txt b/tests/baselines/reference/constructorOverloads7.errors.txt
index 4caa358e7bd..e3409dbb399 100644
--- a/tests/baselines/reference/constructorOverloads7.errors.txt
+++ b/tests/baselines/reference/constructorOverloads7.errors.txt
@@ -1,9 +1,12 @@
+tests/cases/compiler/constructorOverloads7.ts(1,15): error TS2300: Duplicate identifier 'Point'.
 tests/cases/compiler/constructorOverloads7.ts(15,10): error TS2300: Duplicate identifier 'Point'.
 tests/cases/compiler/constructorOverloads7.ts(22,18): error TS2384: Overload signatures must all be ambient or non-ambient.
 
 
-==== tests/cases/compiler/constructorOverloads7.ts (2 errors) ====
+==== tests/cases/compiler/constructorOverloads7.ts (3 errors) ====
     declare class Point
+                  ~~~~~
+!!! error TS2300: Duplicate identifier 'Point'.
     {
         x: number;
         y: number;
diff --git a/tests/baselines/reference/constructorOverloads8.errors.txt b/tests/baselines/reference/constructorOverloads8.errors.txt
index 3aa7e509898..ca79964ad3f 100644
--- a/tests/baselines/reference/constructorOverloads8.errors.txt
+++ b/tests/baselines/reference/constructorOverloads8.errors.txt
@@ -1,9 +1,12 @@
+tests/cases/compiler/constructorOverloads8.ts(2,5): error TS2392: Multiple constructor implementations are not allowed.
 tests/cases/compiler/constructorOverloads8.ts(3,5): error TS2392: Multiple constructor implementations are not allowed.
 
 
-==== tests/cases/compiler/constructorOverloads8.ts (1 errors) ====
+==== tests/cases/compiler/constructorOverloads8.ts (2 errors) ====
     class C {
         constructor(x) { }
+        ~~~~~~~~~~~~~~~~~~
+!!! error TS2392: Multiple constructor implementations are not allowed.
         constructor(y, x) { } // illegal, 2 constructor implementations
         ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2392: Multiple constructor implementations are not allowed.
diff --git a/tests/baselines/reference/constructorParameterProperties2.errors.txt b/tests/baselines/reference/constructorParameterProperties2.errors.txt
index df759fbe709..42df015bc5b 100644
--- a/tests/baselines/reference/constructorParameterProperties2.errors.txt
+++ b/tests/baselines/reference/constructorParameterProperties2.errors.txt
@@ -1,9 +1,12 @@
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(10,5): error TS2300: Duplicate identifier 'y'.
 tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(11,24): error TS2300: Duplicate identifier 'y'.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts(18,5): 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(26,5): 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 (3 errors) ====
+==== tests/cases/conformance/classes/constructorDeclarations/constructorParameters/constructorParameterProperties2.ts (6 errors) ====
     class C {
         y: number;
         constructor(y: number) { } // ok
@@ -14,6 +17,8 @@ tests/cases/conformance/classes/constructorDeclarations/constructorParameters/co
     
     class D {
         y: number;
+        ~
+!!! error TS2300: Duplicate identifier 'y'.
         constructor(public y: number) { } // error
                            ~
 !!! error TS2300: Duplicate identifier 'y'.
@@ -24,6 +29,8 @@ tests/cases/conformance/classes/constructorDeclarations/constructorParameters/co
     
     class E {
         y: number;
+        ~
+!!! error TS2300: Duplicate identifier 'y'.
         constructor(private y: number) { } // error
                             ~
 !!! error TS2300: Duplicate identifier 'y'.
@@ -34,6 +41,8 @@ tests/cases/conformance/classes/constructorDeclarations/constructorParameters/co
     
     class F {
         y: number;
+        ~
+!!! error TS2300: Duplicate identifier 'y'.
         constructor(protected y: number) { } // error
                               ~
 !!! error TS2300: Duplicate identifier 'y'.
diff --git a/tests/baselines/reference/contextualTyping.errors.txt b/tests/baselines/reference/contextualTyping.errors.txt
index cea075477ee..ed6e50c1dbd 100644
--- a/tests/baselines/reference/contextualTyping.errors.txt
+++ b/tests/baselines/reference/contextualTyping.errors.txt
@@ -1,9 +1,10 @@
 tests/cases/compiler/contextualTyping.ts(189,18): error TS2384: Overload signatures must all be ambient or non-ambient.
+tests/cases/compiler/contextualTyping.ts(197,15): error TS2300: Duplicate identifier 'Point'.
 tests/cases/compiler/contextualTyping.ts(207,10): error TS2300: Duplicate identifier 'Point'.
 tests/cases/compiler/contextualTyping.ts(230,5): error TS2322: Type '{}' is not assignable to type 'B':\n  Property 'x' is missing in type '{}'.
 
 
-==== tests/cases/compiler/contextualTyping.ts (3 errors) ====
+==== tests/cases/compiler/contextualTyping.ts (4 errors) ====
     // DEFAULT INTERFACES
     interface IFoo {
         n: number;
@@ -203,6 +204,8 @@ tests/cases/compiler/contextualTyping.ts(230,5): error TS2322: Type '{}' is not
     
     // contextually typing from ambient class declarations
     declare class Point
+                  ~~~~~
+!!! error TS2300: Duplicate identifier 'Point'.
     {
           constructor(x: number, y: number);
           x: number;
diff --git a/tests/baselines/reference/declInput.errors.txt b/tests/baselines/reference/declInput.errors.txt
index 2fbaf6db6bc..8ec341ce15b 100644
--- a/tests/baselines/reference/declInput.errors.txt
+++ b/tests/baselines/reference/declInput.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/declInput.ts(1,11): error TS2300: Duplicate identifier 'bar'.
 tests/cases/compiler/declInput.ts(5,7): error TS2300: Duplicate identifier 'bar'.
 
 
-==== tests/cases/compiler/declInput.ts (1 errors) ====
+==== tests/cases/compiler/declInput.ts (2 errors) ====
     interface bar {
+              ~~~
+!!! error TS2300: Duplicate identifier 'bar'.
     
     }
     
diff --git a/tests/baselines/reference/derivedInterfaceIncompatibleWithBaseIndexer.errors.txt b/tests/baselines/reference/derivedInterfaceIncompatibleWithBaseIndexer.errors.txt
index a2e81b0eb95..7212121e106 100644
--- a/tests/baselines/reference/derivedInterfaceIncompatibleWithBaseIndexer.errors.txt
+++ b/tests/baselines/reference/derivedInterfaceIncompatibleWithBaseIndexer.errors.txt
@@ -4,11 +4,12 @@ tests/cases/conformance/interfaces/interfaceDeclarations/derivedInterfaceIncompa
 tests/cases/conformance/interfaces/interfaceDeclarations/derivedInterfaceIncompatibleWithBaseIndexer.ts(11,5): error TS2412: Property ''1'' of type '{ y: number; }' is not assignable to numeric index type '{ x: number; y: number; }'.
 tests/cases/conformance/interfaces/interfaceDeclarations/derivedInterfaceIncompatibleWithBaseIndexer.ts(15,5): error TS2411: Property 'foo' of type '{ y: number; }' is not assignable to string index type '{ x: number; }'.
 tests/cases/conformance/interfaces/interfaceDeclarations/derivedInterfaceIncompatibleWithBaseIndexer.ts(19,5): error TS2411: Property 'foo' of type '() => { x: number; }' is not assignable to string index type '{ x: number; }'.
+tests/cases/conformance/interfaces/interfaceDeclarations/derivedInterfaceIncompatibleWithBaseIndexer.ts(24,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/interfaces/interfaceDeclarations/derivedInterfaceIncompatibleWithBaseIndexer.ts(24,5): error TS2412: Property '1' of type '{ x: number; }' is not assignable to numeric index type '{ x: number; y: number; }'.
 tests/cases/conformance/interfaces/interfaceDeclarations/derivedInterfaceIncompatibleWithBaseIndexer.ts(28,5): error TS2300: Duplicate identifier ''1''.
 
 
-==== tests/cases/conformance/interfaces/interfaceDeclarations/derivedInterfaceIncompatibleWithBaseIndexer.ts (8 errors) ====
+==== tests/cases/conformance/interfaces/interfaceDeclarations/derivedInterfaceIncompatibleWithBaseIndexer.ts (9 errors) ====
     interface Base {
         [x: number]: { x: number; y: number; };
         [x: string]: { x: number; }
@@ -45,6 +46,8 @@ tests/cases/conformance/interfaces/interfaceDeclarations/derivedInterfaceIncompa
     // satisifies string indexer but not numeric indexer
     interface Derived5 extends Base {
         1: { x: number } // error
+        ~
+!!! error TS2300: Duplicate identifier '1'.
         ~~~~~~~~~~~~~~~~
 !!! error TS2412: Property '1' of type '{ x: number; }' is not assignable to numeric index type '{ x: number; y: number; }'.
     }
diff --git a/tests/baselines/reference/duplicateClassElements.errors.txt b/tests/baselines/reference/duplicateClassElements.errors.txt
index 9ff44679e44..004e68314fd 100644
--- a/tests/baselines/reference/duplicateClassElements.errors.txt
+++ b/tests/baselines/reference/duplicateClassElements.errors.txt
@@ -8,30 +8,43 @@ tests/cases/compiler/duplicateClassElements.ts(29,9): error TS1056: Accessors ar
 tests/cases/compiler/duplicateClassElements.ts(32,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/duplicateClassElements.ts(36,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/duplicateClassElements.ts(39,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/compiler/duplicateClassElements.ts(2,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/duplicateClassElements.ts(3,12): error TS2300: Duplicate identifier 'a'.
-tests/cases/compiler/duplicateClassElements.ts(6,5): error TS2393: Duplicate function implementation.
+tests/cases/compiler/duplicateClassElements.ts(4,12): error TS2393: Duplicate function implementation.
+tests/cases/compiler/duplicateClassElements.ts(6,12): error TS2393: Duplicate function implementation.
+tests/cases/compiler/duplicateClassElements.ts(8,12): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/duplicateClassElements.ts(9,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/duplicateClassElements.ts(12,9): error TS2300: Duplicate identifier 'x'.
+tests/cases/compiler/duplicateClassElements.ts(21,12): error TS2300: Duplicate identifier 'z'.
 tests/cases/compiler/duplicateClassElements.ts(23,9): error TS2300: Duplicate identifier 'z'.
 tests/cases/compiler/duplicateClassElements.ts(26,9): error TS2300: Duplicate identifier 'z'.
+tests/cases/compiler/duplicateClassElements.ts(29,9): error TS2300: Duplicate identifier 'x2'.
+tests/cases/compiler/duplicateClassElements.ts(32,9): error TS2300: Duplicate identifier 'x2'.
 tests/cases/compiler/duplicateClassElements.ts(34,12): error TS2300: Duplicate identifier 'x2'.
+tests/cases/compiler/duplicateClassElements.ts(36,9): error TS2300: Duplicate identifier 'z2'.
+tests/cases/compiler/duplicateClassElements.ts(39,9): error TS2300: Duplicate identifier 'z2'.
 tests/cases/compiler/duplicateClassElements.ts(41,12): error TS2300: Duplicate identifier 'z2'.
 
 
-==== tests/cases/compiler/duplicateClassElements.ts (18 errors) ====
+==== tests/cases/compiler/duplicateClassElements.ts (26 errors) ====
     class a {
         public a;
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
         public a;
                ~
 !!! error TS2300: Duplicate identifier 'a'.
         public b() {
+               ~
+!!! error TS2393: Duplicate function implementation.
         }
         public b() {
-        ~~~~~~~~~~~~
-        }
-    ~~~~~
+               ~
 !!! error TS2393: Duplicate function implementation.
+        }
         public x;
+               ~
+!!! error TS2300: Duplicate identifier 'x'.
         get x() {
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -57,6 +70,8 @@ tests/cases/compiler/duplicateClassElements.ts(41,12): error TS2300: Duplicate i
         }
     
         public z() {
+               ~
+!!! error TS2300: Duplicate identifier 'z'.
         }
         get z() {
             ~
@@ -75,11 +90,15 @@ tests/cases/compiler/duplicateClassElements.ts(41,12): error TS2300: Duplicate i
         get x2() {
             ~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+            ~~
+!!! error TS2300: Duplicate identifier 'x2'.
             return 10;
         }
         set x2(_x: number) {
             ~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+            ~~
+!!! error TS2300: Duplicate identifier 'x2'.
         }
         public x2;
                ~~
@@ -88,11 +107,15 @@ tests/cases/compiler/duplicateClassElements.ts(41,12): error TS2300: Duplicate i
         get z2() {
             ~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+            ~~
+!!! error TS2300: Duplicate identifier 'z2'.
             return "Hello";
         }
         set z2(_y: string) {
             ~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+            ~~
+!!! error TS2300: Duplicate identifier 'z2'.
         }
         public z2() {
                ~~
diff --git a/tests/baselines/reference/duplicateIdentifierInCatchBlock.errors.txt b/tests/baselines/reference/duplicateIdentifierInCatchBlock.errors.txt
index 08eb464c8ad..d8065df27c8 100644
--- a/tests/baselines/reference/duplicateIdentifierInCatchBlock.errors.txt
+++ b/tests/baselines/reference/duplicateIdentifierInCatchBlock.errors.txt
@@ -1,11 +1,16 @@
+tests/cases/compiler/duplicateIdentifierInCatchBlock.ts(1,5): error TS2300: Duplicate identifier 'v'.
 tests/cases/compiler/duplicateIdentifierInCatchBlock.ts(3,14): error TS2300: Duplicate identifier 'v'.
+tests/cases/compiler/duplicateIdentifierInCatchBlock.ts(6,10): error TS2300: Duplicate identifier 'w'.
 tests/cases/compiler/duplicateIdentifierInCatchBlock.ts(8,9): error TS2300: Duplicate identifier 'w'.
+tests/cases/compiler/duplicateIdentifierInCatchBlock.ts(12,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/duplicateIdentifierInCatchBlock.ts(13,14): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/duplicateIdentifierInCatchBlock.ts(16,9): error TS2403: Subsequent variable declarations must have the same type.  Variable 'p' must be of type 'string', but here has type 'number'.
 
 
-==== tests/cases/compiler/duplicateIdentifierInCatchBlock.ts (4 errors) ====
+==== tests/cases/compiler/duplicateIdentifierInCatchBlock.ts (7 errors) ====
     var v;
+        ~
+!!! error TS2300: Duplicate identifier 'v'.
     try { } catch (e) {
         function v() { }
                  ~
@@ -13,6 +18,8 @@ tests/cases/compiler/duplicateIdentifierInCatchBlock.ts(16,9): error TS2403: Sub
     }
     
     function w() { }
+             ~
+!!! error TS2300: Duplicate identifier 'w'.
     try { } catch (e) {
         var w;
             ~
@@ -21,6 +28,8 @@ tests/cases/compiler/duplicateIdentifierInCatchBlock.ts(16,9): error TS2403: Sub
     
     try { } catch (e) {
         var x;
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
         function x() { } // error
                  ~
 !!! error TS2300: Duplicate identifier 'x'.
diff --git a/tests/baselines/reference/duplicateIdentifiersAcrossContainerBoundaries.errors.txt b/tests/baselines/reference/duplicateIdentifiersAcrossContainerBoundaries.errors.txt
index 783504277e0..6c80d13b2f4 100644
--- a/tests/baselines/reference/duplicateIdentifiersAcrossContainerBoundaries.errors.txt
+++ b/tests/baselines/reference/duplicateIdentifiersAcrossContainerBoundaries.errors.txt
@@ -1,11 +1,16 @@
+tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(2,22): error TS2300: Duplicate identifier 'I'.
 tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(5,18): error TS2300: Duplicate identifier 'I'.
+tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(9,21): error TS2300: Duplicate identifier 'f'.
 tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(12,18): error TS2300: Duplicate identifier 'f'.
+tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(37,12): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(41,16): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts (3 errors) ====
+==== tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts (6 errors) ====
     module M {
         export interface I { }
+                         ~
+!!! error TS2300: Duplicate identifier 'I'.
     }
     module M {
         export class I { } // error
@@ -15,6 +20,8 @@ tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(41,16): er
     
     module M {
         export function f() { }
+                        ~
+!!! error TS2300: Duplicate identifier 'f'.
     }
     module M {
         export class f { } // error
@@ -45,6 +52,8 @@ tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(41,16): er
     
     class Foo {
         static x: number;
+               ~
+!!! error TS2300: Duplicate identifier 'x'.
     }
     
     module Foo {
diff --git a/tests/baselines/reference/duplicateInterfaceMembers1.errors.txt b/tests/baselines/reference/duplicateInterfaceMembers1.errors.txt
index 952b9b3bc42..674d4f601e6 100644
--- a/tests/baselines/reference/duplicateInterfaceMembers1.errors.txt
+++ b/tests/baselines/reference/duplicateInterfaceMembers1.errors.txt
@@ -1,9 +1,12 @@
+tests/cases/compiler/duplicateInterfaceMembers1.ts(2,4): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/duplicateInterfaceMembers1.ts(3,4): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/compiler/duplicateInterfaceMembers1.ts (1 errors) ====
+==== tests/cases/compiler/duplicateInterfaceMembers1.ts (2 errors) ====
     interface Bar {
        x: number;
+       ~
+!!! error TS2300: Duplicate identifier 'x'.
        x: number;
        ~
 !!! error TS2300: Duplicate identifier 'x'.
diff --git a/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt b/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt
index 370a7070505..4c3f6d1eb7e 100644
--- a/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt
+++ b/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt
@@ -2,16 +2,22 @@ tests/cases/compiler/duplicateObjectLiteralProperty.ts(14,9): error TS1056: Acce
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(15,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS1118: An object literal cannot have multiple get/set accessors with the same name.
+tests/cases/compiler/duplicateObjectLiteralProperty.ts(2,5): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(4,5): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(5,5): error TS2300: Duplicate identifier '\u0061'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(6,5): error TS2300: Duplicate identifier 'a'.
+tests/cases/compiler/duplicateObjectLiteralProperty.ts(7,9): error TS2300: Duplicate identifier 'c'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(8,9): error TS2300: Duplicate identifier '"c"'.
+tests/cases/compiler/duplicateObjectLiteralProperty.ts(14,9): error TS2300: Duplicate identifier 'a'.
+tests/cases/compiler/duplicateObjectLiteralProperty.ts(15,9): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS2300: Duplicate identifier 'a'.
 
 
-==== tests/cases/compiler/duplicateObjectLiteralProperty.ts (9 errors) ====
+==== tests/cases/compiler/duplicateObjectLiteralProperty.ts (13 errors) ====
     var x = {
         a: 1,
+        ~
+!!! error TS2300: Duplicate identifier 'a'.
         b: true, // OK
         a: 56,   // Duplicate
         ~
@@ -23,6 +29,8 @@ tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS2300: Dupl
         ~
 !!! error TS2300: Duplicate identifier 'a'.
             c: 1,
+            ~
+!!! error TS2300: Duplicate identifier 'c'.
             "c": 56, // Duplicate
             ~~~
 !!! error TS2300: Duplicate identifier '"c"'.
@@ -34,9 +42,13 @@ tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS2300: Dupl
         get a() { return 0; },
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+            ~
+!!! error TS2300: Duplicate identifier 'a'.
         set a(v: number) { },
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+            ~
+!!! error TS2300: Duplicate identifier 'a'.
         get a() { return 0; }
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
diff --git a/tests/baselines/reference/duplicatePropertiesInStrictMode.errors.txt b/tests/baselines/reference/duplicatePropertiesInStrictMode.errors.txt
index 17a55a7876b..6ae8518677d 100644
--- a/tests/baselines/reference/duplicatePropertiesInStrictMode.errors.txt
+++ b/tests/baselines/reference/duplicatePropertiesInStrictMode.errors.txt
@@ -1,11 +1,14 @@
 tests/cases/compiler/duplicatePropertiesInStrictMode.ts(4,3): error TS1117: An object literal cannot have multiple properties with the same name in strict mode.
+tests/cases/compiler/duplicatePropertiesInStrictMode.ts(3,3): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/duplicatePropertiesInStrictMode.ts(4,3): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/compiler/duplicatePropertiesInStrictMode.ts (2 errors) ====
+==== tests/cases/compiler/duplicatePropertiesInStrictMode.ts (3 errors) ====
     "use strict";
     var x = {
       x: 1,
+      ~
+!!! error TS2300: Duplicate identifier 'x'.
       x: 2
       ~
 !!! error TS1117: An object literal cannot have multiple properties with the same name in strict mode.
diff --git a/tests/baselines/reference/duplicatePropertyNames.errors.txt b/tests/baselines/reference/duplicatePropertyNames.errors.txt
index ac21db7830a..108a88d1451 100644
--- a/tests/baselines/reference/duplicatePropertyNames.errors.txt
+++ b/tests/baselines/reference/duplicatePropertyNames.errors.txt
@@ -1,20 +1,32 @@
+tests/cases/conformance/types/members/duplicatePropertyNames.ts(4,5): error TS2300: Duplicate identifier 'foo'.
 tests/cases/conformance/types/members/duplicatePropertyNames.ts(5,5): error TS2300: Duplicate identifier 'foo'.
+tests/cases/conformance/types/members/duplicatePropertyNames.ts(14,5): error TS2300: Duplicate identifier 'foo'.
 tests/cases/conformance/types/members/duplicatePropertyNames.ts(15,5): error TS2300: Duplicate identifier 'foo'.
+tests/cases/conformance/types/members/duplicatePropertyNames.ts(19,5): error TS2300: Duplicate identifier 'foo'.
 tests/cases/conformance/types/members/duplicatePropertyNames.ts(20,5): error TS2300: Duplicate identifier 'foo'.
+tests/cases/conformance/types/members/duplicatePropertyNames.ts(22,5): error TS2393: Duplicate function implementation.
 tests/cases/conformance/types/members/duplicatePropertyNames.ts(23,5): error TS2393: Duplicate function implementation.
+tests/cases/conformance/types/members/duplicatePropertyNames.ts(25,5): error TS2300: Duplicate identifier 'baz'.
 tests/cases/conformance/types/members/duplicatePropertyNames.ts(26,5): error TS2300: Duplicate identifier 'baz'.
+tests/cases/conformance/types/members/duplicatePropertyNames.ts(30,5): error TS2300: Duplicate identifier 'foo'.
 tests/cases/conformance/types/members/duplicatePropertyNames.ts(31,5): error TS2300: Duplicate identifier 'foo'.
+tests/cases/conformance/types/members/duplicatePropertyNames.ts(35,5): error TS2300: Duplicate identifier 'foo'.
 tests/cases/conformance/types/members/duplicatePropertyNames.ts(36,5): error TS2300: Duplicate identifier 'foo'.
+tests/cases/conformance/types/members/duplicatePropertyNames.ts(38,5): error TS2300: Duplicate identifier 'bar'.
 tests/cases/conformance/types/members/duplicatePropertyNames.ts(39,5): error TS2300: Duplicate identifier 'bar'.
+tests/cases/conformance/types/members/duplicatePropertyNames.ts(43,5): error TS2300: Duplicate identifier 'foo'.
 tests/cases/conformance/types/members/duplicatePropertyNames.ts(44,5): error TS2300: Duplicate identifier 'foo'.
+tests/cases/conformance/types/members/duplicatePropertyNames.ts(45,5): error TS2300: Duplicate identifier 'bar'.
 tests/cases/conformance/types/members/duplicatePropertyNames.ts(46,5): error TS2300: Duplicate identifier 'bar'.
 
 
-==== tests/cases/conformance/types/members/duplicatePropertyNames.ts (10 errors) ====
+==== tests/cases/conformance/types/members/duplicatePropertyNames.ts (20 errors) ====
     // duplicate property names are an error in all types
     
     interface Number {
         foo: string;
+        ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
         foo: string;
         ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
@@ -27,6 +39,8 @@ tests/cases/conformance/types/members/duplicatePropertyNames.ts(46,5): error TS2
     
     interface Array<T> {
         foo: T;
+        ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
         foo: T;
         ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
@@ -34,16 +48,22 @@ tests/cases/conformance/types/members/duplicatePropertyNames.ts(46,5): error TS2
     
     class C {
         foo: string;
+        ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
         foo: string;
         ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
     
         bar(x) { }
+        ~~~
+!!! error TS2393: Duplicate function implementation.
         bar(x) { }
-        ~~~~~~~~~~
+        ~~~
 !!! error TS2393: Duplicate function implementation.
     
         baz = () => { }
+        ~~~
+!!! error TS2300: Duplicate identifier 'baz'.
         baz = () => { }
         ~~~
 !!! error TS2300: Duplicate identifier 'baz'.
@@ -51,6 +71,8 @@ tests/cases/conformance/types/members/duplicatePropertyNames.ts(46,5): error TS2
     
     interface I {
         foo: string;
+        ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
         foo: string;
         ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
@@ -58,11 +80,15 @@ tests/cases/conformance/types/members/duplicatePropertyNames.ts(46,5): error TS2
     
     var a: {
         foo: string;
+        ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
         foo: string;
         ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
     
         bar: () => {};
+        ~~~
+!!! error TS2300: Duplicate identifier 'bar'.
         bar: () => {};
         ~~~
 !!! error TS2300: Duplicate identifier 'bar'.
@@ -70,10 +96,14 @@ tests/cases/conformance/types/members/duplicatePropertyNames.ts(46,5): error TS2
     
     var b = {
         foo: '',
+        ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
         foo: '',
         ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
         bar: () => { },
+        ~~~
+!!! error TS2300: Duplicate identifier 'bar'.
         bar: () => { }
         ~~~
 !!! error TS2300: Duplicate identifier 'bar'.
diff --git a/tests/baselines/reference/duplicateStringNamedProperty1.errors.txt b/tests/baselines/reference/duplicateStringNamedProperty1.errors.txt
index 9353eb34151..7d6c5d6bafc 100644
--- a/tests/baselines/reference/duplicateStringNamedProperty1.errors.txt
+++ b/tests/baselines/reference/duplicateStringNamedProperty1.errors.txt
@@ -1,9 +1,12 @@
+tests/cases/compiler/duplicateStringNamedProperty1.ts(2,5): error TS2300: Duplicate identifier '"artist"'.
 tests/cases/compiler/duplicateStringNamedProperty1.ts(3,5): error TS2300: Duplicate identifier 'artist'.
 
 
-==== tests/cases/compiler/duplicateStringNamedProperty1.ts (1 errors) ====
+==== tests/cases/compiler/duplicateStringNamedProperty1.ts (2 errors) ====
     export interface Album {
         "artist": string;
+        ~~~~~~~~
+!!! error TS2300: Duplicate identifier '"artist"'.
         artist: string;
         ~~~~~~
 !!! error TS2300: Duplicate identifier 'artist'.
diff --git a/tests/baselines/reference/enumGenericTypeClash.errors.txt b/tests/baselines/reference/enumGenericTypeClash.errors.txt
index adf345870de..23007175e4c 100644
--- a/tests/baselines/reference/enumGenericTypeClash.errors.txt
+++ b/tests/baselines/reference/enumGenericTypeClash.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/enumGenericTypeClash.ts(1,7): error TS2300: Duplicate identifier 'X'.
 tests/cases/compiler/enumGenericTypeClash.ts(2,6): error TS2300: Duplicate identifier 'X'.
 
 
-==== tests/cases/compiler/enumGenericTypeClash.ts (1 errors) ====
+==== tests/cases/compiler/enumGenericTypeClash.ts (2 errors) ====
     class X<A,B,C> { }
+          ~
+!!! error TS2300: Duplicate identifier 'X'.
     enum X { MyVal }
          ~
 !!! error TS2300: Duplicate identifier 'X'.
diff --git a/tests/baselines/reference/enumIdenticalIdentifierValues.errors.txt b/tests/baselines/reference/enumIdenticalIdentifierValues.errors.txt
index 26b5da7d0cf..551b5d9d929 100644
--- a/tests/baselines/reference/enumIdenticalIdentifierValues.errors.txt
+++ b/tests/baselines/reference/enumIdenticalIdentifierValues.errors.txt
@@ -1,9 +1,12 @@
+tests/cases/compiler/enumIdenticalIdentifierValues.ts(2,5): error TS2300: Duplicate identifier '1'.
 tests/cases/compiler/enumIdenticalIdentifierValues.ts(3,5): error TS2300: Duplicate identifier '1.0'.
 
 
-==== tests/cases/compiler/enumIdenticalIdentifierValues.ts (1 errors) ====
+==== tests/cases/compiler/enumIdenticalIdentifierValues.ts (2 errors) ====
     enum Enum {
         1,
+        ~
+!!! error TS2300: Duplicate identifier '1'.
         1.0
         ~~~
 !!! error TS2300: Duplicate identifier '1.0'.
diff --git a/tests/baselines/reference/es6ClassTest9.errors.txt b/tests/baselines/reference/es6ClassTest9.errors.txt
index 3cd59059f89..ae7d1ba92d5 100644
--- a/tests/baselines/reference/es6ClassTest9.errors.txt
+++ b/tests/baselines/reference/es6ClassTest9.errors.txt
@@ -1,14 +1,17 @@
 tests/cases/compiler/es6ClassTest9.ts(1,18): error TS1005: '{' expected.
 tests/cases/compiler/es6ClassTest9.ts(1,19): error TS1109: Expression expected.
+tests/cases/compiler/es6ClassTest9.ts(1,15): error TS2300: Duplicate identifier 'foo'.
 tests/cases/compiler/es6ClassTest9.ts(2,10): error TS2300: Duplicate identifier 'foo'.
 
 
-==== tests/cases/compiler/es6ClassTest9.ts (3 errors) ====
+==== tests/cases/compiler/es6ClassTest9.ts (4 errors) ====
     declare class foo();
                      ~
 !!! error TS1005: '{' expected.
                       ~
 !!! error TS1109: Expression expected.
+                  ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
     function foo() {}
              ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
diff --git a/tests/baselines/reference/exportSameNameFuncVar.errors.txt b/tests/baselines/reference/exportSameNameFuncVar.errors.txt
index 0103d0e8968..a06457e88ae 100644
--- a/tests/baselines/reference/exportSameNameFuncVar.errors.txt
+++ b/tests/baselines/reference/exportSameNameFuncVar.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/exportSameNameFuncVar.ts(1,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/exportSameNameFuncVar.ts(2,17): error TS2300: Duplicate identifier 'a'.
 
 
-==== tests/cases/compiler/exportSameNameFuncVar.ts (1 errors) ====
+==== tests/cases/compiler/exportSameNameFuncVar.ts (2 errors) ====
     export var a = 10;
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
     export function a() {
                     ~
 !!! error TS2300: Duplicate identifier 'a'.
diff --git a/tests/baselines/reference/extension.errors.txt b/tests/baselines/reference/extension.errors.txt
index 9756d2920d1..e55f15f4381 100644
--- a/tests/baselines/reference/extension.errors.txt
+++ b/tests/baselines/reference/extension.errors.txt
@@ -1,11 +1,12 @@
 tests/cases/compiler/extension.ts(16,5): error TS1128: Declaration or statement expected.
 tests/cases/compiler/extension.ts(16,22): error TS1005: ';' expected.
+tests/cases/compiler/extension.ts(10,18): error TS2300: Duplicate identifier 'C'.
 tests/cases/compiler/extension.ts(16,12): error TS2304: Cannot find name 'extension'.
 tests/cases/compiler/extension.ts(16,28): error TS2300: Duplicate identifier 'C'.
 tests/cases/compiler/extension.ts(22,3): error TS2339: Property 'pe' does not exist on type 'C'.
 
 
-==== tests/cases/compiler/extension.ts (5 errors) ====
+==== tests/cases/compiler/extension.ts (6 errors) ====
     interface I {
         x;
     }
@@ -16,6 +17,8 @@ tests/cases/compiler/extension.ts(22,3): error TS2339: Property 'pe' does not ex
     
     declare module M {
         export class C {
+                     ~
+!!! error TS2300: Duplicate identifier 'C'.
             public p:number;
         }
     }
diff --git a/tests/baselines/reference/fieldAndGetterWithSameName.errors.txt b/tests/baselines/reference/fieldAndGetterWithSameName.errors.txt
index ef205adfd42..dd2374f2447 100644
--- a/tests/baselines/reference/fieldAndGetterWithSameName.errors.txt
+++ b/tests/baselines/reference/fieldAndGetterWithSameName.errors.txt
@@ -1,10 +1,13 @@
 tests/cases/compiler/fieldAndGetterWithSameName.ts(3,7): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/compiler/fieldAndGetterWithSameName.ts(2,5): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/fieldAndGetterWithSameName.ts(3,7): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/compiler/fieldAndGetterWithSameName.ts (2 errors) ====
+==== tests/cases/compiler/fieldAndGetterWithSameName.ts (3 errors) ====
     export class C {
         x: number;
+        ~
+!!! error TS2300: Duplicate identifier 'x'.
       get x(): number { return 1; }
           ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
diff --git a/tests/baselines/reference/funClodule.errors.txt b/tests/baselines/reference/funClodule.errors.txt
index 20598f276f3..72a9ed0db51 100644
--- a/tests/baselines/reference/funClodule.errors.txt
+++ b/tests/baselines/reference/funClodule.errors.txt
@@ -1,11 +1,21 @@
+tests/cases/compiler/funClodule.ts(1,18): error TS2300: Duplicate identifier 'foo'.
+tests/cases/compiler/funClodule.ts(2,16): error TS2300: Duplicate identifier 'foo'.
 tests/cases/compiler/funClodule.ts(5,15): error TS2300: Duplicate identifier 'foo'.
+tests/cases/compiler/funClodule.ts(8,15): error TS2300: Duplicate identifier 'foo2'.
+tests/cases/compiler/funClodule.ts(9,16): error TS2300: Duplicate identifier 'foo2'.
 tests/cases/compiler/funClodule.ts(12,18): error TS2300: Duplicate identifier 'foo2'.
+tests/cases/compiler/funClodule.ts(15,10): error TS2300: Duplicate identifier 'foo3'.
+tests/cases/compiler/funClodule.ts(16,8): error TS2300: Duplicate identifier 'foo3'.
 tests/cases/compiler/funClodule.ts(19,7): error TS2300: Duplicate identifier 'foo3'.
 
 
-==== tests/cases/compiler/funClodule.ts (3 errors) ====
+==== tests/cases/compiler/funClodule.ts (9 errors) ====
     declare function foo();
+                     ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
     declare module foo {
+                   ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
         export function x(): any;
     }
     declare class foo { } // Should error
@@ -14,7 +24,11 @@ tests/cases/compiler/funClodule.ts(19,7): error TS2300: Duplicate identifier 'fo
     
     
     declare class foo2 { }
+                  ~~~~
+!!! error TS2300: Duplicate identifier 'foo2'.
     declare module foo2 {
+                   ~~~~
+!!! error TS2300: Duplicate identifier 'foo2'.
         export function x(): any;
     }
     declare function foo2(); // Should error
@@ -23,7 +37,11 @@ tests/cases/compiler/funClodule.ts(19,7): error TS2300: Duplicate identifier 'fo
     
     
     function foo3() { }
+             ~~~~
+!!! error TS2300: Duplicate identifier 'foo3'.
     module foo3 {
+           ~~~~
+!!! error TS2300: Duplicate identifier 'foo3'.
          export function x(): any { }
     }
     class foo3 { } // Should error
diff --git a/tests/baselines/reference/functionAndPropertyNameConflict.errors.txt b/tests/baselines/reference/functionAndPropertyNameConflict.errors.txt
index 8b1efe089c1..640844064c4 100644
--- a/tests/baselines/reference/functionAndPropertyNameConflict.errors.txt
+++ b/tests/baselines/reference/functionAndPropertyNameConflict.errors.txt
@@ -1,10 +1,13 @@
 tests/cases/compiler/functionAndPropertyNameConflict.ts(3,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/compiler/functionAndPropertyNameConflict.ts(2,12): error TS2300: Duplicate identifier 'aaaaa'.
 tests/cases/compiler/functionAndPropertyNameConflict.ts(3,16): error TS2300: Duplicate identifier 'aaaaa'.
 
 
-==== tests/cases/compiler/functionAndPropertyNameConflict.ts (2 errors) ====
+==== tests/cases/compiler/functionAndPropertyNameConflict.ts (3 errors) ====
     class C65 {
         public aaaaa() { }
+               ~~~~~
+!!! error TS2300: Duplicate identifier 'aaaaa'.
         public get aaaaa() {
                    ~~~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
diff --git a/tests/baselines/reference/functionCall15.errors.txt b/tests/baselines/reference/functionCall15.errors.txt
index 09c246d34dc..4b6acf34e14 100644
--- a/tests/baselines/reference/functionCall15.errors.txt
+++ b/tests/baselines/reference/functionCall15.errors.txt
@@ -1,7 +1,10 @@
+tests/cases/compiler/functionCall15.ts(1,25): error TS2300: Duplicate identifier 'b'.
 tests/cases/compiler/functionCall15.ts(1,39): error TS2300: Duplicate identifier 'b'.
 
 
-==== tests/cases/compiler/functionCall15.ts (1 errors) ====
+==== tests/cases/compiler/functionCall15.ts (2 errors) ====
     function foo(a?:string, b?:number, ...b:number[]){}
+                            ~
+!!! error TS2300: Duplicate identifier 'b'.
                                           ~
 !!! error TS2300: Duplicate identifier 'b'.
\ No newline at end of file
diff --git a/tests/baselines/reference/functionNameConflicts.errors.txt b/tests/baselines/reference/functionNameConflicts.errors.txt
index 08a2c5c462d..86fa348d817 100644
--- a/tests/baselines/reference/functionNameConflicts.errors.txt
+++ b/tests/baselines/reference/functionNameConflicts.errors.txt
@@ -1,39 +1,54 @@
+tests/cases/conformance/functions/functionNameConflicts.ts(5,14): error TS2300: Duplicate identifier 'fn1'.
 tests/cases/conformance/functions/functionNameConflicts.ts(6,9): error TS2300: Duplicate identifier 'fn1'.
+tests/cases/conformance/functions/functionNameConflicts.ts(8,9): error TS2300: Duplicate identifier 'fn2'.
 tests/cases/conformance/functions/functionNameConflicts.ts(9,14): error TS2300: Duplicate identifier 'fn2'.
+tests/cases/conformance/functions/functionNameConflicts.ts(12,10): error TS2300: Duplicate identifier 'fn3'.
 tests/cases/conformance/functions/functionNameConflicts.ts(13,5): error TS2300: Duplicate identifier 'fn3'.
+tests/cases/conformance/functions/functionNameConflicts.ts(16,9): error TS2300: Duplicate identifier 'fn4'.
 tests/cases/conformance/functions/functionNameConflicts.ts(17,14): error TS2300: Duplicate identifier 'fn4'.
+tests/cases/conformance/functions/functionNameConflicts.ts(19,14): error TS2300: Duplicate identifier 'fn5'.
 tests/cases/conformance/functions/functionNameConflicts.ts(20,9): error TS2300: Duplicate identifier 'fn5'.
 tests/cases/conformance/functions/functionNameConflicts.ts(24,10): error TS2389: Function implementation name must be 'over'.
 
 
-==== tests/cases/conformance/functions/functionNameConflicts.ts (6 errors) ====
+==== tests/cases/conformance/functions/functionNameConflicts.ts (11 errors) ====
     //Function and variable of the same name in same declaration space
     //Function overload with different name from implementation signature 
     
     module M {
         function fn1() { }
+                 ~~~
+!!! error TS2300: Duplicate identifier 'fn1'.
         var fn1;
             ~~~
 !!! error TS2300: Duplicate identifier 'fn1'.
     
         var fn2;
+            ~~~
+!!! error TS2300: Duplicate identifier 'fn2'.
         function fn2() { }
                  ~~~
 !!! error TS2300: Duplicate identifier 'fn2'.
     }
     
     function fn3() { }
+             ~~~
+!!! error TS2300: Duplicate identifier 'fn3'.
     var fn3;
         ~~~
 !!! error TS2300: Duplicate identifier 'fn3'.
     
     function func() {
         var fn4;
+            ~~~
+!!! error TS2300: Duplicate identifier 'fn4'.
         function fn4() { }
                  ~~~
 !!! error TS2300: Duplicate identifier 'fn4'.
     
         function fn5() { }
+                 ~~~
+!!! error TS2300: Duplicate identifier 'fn5'.
         var fn5;
             ~~~
 !!! error TS2300: Duplicate identifier 'fn5'.
diff --git a/tests/baselines/reference/functionWithSameNameAsField.errors.txt b/tests/baselines/reference/functionWithSameNameAsField.errors.txt
index e1ba390cf94..168b9191df4 100644
--- a/tests/baselines/reference/functionWithSameNameAsField.errors.txt
+++ b/tests/baselines/reference/functionWithSameNameAsField.errors.txt
@@ -1,9 +1,12 @@
+tests/cases/compiler/functionWithSameNameAsField.ts(2,12): error TS2300: Duplicate identifier 'total'.
 tests/cases/compiler/functionWithSameNameAsField.ts(3,12): error TS2300: Duplicate identifier 'total'.
 
 
-==== tests/cases/compiler/functionWithSameNameAsField.ts (1 errors) ====
+==== tests/cases/compiler/functionWithSameNameAsField.ts (2 errors) ====
     class TestProgressBar {
         public total: number;
+               ~~~~~
+!!! error TS2300: Duplicate identifier 'total'.
         public total(total: number) {
                ~~~~~
 !!! error TS2300: Duplicate identifier 'total'.
diff --git a/tests/baselines/reference/genericClassesRedeclaration.errors.txt b/tests/baselines/reference/genericClassesRedeclaration.errors.txt
index 8cf048c3061..abdea2b052b 100644
--- a/tests/baselines/reference/genericClassesRedeclaration.errors.txt
+++ b/tests/baselines/reference/genericClassesRedeclaration.errors.txt
@@ -1,9 +1,11 @@
+tests/cases/compiler/genericClassesRedeclaration.ts(16,11): error TS2300: Duplicate identifier 'StringHashTable'.
+tests/cases/compiler/genericClassesRedeclaration.ts(29,11): error TS2300: Duplicate identifier 'IdentiferNameHashTable'.
 tests/cases/compiler/genericClassesRedeclaration.ts(42,9): error TS2374: Duplicate string index signature.
 tests/cases/compiler/genericClassesRedeclaration.ts(55,11): error TS2300: Duplicate identifier 'StringHashTable'.
 tests/cases/compiler/genericClassesRedeclaration.ts(68,11): error TS2300: Duplicate identifier 'IdentiferNameHashTable'.
 
 
-==== tests/cases/compiler/genericClassesRedeclaration.ts (3 errors) ====
+==== tests/cases/compiler/genericClassesRedeclaration.ts (5 errors) ====
     declare module TypeScript {
         interface IIndexable<T> {
             [s: string]: T;
@@ -20,6 +22,8 @@ tests/cases/compiler/genericClassesRedeclaration.ts(68,11): error TS2300: Duplic
             lookup(key: string): T;
         }
         class StringHashTable<T> implements IHashTable<T> {
+              ~~~~~~~~~~~~~~~
+!!! error TS2300: Duplicate identifier 'StringHashTable'.
             private itemCount;
             private table;
             public getAllKeys(): string[];
@@ -33,6 +37,8 @@ tests/cases/compiler/genericClassesRedeclaration.ts(68,11): error TS2300: Duplic
             public remove(key: string): void;
         }
         class IdentiferNameHashTable<T> extends StringHashTable<T> {
+              ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2300: Duplicate identifier 'IdentiferNameHashTable'.
             public getAllKeys(): string[];
             public add(key: string, data: T): boolean;
             public addOrUpdate(key: string, data: T): boolean;
diff --git a/tests/baselines/reference/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.errors.txt b/tests/baselines/reference/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.errors.txt
index ea6068225d9..a7e8155c220 100644
--- a/tests/baselines/reference/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.errors.txt
+++ b/tests/baselines/reference/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.errors.txt
@@ -1,18 +1,27 @@
 tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(21,20): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(1,18): error TS2300: Duplicate identifier '_'.
 tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(1,41): error TS2304: Cannot find name '_'.
+tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(2,18): error TS2300: Duplicate identifier '_'.
 tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(2,34): error TS2304: Cannot find name '_'.
+tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(4,16): error TS2300: Duplicate identifier '_'.
 tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(15,15): error TS2300: Duplicate identifier '_'.
 
 
-==== tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts (4 errors) ====
+==== tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts (7 errors) ====
     declare function _<T>(value: Array<T>): _<T>;
+                     ~
+!!! error TS2300: Duplicate identifier '_'.
                                             ~~~~
 !!! error TS2304: Cannot find name '_'.
     declare function _<T>(value: T): _<T>;
+                     ~
+!!! error TS2300: Duplicate identifier '_'.
                                      ~~~~
 !!! error TS2304: Cannot find name '_'.
     
     declare module _ {
+                   ~
+!!! error TS2300: Duplicate identifier '_'.
         export function each<T>(
             //list: List<T>,
             //iterator: ListIterator<T, void>,
diff --git a/tests/baselines/reference/gettersAndSettersErrors.errors.txt b/tests/baselines/reference/gettersAndSettersErrors.errors.txt
index b87dba8809c..95fb571d9b8 100644
--- a/tests/baselines/reference/gettersAndSettersErrors.errors.txt
+++ b/tests/baselines/reference/gettersAndSettersErrors.errors.txt
@@ -4,19 +4,25 @@ tests/cases/compiler/gettersAndSettersErrors.ts(6,16): error TS1056: Accessors a
 tests/cases/compiler/gettersAndSettersErrors.ts(7,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/gettersAndSettersErrors.ts(11,17): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/gettersAndSettersErrors.ts(12,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/compiler/gettersAndSettersErrors.ts(2,16): error TS2300: Duplicate identifier 'Foo'.
+tests/cases/compiler/gettersAndSettersErrors.ts(3,16): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/gettersAndSettersErrors.ts(5,12): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/gettersAndSettersErrors.ts(11,17): error TS2379: Getter and setter accessors do not agree in visibility.
 tests/cases/compiler/gettersAndSettersErrors.ts(12,16): error TS2379: Getter and setter accessors do not agree in visibility.
 
 
-==== tests/cases/compiler/gettersAndSettersErrors.ts (9 errors) ====
+==== tests/cases/compiler/gettersAndSettersErrors.ts (11 errors) ====
     class C {
         public get Foo() { return "foo";} // ok
                    ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
         public set Foo(foo:string) {} // ok
                    ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
     
         public Foo = 0; // error - duplicate identifier Foo - confirmed
                ~~~
diff --git a/tests/baselines/reference/giant.errors.txt b/tests/baselines/reference/giant.errors.txt
index 01ddc29ea05..5ef1393915d 100644
--- a/tests/baselines/reference/giant.errors.txt
+++ b/tests/baselines/reference/giant.errors.txt
@@ -145,89 +145,143 @@ tests/cases/compiler/giant.ts(672,22): error TS1037: A function implementation c
 tests/cases/compiler/giant.ts(672,25): error TS1036: Statements are not allowed in ambient contexts.
 tests/cases/compiler/giant.ts(676,30): error TS1037: A function implementation cannot be declared in an ambient context.
 tests/cases/compiler/giant.ts(676,33): error TS1036: Statements are not allowed in ambient contexts.
+tests/cases/compiler/giant.ts(23,12): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(24,16): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(24,16): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(25,12): error TS2300: Duplicate identifier 'psF'.
 tests/cases/compiler/giant.ts(26,16): error TS2300: Duplicate identifier 'psF'.
+tests/cases/compiler/giant.ts(27,13): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(28,17): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(28,17): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(29,13): error TS2300: Duplicate identifier 'rsF'.
 tests/cases/compiler/giant.ts(30,17): error TS2300: Duplicate identifier 'rsF'.
+tests/cases/compiler/giant.ts(33,12): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(34,16): error TS2300: Duplicate identifier 'tsF'.
+tests/cases/compiler/giant.ts(35,12): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(36,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(36,16): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
 tests/cases/compiler/giant.ts(76,5): error TS2386: Overload signatures must all be optional or required.
+tests/cases/compiler/giant.ts(87,16): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(88,20): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(88,20): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(89,16): error TS2300: Duplicate identifier 'psF'.
 tests/cases/compiler/giant.ts(90,20): error TS2300: Duplicate identifier 'psF'.
+tests/cases/compiler/giant.ts(91,17): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(92,21): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(92,21): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(93,17): error TS2300: Duplicate identifier 'rsF'.
 tests/cases/compiler/giant.ts(94,21): error TS2300: Duplicate identifier 'rsF'.
+tests/cases/compiler/giant.ts(97,16): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(98,20): error TS2300: Duplicate identifier 'tsF'.
+tests/cases/compiler/giant.ts(99,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(100,20): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(100,20): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
 tests/cases/compiler/giant.ts(140,9): error TS2386: Overload signatures must all be optional or required.
+tests/cases/compiler/giant.ts(166,16): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(167,20): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(167,20): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(168,16): error TS2300: Duplicate identifier 'psF'.
 tests/cases/compiler/giant.ts(169,20): error TS2300: Duplicate identifier 'psF'.
+tests/cases/compiler/giant.ts(170,17): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(171,21): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(171,21): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(172,17): error TS2300: Duplicate identifier 'rsF'.
 tests/cases/compiler/giant.ts(173,21): error TS2300: Duplicate identifier 'rsF'.
+tests/cases/compiler/giant.ts(176,16): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(177,20): error TS2300: Duplicate identifier 'tsF'.
+tests/cases/compiler/giant.ts(178,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(179,20): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(179,20): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
 tests/cases/compiler/giant.ts(219,9): error TS2386: Overload signatures must all be optional or required.
+tests/cases/compiler/giant.ts(245,16): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(246,20): error TS2300: Duplicate identifier 'pgF'.
+tests/cases/compiler/giant.ts(247,16): error TS2300: Duplicate identifier 'psF'.
 tests/cases/compiler/giant.ts(248,20): error TS2300: Duplicate identifier 'psF'.
+tests/cases/compiler/giant.ts(249,17): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(250,21): error TS2300: Duplicate identifier 'rgF'.
+tests/cases/compiler/giant.ts(251,17): error TS2300: Duplicate identifier 'rsF'.
 tests/cases/compiler/giant.ts(252,21): error TS2300: Duplicate identifier 'rsF'.
+tests/cases/compiler/giant.ts(255,16): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(256,20): error TS2300: Duplicate identifier 'tsF'.
+tests/cases/compiler/giant.ts(257,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(258,20): error TS2300: Duplicate identifier 'tgF'.
+tests/cases/compiler/giant.ts(281,12): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(282,16): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(282,16): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(283,12): error TS2300: Duplicate identifier 'psF'.
 tests/cases/compiler/giant.ts(284,16): error TS2300: Duplicate identifier 'psF'.
+tests/cases/compiler/giant.ts(285,13): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(286,17): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(286,17): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(287,13): error TS2300: Duplicate identifier 'rsF'.
 tests/cases/compiler/giant.ts(288,17): error TS2300: Duplicate identifier 'rsF'.
+tests/cases/compiler/giant.ts(291,12): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(292,16): error TS2300: Duplicate identifier 'tsF'.
+tests/cases/compiler/giant.ts(293,12): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(294,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(294,16): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
 tests/cases/compiler/giant.ts(334,5): error TS2386: Overload signatures must all be optional or required.
+tests/cases/compiler/giant.ts(345,16): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(346,20): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(346,20): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(347,16): error TS2300: Duplicate identifier 'psF'.
 tests/cases/compiler/giant.ts(348,20): error TS2300: Duplicate identifier 'psF'.
+tests/cases/compiler/giant.ts(349,17): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(350,21): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(350,21): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(351,17): error TS2300: Duplicate identifier 'rsF'.
 tests/cases/compiler/giant.ts(352,21): error TS2300: Duplicate identifier 'rsF'.
+tests/cases/compiler/giant.ts(355,16): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(356,20): error TS2300: Duplicate identifier 'tsF'.
+tests/cases/compiler/giant.ts(357,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(358,20): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(358,20): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
 tests/cases/compiler/giant.ts(398,9): error TS2386: Overload signatures must all be optional or required.
+tests/cases/compiler/giant.ts(424,16): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(425,20): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(425,20): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(426,16): error TS2300: Duplicate identifier 'psF'.
 tests/cases/compiler/giant.ts(427,20): error TS2300: Duplicate identifier 'psF'.
+tests/cases/compiler/giant.ts(428,17): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(429,21): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(429,21): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
+tests/cases/compiler/giant.ts(430,17): error TS2300: Duplicate identifier 'rsF'.
 tests/cases/compiler/giant.ts(431,21): error TS2300: Duplicate identifier 'rsF'.
+tests/cases/compiler/giant.ts(434,16): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(435,20): error TS2300: Duplicate identifier 'tsF'.
+tests/cases/compiler/giant.ts(436,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(437,20): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(437,20): error TS2378: A 'get' accessor must return a value or consist of a single 'throw' statement.
 tests/cases/compiler/giant.ts(477,9): error TS2386: Overload signatures must all be optional or required.
+tests/cases/compiler/giant.ts(503,16): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(504,20): error TS2300: Duplicate identifier 'pgF'.
+tests/cases/compiler/giant.ts(505,16): error TS2300: Duplicate identifier 'psF'.
 tests/cases/compiler/giant.ts(506,20): error TS2300: Duplicate identifier 'psF'.
+tests/cases/compiler/giant.ts(507,17): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(508,21): error TS2300: Duplicate identifier 'rgF'.
+tests/cases/compiler/giant.ts(509,17): error TS2300: Duplicate identifier 'rsF'.
 tests/cases/compiler/giant.ts(510,21): error TS2300: Duplicate identifier 'rsF'.
+tests/cases/compiler/giant.ts(513,16): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(514,20): error TS2300: Duplicate identifier 'tsF'.
+tests/cases/compiler/giant.ts(515,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(516,20): error TS2300: Duplicate identifier 'tgF'.
+tests/cases/compiler/giant.ts(539,12): error TS2300: Duplicate identifier 'pgF'.
 tests/cases/compiler/giant.ts(540,16): error TS2300: Duplicate identifier 'pgF'.
+tests/cases/compiler/giant.ts(541,12): error TS2300: Duplicate identifier 'psF'.
 tests/cases/compiler/giant.ts(542,16): error TS2300: Duplicate identifier 'psF'.
+tests/cases/compiler/giant.ts(543,13): error TS2300: Duplicate identifier 'rgF'.
 tests/cases/compiler/giant.ts(544,17): error TS2300: Duplicate identifier 'rgF'.
+tests/cases/compiler/giant.ts(545,13): error TS2300: Duplicate identifier 'rsF'.
 tests/cases/compiler/giant.ts(546,17): error TS2300: Duplicate identifier 'rsF'.
+tests/cases/compiler/giant.ts(549,12): error TS2300: Duplicate identifier 'tsF'.
 tests/cases/compiler/giant.ts(550,16): error TS2300: Duplicate identifier 'tsF'.
+tests/cases/compiler/giant.ts(551,12): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(552,16): error TS2300: Duplicate identifier 'tgF'.
 tests/cases/compiler/giant.ts(602,9): error TS2386: Overload signatures must all be optional or required.
 tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all be optional or required.
 
 
-==== tests/cases/compiler/giant.ts (227 errors) ====
+==== tests/cases/compiler/giant.ts (281 errors) ====
     
     /*
         Prefixes
@@ -251,6 +305,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         public pF() { }
         private rF() { }
         public pgF() { }
+               ~~~
+!!! error TS2300: Duplicate identifier 'pgF'.
         public get pgF()
                    ~~~
 !!! error TS2300: Duplicate identifier 'pgF'.
@@ -259,12 +315,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         public psF(param:any) { }
         ~~~~~~
 !!! error TS1005: '{' expected.
+               ~~~
+!!! error TS2300: Duplicate identifier 'psF'.
         public set psF(param:any)
                    ~~~
 !!! error TS2300: Duplicate identifier 'psF'.
         private rgF() { }
         ~~~~~~~
 !!! error TS1005: '{' expected.
+                ~~~
+!!! error TS2300: Duplicate identifier 'rgF'.
         private get rgF()
                     ~~~
 !!! error TS2300: Duplicate identifier 'rgF'.
@@ -273,6 +333,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         private rsF(param:any) { }
         ~~~~~~~
 !!! error TS1005: '{' expected.
+                ~~~
+!!! error TS2300: Duplicate identifier 'rsF'.
         private set rsF(param:any)
                     ~~~
 !!! error TS2300: Duplicate identifier 'rsF'.
@@ -281,12 +343,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
 !!! error TS1005: '{' expected.
         static tF() { }
         static tsF(param:any) { }
+               ~~~
+!!! error TS2300: Duplicate identifier 'tsF'.
         static set tsF(param:any)
                    ~~~
 !!! error TS2300: Duplicate identifier 'tsF'.
         static tgF() { }
         ~~~~~~
 !!! error TS1005: '{' expected.
+               ~~~
+!!! error TS2300: Duplicate identifier 'tgF'.
         static get tgF()
                    ~~~
 !!! error TS2300: Duplicate identifier 'tgF'.
@@ -353,6 +419,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public pF() { }
             private rF() { }
             public pgF() { }
+                   ~~~
+!!! error TS2300: Duplicate identifier 'pgF'.
             public get pgF()
                        ~~~
 !!! error TS2300: Duplicate identifier 'pgF'.
@@ -361,12 +429,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public psF(param:any) { }
             ~~~~~~
 !!! error TS1005: '{' expected.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'psF'.
             public set psF(param:any)
                        ~~~
 !!! error TS2300: Duplicate identifier 'psF'.
             private rgF() { }
             ~~~~~~~
 !!! error TS1005: '{' expected.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rgF'.
             private get rgF()
                         ~~~
 !!! error TS2300: Duplicate identifier 'rgF'.
@@ -375,6 +447,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             private rsF(param:any) { }
             ~~~~~~~
 !!! error TS1005: '{' expected.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rsF'.
             private set rsF(param:any)
                         ~~~
 !!! error TS2300: Duplicate identifier 'rsF'.
@@ -383,12 +457,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
 !!! error TS1005: '{' expected.
             static tF() { }
             static tsF(param:any) { }
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tsF'.
             static set tsF(param:any)
                        ~~~
 !!! error TS2300: Duplicate identifier 'tsF'.
             static tgF() { }
             ~~~~~~
 !!! error TS1005: '{' expected.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tgF'.
             static get tgF()
                        ~~~
 !!! error TS2300: Duplicate identifier 'tgF'.
@@ -472,6 +550,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public pF() { }
             private rF() { }
             public pgF() { }
+                   ~~~
+!!! error TS2300: Duplicate identifier 'pgF'.
             public get pgF()
                        ~~~
 !!! error TS2300: Duplicate identifier 'pgF'.
@@ -480,12 +560,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public psF(param:any) { }
             ~~~~~~
 !!! error TS1005: '{' expected.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'psF'.
             public set psF(param:any)
                        ~~~
 !!! error TS2300: Duplicate identifier 'psF'.
             private rgF() { }
             ~~~~~~~
 !!! error TS1005: '{' expected.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rgF'.
             private get rgF()
                         ~~~
 !!! error TS2300: Duplicate identifier 'rgF'.
@@ -494,6 +578,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             private rsF(param:any) { }
             ~~~~~~~
 !!! error TS1005: '{' expected.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rsF'.
             private set rsF(param:any)
                         ~~~
 !!! error TS2300: Duplicate identifier 'rsF'.
@@ -502,12 +588,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
 !!! error TS1005: '{' expected.
             static tF() { }
             static tsF(param:any) { }
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tsF'.
             static set tsF(param:any)
                        ~~~
 !!! error TS2300: Duplicate identifier 'tsF'.
             static tgF() { }
             ~~~~~~
 !!! error TS1005: '{' expected.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tgF'.
             static get tgF()
                        ~~~
 !!! error TS2300: Duplicate identifier 'tgF'.
@@ -601,6 +691,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public pgF() { }
                          ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'pgF'.
             public get pgF()
                        ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -609,6 +701,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public psF(param:any) { }
                                   ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'psF'.
             public set psF(param:any)
                        ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -617,6 +711,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             private rgF() { }
                           ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rgF'.
             private get rgF()
                         ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -625,6 +721,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             private rsF(param:any) { }
                                    ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rsF'.
             private set rsF(param:any)
                         ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -637,6 +735,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             static tsF(param:any) { }
                                   ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tsF'.
             static set tsF(param:any)
                        ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -645,6 +745,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             static tgF() { }
                          ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tgF'.
             static get tgF()
                        ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -681,6 +783,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         public pF() { }
         private rF() { }
         public pgF() { }
+               ~~~
+!!! error TS2300: Duplicate identifier 'pgF'.
         public get pgF()
                    ~~~
 !!! error TS2300: Duplicate identifier 'pgF'.
@@ -689,12 +793,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         public psF(param:any) { }
         ~~~~~~
 !!! error TS1005: '{' expected.
+               ~~~
+!!! error TS2300: Duplicate identifier 'psF'.
         public set psF(param:any)
                    ~~~
 !!! error TS2300: Duplicate identifier 'psF'.
         private rgF() { }
         ~~~~~~~
 !!! error TS1005: '{' expected.
+                ~~~
+!!! error TS2300: Duplicate identifier 'rgF'.
         private get rgF()
                     ~~~
 !!! error TS2300: Duplicate identifier 'rgF'.
@@ -703,6 +811,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         private rsF(param:any) { }
         ~~~~~~~
 !!! error TS1005: '{' expected.
+                ~~~
+!!! error TS2300: Duplicate identifier 'rsF'.
         private set rsF(param:any)
                     ~~~
 !!! error TS2300: Duplicate identifier 'rsF'.
@@ -711,12 +821,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
 !!! error TS1005: '{' expected.
         static tF() { }
         static tsF(param:any) { }
+               ~~~
+!!! error TS2300: Duplicate identifier 'tsF'.
         static set tsF(param:any)
                    ~~~
 !!! error TS2300: Duplicate identifier 'tsF'.
         static tgF() { }
         ~~~~~~
 !!! error TS1005: '{' expected.
+               ~~~
+!!! error TS2300: Duplicate identifier 'tgF'.
         static get tgF()
                    ~~~
 !!! error TS2300: Duplicate identifier 'tgF'.
@@ -783,6 +897,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public pF() { }
             private rF() { }
             public pgF() { }
+                   ~~~
+!!! error TS2300: Duplicate identifier 'pgF'.
             public get pgF()
                        ~~~
 !!! error TS2300: Duplicate identifier 'pgF'.
@@ -791,12 +907,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public psF(param:any) { }
             ~~~~~~
 !!! error TS1005: '{' expected.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'psF'.
             public set psF(param:any)
                        ~~~
 !!! error TS2300: Duplicate identifier 'psF'.
             private rgF() { }
             ~~~~~~~
 !!! error TS1005: '{' expected.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rgF'.
             private get rgF()
                         ~~~
 !!! error TS2300: Duplicate identifier 'rgF'.
@@ -805,6 +925,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             private rsF(param:any) { }
             ~~~~~~~
 !!! error TS1005: '{' expected.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rsF'.
             private set rsF(param:any)
                         ~~~
 !!! error TS2300: Duplicate identifier 'rsF'.
@@ -813,12 +935,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
 !!! error TS1005: '{' expected.
             static tF() { }
             static tsF(param:any) { }
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tsF'.
             static set tsF(param:any)
                        ~~~
 !!! error TS2300: Duplicate identifier 'tsF'.
             static tgF() { }
             ~~~~~~
 !!! error TS1005: '{' expected.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tgF'.
             static get tgF()
                        ~~~
 !!! error TS2300: Duplicate identifier 'tgF'.
@@ -902,6 +1028,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public pF() { }
             private rF() { }
             public pgF() { }
+                   ~~~
+!!! error TS2300: Duplicate identifier 'pgF'.
             public get pgF()
                        ~~~
 !!! error TS2300: Duplicate identifier 'pgF'.
@@ -910,12 +1038,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public psF(param:any) { }
             ~~~~~~
 !!! error TS1005: '{' expected.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'psF'.
             public set psF(param:any)
                        ~~~
 !!! error TS2300: Duplicate identifier 'psF'.
             private rgF() { }
             ~~~~~~~
 !!! error TS1005: '{' expected.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rgF'.
             private get rgF()
                         ~~~
 !!! error TS2300: Duplicate identifier 'rgF'.
@@ -924,6 +1056,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             private rsF(param:any) { }
             ~~~~~~~
 !!! error TS1005: '{' expected.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rsF'.
             private set rsF(param:any)
                         ~~~
 !!! error TS2300: Duplicate identifier 'rsF'.
@@ -932,12 +1066,16 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
 !!! error TS1005: '{' expected.
             static tF() { }
             static tsF(param:any) { }
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tsF'.
             static set tsF(param:any)
                        ~~~
 !!! error TS2300: Duplicate identifier 'tsF'.
             static tgF() { }
             ~~~~~~
 !!! error TS1005: '{' expected.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tgF'.
             static get tgF()
                        ~~~
 !!! error TS2300: Duplicate identifier 'tgF'.
@@ -1031,6 +1169,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public pgF() { }
                          ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'pgF'.
             public get pgF()
                        ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1039,6 +1179,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             public psF(param:any) { }
                                   ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'psF'.
             public set psF(param:any)
                        ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1047,6 +1189,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             private rgF() { }
                           ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rgF'.
             private get rgF()
                         ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1055,6 +1199,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             private rsF(param:any) { }
                                    ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                    ~~~
+!!! error TS2300: Duplicate identifier 'rsF'.
             private set rsF(param:any)
                         ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1067,6 +1213,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             static tsF(param:any) { }
                                   ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tsF'.
             static set tsF(param:any)
                        ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1075,6 +1223,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
             static tgF() { }
                          ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                   ~~~
+!!! error TS2300: Duplicate identifier 'tgF'.
             static get tgF()
                        ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1121,6 +1271,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         public pgF() { }
                      ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+               ~~~
+!!! error TS2300: Duplicate identifier 'pgF'.
         public get pgF()
                    ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1129,6 +1281,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         public psF(param:any) { }
                               ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+               ~~~
+!!! error TS2300: Duplicate identifier 'psF'.
         public set psF(param:any)
                    ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1137,6 +1291,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         private rgF() { }
                       ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                ~~~
+!!! error TS2300: Duplicate identifier 'rgF'.
         private get rgF()
                     ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1145,6 +1301,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         private rsF(param:any) { }
                                ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+                ~~~
+!!! error TS2300: Duplicate identifier 'rsF'.
         private set rsF(param:any)
                     ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1157,6 +1315,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         static tsF(param:any) { }
                               ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+               ~~~
+!!! error TS2300: Duplicate identifier 'tsF'.
         static set tsF(param:any)
                    ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -1165,6 +1325,8 @@ tests/cases/compiler/giant.ts(668,9): error TS2386: Overload signatures must all
         static tgF() { }
                      ~
 !!! error TS1037: A function implementation cannot be declared in an ambient context.
+               ~~~
+!!! error TS2300: Duplicate identifier 'tgF'.
         static get tgF()
                    ~~~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
diff --git a/tests/baselines/reference/importAndVariableDeclarationConflict3.errors.txt b/tests/baselines/reference/importAndVariableDeclarationConflict3.errors.txt
index 739ca67724f..39567a11753 100644
--- a/tests/baselines/reference/importAndVariableDeclarationConflict3.errors.txt
+++ b/tests/baselines/reference/importAndVariableDeclarationConflict3.errors.txt
@@ -1,12 +1,15 @@
+tests/cases/compiler/importAndVariableDeclarationConflict3.ts(5,8): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/importAndVariableDeclarationConflict3.ts(6,8): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/compiler/importAndVariableDeclarationConflict3.ts (1 errors) ====
+==== tests/cases/compiler/importAndVariableDeclarationConflict3.ts (2 errors) ====
     module m {
       export var m = '';
     }
     
     import x = m.m;
+           ~
+!!! error TS2300: Duplicate identifier 'x'.
     import x = m.m;
            ~
 !!! error TS2300: Duplicate identifier 'x'.
diff --git a/tests/baselines/reference/interfaceDeclaration1.errors.txt b/tests/baselines/reference/interfaceDeclaration1.errors.txt
index a9654fabdcf..3d7fcb86784 100644
--- a/tests/baselines/reference/interfaceDeclaration1.errors.txt
+++ b/tests/baselines/reference/interfaceDeclaration1.errors.txt
@@ -1,4 +1,6 @@
+tests/cases/compiler/interfaceDeclaration1.ts(2,5): error TS2300: Duplicate identifier 'item'.
 tests/cases/compiler/interfaceDeclaration1.ts(3,5): error TS2300: Duplicate identifier 'item'.
+tests/cases/compiler/interfaceDeclaration1.ts(7,5): error TS2300: Duplicate identifier 'item'.
 tests/cases/compiler/interfaceDeclaration1.ts(8,5): error TS2300: Duplicate identifier 'item'.
 tests/cases/compiler/interfaceDeclaration1.ts(22,11): error TS2310: Type 'I5' recursively references itself as a base type.
 tests/cases/compiler/interfaceDeclaration1.ts(35,7): error TS2421: Class 'C1' incorrectly implements interface 'I3':
@@ -8,9 +10,11 @@ tests/cases/compiler/interfaceDeclaration1.ts(52,11): error TS2320: Interface 'i
   Named properties 'foo' of types 'i10' and 'i11' are not identical.
 
 
-==== tests/cases/compiler/interfaceDeclaration1.ts (6 errors) ====
+==== tests/cases/compiler/interfaceDeclaration1.ts (8 errors) ====
     interface I1 {
         item:number;
+        ~~~~
+!!! error TS2300: Duplicate identifier 'item'.
         item:number;
         ~~~~
 !!! error TS2300: Duplicate identifier 'item'.
@@ -18,6 +22,8 @@ tests/cases/compiler/interfaceDeclaration1.ts(52,11): error TS2320: Interface 'i
     
     interface I2 {
         item:any;
+        ~~~~
+!!! error TS2300: Duplicate identifier 'item'.
         item:number;
         ~~~~
 !!! error TS2300: Duplicate identifier 'item'.
diff --git a/tests/baselines/reference/interfaceDeclaration2.errors.txt b/tests/baselines/reference/interfaceDeclaration2.errors.txt
index 8ef5e1a40d7..9739d946bc5 100644
--- a/tests/baselines/reference/interfaceDeclaration2.errors.txt
+++ b/tests/baselines/reference/interfaceDeclaration2.errors.txt
@@ -1,11 +1,14 @@
+tests/cases/compiler/interfaceDeclaration2.ts(4,11): error TS2300: Duplicate identifier 'I2'.
 tests/cases/compiler/interfaceDeclaration2.ts(5,7): error TS2300: Duplicate identifier 'I2'.
 
 
-==== tests/cases/compiler/interfaceDeclaration2.ts (1 errors) ====
+==== tests/cases/compiler/interfaceDeclaration2.ts (2 errors) ====
     interface I1 { }
     module I1 { }
     
     interface I2 { }
+              ~~
+!!! error TS2300: Duplicate identifier 'I2'.
     class I2 { }
           ~~
 !!! error TS2300: Duplicate identifier 'I2'.
diff --git a/tests/baselines/reference/invalidInstantiatedModule.errors.txt b/tests/baselines/reference/invalidInstantiatedModule.errors.txt
index e6cb5491407..5a8ac069803 100644
--- a/tests/baselines/reference/invalidInstantiatedModule.errors.txt
+++ b/tests/baselines/reference/invalidInstantiatedModule.errors.txt
@@ -1,10 +1,13 @@
+tests/cases/conformance/internalModules/moduleDeclarations/invalidInstantiatedModule.ts(2,18): error TS2300: Duplicate identifier 'Point'.
 tests/cases/conformance/internalModules/moduleDeclarations/invalidInstantiatedModule.ts(3,16): error TS2300: Duplicate identifier 'Point'.
 tests/cases/conformance/internalModules/moduleDeclarations/invalidInstantiatedModule.ts(12,8): error TS2304: Cannot find name 'm'.
 
 
-==== tests/cases/conformance/internalModules/moduleDeclarations/invalidInstantiatedModule.ts (2 errors) ====
+==== tests/cases/conformance/internalModules/moduleDeclarations/invalidInstantiatedModule.ts (3 errors) ====
     module M {
         export class Point { x: number; y: number }
+                     ~~~~~
+!!! error TS2300: Duplicate identifier 'Point'.
         export var Point = 1;  // Error
                    ~~~~~
 !!! error TS2300: Duplicate identifier 'Point'.
diff --git a/tests/baselines/reference/invalidNestedModules.errors.txt b/tests/baselines/reference/invalidNestedModules.errors.txt
index 1d7e2641ff4..972c177fc0e 100644
--- a/tests/baselines/reference/invalidNestedModules.errors.txt
+++ b/tests/baselines/reference/invalidNestedModules.errors.txt
@@ -1,8 +1,9 @@
 tests/cases/conformance/internalModules/moduleDeclarations/invalidNestedModules.ts(1,12): error TS2434: A module declaration cannot be located prior to a class or function with which it is merged
+tests/cases/conformance/internalModules/moduleDeclarations/invalidNestedModules.ts(17,18): error TS2300: Duplicate identifier 'Point'.
 tests/cases/conformance/internalModules/moduleDeclarations/invalidNestedModules.ts(24,20): error TS2300: Duplicate identifier 'Point'.
 
 
-==== tests/cases/conformance/internalModules/moduleDeclarations/invalidNestedModules.ts (2 errors) ====
+==== tests/cases/conformance/internalModules/moduleDeclarations/invalidNestedModules.ts (3 errors) ====
     module A.B.C {
                ~
 !!! error TS2434: A module declaration cannot be located prior to a class or function with which it is merged
@@ -22,6 +23,8 @@ tests/cases/conformance/internalModules/moduleDeclarations/invalidNestedModules.
     
     module M2.X {
         export class Point {
+                     ~~~~~
+!!! error TS2300: Duplicate identifier 'Point'.
             x: number; y: number;
         }
     }
diff --git a/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt b/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt
index 1bc749ba399..39e5cfaa834 100644
--- a/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt
+++ b/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt
@@ -1,13 +1,15 @@
+tests/cases/compiler/lastPropertyInLiteralWins.ts(8,5): error TS2300: Duplicate identifier 'thunk'.
 tests/cases/compiler/lastPropertyInLiteralWins.ts(9,5): error TS2300: Duplicate identifier 'thunk'.
 tests/cases/compiler/lastPropertyInLiteralWins.ts(12,6): error TS2345: Argument of type '{ thunk: (num: number) => void; }' is not assignable to parameter of type 'Thing'.
   Types of property 'thunk' are incompatible:
     Type '(num: number) => void' is not assignable to type '(str: string) => void':
       Types of parameters 'num' and 'str' are incompatible:
         Type 'number' is not assignable to type 'string'.
+tests/cases/compiler/lastPropertyInLiteralWins.ts(13,5): error TS2300: Duplicate identifier 'thunk'.
 tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2300: Duplicate identifier 'thunk'.
 
 
-==== tests/cases/compiler/lastPropertyInLiteralWins.ts (3 errors) ====
+==== tests/cases/compiler/lastPropertyInLiteralWins.ts (5 errors) ====
     interface Thing {
         thunk: (str: string) => void;
     }
@@ -16,6 +18,8 @@ tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2300: Duplicate
     }
     test({ // Should error, as last one wins, and is wrong type
         thunk: (str: string) => {},
+        ~~~~~
+!!! error TS2300: Duplicate identifier 'thunk'.
         thunk: (num: number) => {}
         ~~~~~
 !!! error TS2300: Duplicate identifier 'thunk'.
@@ -25,6 +29,8 @@ tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2300: Duplicate
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         thunk: (num: number) => {},
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+        ~~~~~
+!!! error TS2300: Duplicate identifier 'thunk'.
         thunk: (str: string) => {}
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         ~~~~~
diff --git a/tests/baselines/reference/memberOverride.errors.txt b/tests/baselines/reference/memberOverride.errors.txt
index 5cc005b7339..c63803f5aa1 100644
--- a/tests/baselines/reference/memberOverride.errors.txt
+++ b/tests/baselines/reference/memberOverride.errors.txt
@@ -1,12 +1,15 @@
+tests/cases/compiler/memberOverride.ts(4,5): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/memberOverride.ts(5,5): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/memberOverride.ts(8,5): error TS2323: Type 'string' is not assignable to type 'number'.
 
 
-==== tests/cases/compiler/memberOverride.ts (2 errors) ====
+==== tests/cases/compiler/memberOverride.ts (3 errors) ====
     // An object initialiser accepts the first definition for the same property with a different type signature
     // Should compile, since the second declaration of a overrides the first
     var x = {
         a: "", 
+        ~
+!!! error TS2300: Duplicate identifier 'a'.
         a: 5
         ~
 !!! error TS2300: Duplicate identifier 'a'.
diff --git a/tests/baselines/reference/mergedInterfacesWithConflictingPropertyNames.errors.txt b/tests/baselines/reference/mergedInterfacesWithConflictingPropertyNames.errors.txt
index 28aa8fa4be8..0b5984dcc6d 100644
--- a/tests/baselines/reference/mergedInterfacesWithConflictingPropertyNames.errors.txt
+++ b/tests/baselines/reference/mergedInterfacesWithConflictingPropertyNames.errors.txt
@@ -1,11 +1,16 @@
+tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames.ts(2,5): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames.ts(6,5): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames.ts(11,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames.ts(15,9): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames.ts(33,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames.ts(39,9): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames.ts (3 errors) ====
+==== tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames.ts (6 errors) ====
     interface A {
         x: string; // error
+        ~
+!!! error TS2300: Duplicate identifier 'x'.
     }
     
     interface A {
@@ -17,6 +22,8 @@ tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConfli
     module M {
         interface A<T> {
             x: T;
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
         }
     
         interface A<T> {
@@ -41,6 +48,8 @@ tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConfli
     module M3 {
         export interface A<T> {
             x: T;
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
         }
     }
     
diff --git a/tests/baselines/reference/mergedInterfacesWithConflictingPropertyNames2.errors.txt b/tests/baselines/reference/mergedInterfacesWithConflictingPropertyNames2.errors.txt
index 74b6c39b1f7..d0a50f4ae69 100644
--- a/tests/baselines/reference/mergedInterfacesWithConflictingPropertyNames2.errors.txt
+++ b/tests/baselines/reference/mergedInterfacesWithConflictingPropertyNames2.errors.txt
@@ -1,11 +1,16 @@
+tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames2.ts(2,5): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames2.ts(6,5): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames2.ts(11,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames2.ts(15,9): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames2.ts(33,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames2.ts(39,9): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames2.ts (3 errors) ====
+==== tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConflictingPropertyNames2.ts (6 errors) ====
     interface A {
         x: string; // error
+        ~
+!!! error TS2300: Duplicate identifier 'x'.
     }
     
     interface A {
@@ -17,6 +22,8 @@ tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConfli
     module M {
         interface A<T> {
             x: T;
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
         }
     
         interface A<T> {
@@ -41,6 +48,8 @@ tests/cases/conformance/interfaces/declarationMerging/mergedInterfacesWithConfli
     module M3 {
         export interface A<T> {
             x: T;
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
         }
     }
     
diff --git a/tests/baselines/reference/mismatchedClassConstructorVariable.errors.txt b/tests/baselines/reference/mismatchedClassConstructorVariable.errors.txt
index e294d8fbc72..8c81f7e34c8 100644
--- a/tests/baselines/reference/mismatchedClassConstructorVariable.errors.txt
+++ b/tests/baselines/reference/mismatchedClassConstructorVariable.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/mismatchedClassConstructorVariable.ts(1,5): error TS2300: Duplicate identifier 'baz'.
 tests/cases/compiler/mismatchedClassConstructorVariable.ts(2,7): error TS2300: Duplicate identifier 'baz'.
 
 
-==== tests/cases/compiler/mismatchedClassConstructorVariable.ts (1 errors) ====
+==== tests/cases/compiler/mismatchedClassConstructorVariable.ts (2 errors) ====
     var baz: foo;
+        ~~~
+!!! error TS2300: Duplicate identifier 'baz'.
     class baz { }
           ~~~
 !!! error TS2300: Duplicate identifier 'baz'.
diff --git a/tests/baselines/reference/module_augmentExistingAmbientVariable.errors.txt b/tests/baselines/reference/module_augmentExistingAmbientVariable.errors.txt
index 6174a6a95db..564da071648 100644
--- a/tests/baselines/reference/module_augmentExistingAmbientVariable.errors.txt
+++ b/tests/baselines/reference/module_augmentExistingAmbientVariable.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/module_augmentExistingAmbientVariable.ts(1,13): error TS2300: Duplicate identifier 'console'.
 tests/cases/compiler/module_augmentExistingAmbientVariable.ts(3,8): error TS2300: Duplicate identifier 'console'.
 
 
-==== tests/cases/compiler/module_augmentExistingAmbientVariable.ts (1 errors) ====
+==== tests/cases/compiler/module_augmentExistingAmbientVariable.ts (2 errors) ====
     declare var console: any;
+                ~~~~~~~
+!!! error TS2300: Duplicate identifier 'console'.
     
     module console {
            ~~~~~~~
diff --git a/tests/baselines/reference/module_augmentExistingVariable.errors.txt b/tests/baselines/reference/module_augmentExistingVariable.errors.txt
index a829d094819..f1d17894077 100644
--- a/tests/baselines/reference/module_augmentExistingVariable.errors.txt
+++ b/tests/baselines/reference/module_augmentExistingVariable.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/module_augmentExistingVariable.ts(1,5): error TS2300: Duplicate identifier 'console'.
 tests/cases/compiler/module_augmentExistingVariable.ts(3,8): error TS2300: Duplicate identifier 'console'.
 
 
-==== tests/cases/compiler/module_augmentExistingVariable.ts (1 errors) ====
+==== tests/cases/compiler/module_augmentExistingVariable.ts (2 errors) ====
     var console: any;
+        ~~~~~~~
+!!! error TS2300: Duplicate identifier 'console'.
     
     module console {
            ~~~~~~~
diff --git a/tests/baselines/reference/nameCollisions.errors.txt b/tests/baselines/reference/nameCollisions.errors.txt
index b587d842c6f..baa7c6cbfd5 100644
--- a/tests/baselines/reference/nameCollisions.errors.txt
+++ b/tests/baselines/reference/nameCollisions.errors.txt
@@ -1,17 +1,27 @@
+tests/cases/compiler/nameCollisions.ts(2,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/nameCollisions.ts(4,12): error TS2300: Duplicate identifier 'x'.
+tests/cases/compiler/nameCollisions.ts(10,12): error TS2300: Duplicate identifier 'z'.
 tests/cases/compiler/nameCollisions.ts(13,9): error TS2300: Duplicate identifier 'z'.
 tests/cases/compiler/nameCollisions.ts(15,12): error TS2434: A module declaration cannot be located prior to a class or function with which it is merged
+tests/cases/compiler/nameCollisions.ts(24,9): error TS2300: Duplicate identifier 'f'.
 tests/cases/compiler/nameCollisions.ts(25,14): error TS2300: Duplicate identifier 'f'.
+tests/cases/compiler/nameCollisions.ts(27,14): error TS2300: Duplicate identifier 'f2'.
 tests/cases/compiler/nameCollisions.ts(28,9): error TS2300: Duplicate identifier 'f2'.
+tests/cases/compiler/nameCollisions.ts(33,11): error TS2300: Duplicate identifier 'C'.
 tests/cases/compiler/nameCollisions.ts(34,14): error TS2300: Duplicate identifier 'C'.
+tests/cases/compiler/nameCollisions.ts(36,14): error TS2300: Duplicate identifier 'C2'.
 tests/cases/compiler/nameCollisions.ts(37,11): error TS2300: Duplicate identifier 'C2'.
+tests/cases/compiler/nameCollisions.ts(42,11): error TS2300: Duplicate identifier 'cli'.
 tests/cases/compiler/nameCollisions.ts(43,15): error TS2300: Duplicate identifier 'cli'.
+tests/cases/compiler/nameCollisions.ts(45,15): error TS2300: Duplicate identifier 'cli2'.
 tests/cases/compiler/nameCollisions.ts(46,11): error TS2300: Duplicate identifier 'cli2'.
 
 
-==== tests/cases/compiler/nameCollisions.ts (9 errors) ====
+==== tests/cases/compiler/nameCollisions.ts (17 errors) ====
     module T {
         var x = 2;
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
     
         module x { // error
                ~
@@ -22,6 +32,8 @@ tests/cases/compiler/nameCollisions.ts(46,11): error TS2300: Duplicate identifie
         }
     
         module z {
+               ~
+!!! error TS2300: Duplicate identifier 'z'.
             var t;
         }
         var z; // error
@@ -40,11 +52,15 @@ tests/cases/compiler/nameCollisions.ts(46,11): error TS2300: Duplicate identifie
         module w { } //ok
     
         var f;
+            ~
+!!! error TS2300: Duplicate identifier 'f'.
         function f() { } //error
                  ~
 !!! error TS2300: Duplicate identifier 'f'.
     
         function f2() { }
+                 ~~
+!!! error TS2300: Duplicate identifier 'f2'.
         var f2; // error
             ~~
 !!! error TS2300: Duplicate identifier 'f2'.
@@ -53,11 +69,15 @@ tests/cases/compiler/nameCollisions.ts(46,11): error TS2300: Duplicate identifie
         interface i { } //ok
     
         class C { }
+              ~
+!!! error TS2300: Duplicate identifier 'C'.
         function C() { } // error
                  ~
 !!! error TS2300: Duplicate identifier 'C'.
     
         function C2() { }
+                 ~~
+!!! error TS2300: Duplicate identifier 'C2'.
         class C2 { } // error
               ~~
 !!! error TS2300: Duplicate identifier 'C2'.
@@ -66,11 +86,15 @@ tests/cases/compiler/nameCollisions.ts(46,11): error TS2300: Duplicate identifie
         interface fi { } // ok
     
         class cli { }
+              ~~~
+!!! error TS2300: Duplicate identifier 'cli'.
         interface cli { } // error
                   ~~~
 !!! error TS2300: Duplicate identifier 'cli'.
     
         interface cli2 { }
+                  ~~~~
+!!! error TS2300: Duplicate identifier 'cli2'.
         class cli2 { } // error
               ~~~~
 !!! error TS2300: Duplicate identifier 'cli2'.
diff --git a/tests/baselines/reference/numericClassMembers1.errors.txt b/tests/baselines/reference/numericClassMembers1.errors.txt
index 28c06a6fcf5..eb99f26bb4c 100644
--- a/tests/baselines/reference/numericClassMembers1.errors.txt
+++ b/tests/baselines/reference/numericClassMembers1.errors.txt
@@ -1,10 +1,14 @@
+tests/cases/compiler/numericClassMembers1.ts(2,3): error TS2300: Duplicate identifier '0'.
 tests/cases/compiler/numericClassMembers1.ts(3,3): error TS2300: Duplicate identifier '0.0'.
+tests/cases/compiler/numericClassMembers1.ts(7,3): error TS2300: Duplicate identifier '0.0'.
 tests/cases/compiler/numericClassMembers1.ts(8,2): error TS2300: Duplicate identifier ''0''.
 
 
-==== tests/cases/compiler/numericClassMembers1.ts (2 errors) ====
+==== tests/cases/compiler/numericClassMembers1.ts (4 errors) ====
     class C234 {
       0 = 1; 
+      ~
+!!! error TS2300: Duplicate identifier '0'.
       0.0 = 2;
       ~~~
 !!! error TS2300: Duplicate identifier '0.0'.
@@ -12,6 +16,8 @@ tests/cases/compiler/numericClassMembers1.ts(8,2): error TS2300: Duplicate ident
      
     class C235 { 
       0.0 = 1;
+      ~~~
+!!! error TS2300: Duplicate identifier '0.0'.
      '0' = 2;
      ~~~
 !!! error TS2300: Duplicate identifier ''0''.
diff --git a/tests/baselines/reference/numericNamedPropertyDuplicates.errors.txt b/tests/baselines/reference/numericNamedPropertyDuplicates.errors.txt
index d3192f8e3c5..c5890d7c98c 100644
--- a/tests/baselines/reference/numericNamedPropertyDuplicates.errors.txt
+++ b/tests/baselines/reference/numericNamedPropertyDuplicates.errors.txt
@@ -1,18 +1,27 @@
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(20,5): error TS1005: ',' expected.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(2,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(3,5): error TS2300: Duplicate identifier '1.0'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(4,12): error TS2300: Duplicate identifier '2'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(5,12): error TS2300: Duplicate identifier '2'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(9,5): error TS2300: Duplicate identifier '2'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(10,5): error TS2300: Duplicate identifier '2.'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(14,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(15,5): error TS2300: Duplicate identifier '1'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(19,5): error TS2300: Duplicate identifier '2'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts(20,5): error TS2300: Duplicate identifier '2'.
 
 
-==== tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts (6 errors) ====
+==== tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedPropertyDuplicates.ts (11 errors) ====
     class C {
         1: number;
+        ~
+!!! error TS2300: Duplicate identifier '1'.
         1.0: number;
         ~~~
 !!! error TS2300: Duplicate identifier '1.0'.
         static 2: number;
+               ~
+!!! error TS2300: Duplicate identifier '2'.
         static 2: number;
                ~
 !!! error TS2300: Duplicate identifier '2'.
@@ -20,6 +29,8 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedP
     
     interface I {
         2: number;
+        ~
+!!! error TS2300: Duplicate identifier '2'.
         2.: number;
         ~~
 !!! error TS2300: Duplicate identifier '2.'.
@@ -27,6 +38,8 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedP
     
     var a: {
         1: number;
+        ~
+!!! error TS2300: Duplicate identifier '1'.
         1: number;
         ~
 !!! error TS2300: Duplicate identifier '1'.
@@ -34,6 +47,8 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericNamedP
     
     var b = {
         2: 1
+        ~
+!!! error TS2300: Duplicate identifier '2'.
         2: 1
         ~
 !!! error TS1005: ',' expected.
diff --git a/tests/baselines/reference/numericStringNamedPropertyEquivalence.errors.txt b/tests/baselines/reference/numericStringNamedPropertyEquivalence.errors.txt
index 9ce36b4937c..4ebef99bd07 100644
--- a/tests/baselines/reference/numericStringNamedPropertyEquivalence.errors.txt
+++ b/tests/baselines/reference/numericStringNamedPropertyEquivalence.errors.txt
@@ -1,14 +1,20 @@
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(4,5): error TS2300: Duplicate identifier '"1"'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(6,5): error TS2300: Duplicate identifier '1.0'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(10,5): error TS2300: Duplicate identifier '"1"'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(12,5): error TS2300: Duplicate identifier '1'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(16,5): error TS2300: Duplicate identifier '"1"'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(17,5): error TS2300: Duplicate identifier '1.0'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(21,5): error TS2300: Duplicate identifier '"0"'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts(22,5): error TS2300: Duplicate identifier '0'.
 
 
-==== tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts (4 errors) ====
+==== tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericStringNamedPropertyEquivalence.ts (8 errors) ====
     // Each of these types has an error in it. 
     // String named and numeric named properties conflict if they would be equivalent after ToNumber on the property name.
     class C {
         "1": number;
+        ~~~
+!!! error TS2300: Duplicate identifier '"1"'.
         "1.0": number; // not a duplicate
         1.0: number;
         ~~~
@@ -17,6 +23,8 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericString
     
     interface I {
         "1": number;
+        ~~~
+!!! error TS2300: Duplicate identifier '"1"'.
         "1.": number; // not a duplicate
         1: number;
         ~
@@ -25,6 +33,8 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericString
     
     var a: {
         "1": number;
+        ~~~
+!!! error TS2300: Duplicate identifier '"1"'.
         1.0: string;
         ~~~
 !!! error TS2300: Duplicate identifier '1.0'.
@@ -32,6 +42,8 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/numericString
     
     var b = {
         "0": '',
+        ~~~
+!!! error TS2300: Duplicate identifier '"0"'.
         0: ''
         ~
 !!! error TS2300: Duplicate identifier '0'.
diff --git a/tests/baselines/reference/objectLiteralErrors.errors.txt b/tests/baselines/reference/objectLiteralErrors.errors.txt
index 367043a53ef..1fc92ac5a48 100644
--- a/tests/baselines/reference/objectLiteralErrors.errors.txt
+++ b/tests/baselines/reference/objectLiteralErrors.errors.txt
@@ -18,41 +18,77 @@ tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(37,23)
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(38,27): error TS1119: An object literal cannot have property and accessor with the same name.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(39,26): error TS1119: An object literal cannot have property and accessor with the same name.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(40,46): error TS1119: An object literal cannot have property and accessor with the same name.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(3,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(3,18): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(4,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(4,19): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(5,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(5,18): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(6,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(6,21): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(7,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(7,19): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(8,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(8,18): error TS2300: Duplicate identifier ''a''.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(9,12): error TS2300: Duplicate identifier ''a''.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(9,20): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(10,12): error TS2300: Duplicate identifier ''a''.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(10,20): error TS2300: Duplicate identifier '"a"'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(11,12): error TS2300: Duplicate identifier ''a''.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(11,20): error TS2300: Duplicate identifier ''a''.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(12,13): error TS2300: Duplicate identifier '"a"'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(12,21): error TS2300: Duplicate identifier ''a''.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(13,13): error TS2300: Duplicate identifier '1.0'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(13,21): error TS2300: Duplicate identifier ''1''.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(14,13): error TS2300: Duplicate identifier '0'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(14,19): error TS2300: Duplicate identifier '0'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(15,13): error TS2300: Duplicate identifier '0'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(15,19): error TS2300: Duplicate identifier '0'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(16,13): error TS2300: Duplicate identifier '0'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(16,19): error TS2300: Duplicate identifier '0x0'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(17,13): error TS2300: Duplicate identifier '0'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(17,19): error TS2300: Duplicate identifier '000'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(18,13): error TS2300: Duplicate identifier '"100"'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(18,23): error TS2300: Duplicate identifier '1e2'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(19,13): error TS2300: Duplicate identifier '0x20'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(19,22): error TS2300: Duplicate identifier '3.2e1'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(20,13): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(20,25): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(23,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(23,22): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(24,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(24,23): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(25,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(25,22): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(26,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(26,25): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(27,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(27,23): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(28,12): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(28,22): error TS2300: Duplicate identifier ''a''.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(29,12): error TS2300: Duplicate identifier ''a''.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(29,24): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(30,12): error TS2300: Duplicate identifier ''a''.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(30,24): error TS2300: Duplicate identifier '"a"'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(31,12): error TS2300: Duplicate identifier ''a''.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(31,24): error TS2300: Duplicate identifier ''a''.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(32,13): error TS2300: Duplicate identifier '"a"'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(32,25): error TS2300: Duplicate identifier ''a''.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(33,13): error TS2300: Duplicate identifier '1.0'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(33,25): error TS2300: Duplicate identifier ''1''.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(34,13): error TS2300: Duplicate identifier '0'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(34,23): error TS2300: Duplicate identifier '0'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(35,13): error TS2300: Duplicate identifier '0'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(35,23): error TS2300: Duplicate identifier '0'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(36,13): error TS2300: Duplicate identifier '0'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(36,23): error TS2300: Duplicate identifier '0x0'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(37,13): error TS2300: Duplicate identifier '0'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(37,23): error TS2300: Duplicate identifier '000'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(38,13): error TS2300: Duplicate identifier '"100"'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(38,27): error TS2300: Duplicate identifier '1e2'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(39,13): error TS2300: Duplicate identifier '0x20'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(39,26): error TS2300: Duplicate identifier '3.2e1'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(40,13): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(40,46): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(43,12): error TS2380: 'get' and 'set' accessor must have the same type.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(43,43): error TS2380: 'get' and 'set' accessor must have the same type.
@@ -61,63 +97,99 @@ tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(45,12)
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(45,51): error TS2380: 'get' and 'set' accessor must have the same type.
 
 
-==== tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts (61 errors) ====
+==== tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts (97 errors) ====
     
     // Multiple properties with the same name
     var e1 = { a: 0, a: 0 };
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                      ~
 !!! error TS2300: Duplicate identifier 'a'.
     var e2 = { a: '', a: '' };
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                       ~
 !!! error TS2300: Duplicate identifier 'a'.
     var e3 = { a: 0, a: '' };
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                      ~
 !!! error TS2300: Duplicate identifier 'a'.
     var e4 = { a: true, a: false };
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                         ~
 !!! error TS2300: Duplicate identifier 'a'.
     var e5 = { a: {}, a: {} };
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                       ~
 !!! error TS2300: Duplicate identifier 'a'.
     var e6 = { a: 0, 'a': 0 };
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                      ~~~
 !!! error TS2300: Duplicate identifier ''a''.
     var e7 = { 'a': 0, a: 0 };
+               ~~~
+!!! error TS2300: Duplicate identifier ''a''.
                        ~
 !!! error TS2300: Duplicate identifier 'a'.
     var e8 = { 'a': 0, "a": 0 };
+               ~~~
+!!! error TS2300: Duplicate identifier ''a''.
                        ~~~
 !!! error TS2300: Duplicate identifier '"a"'.
     var e9 = { 'a': 0, 'a': 0 };
+               ~~~
+!!! error TS2300: Duplicate identifier ''a''.
                        ~~~
 !!! error TS2300: Duplicate identifier ''a''.
     var e10 = { "a": 0, 'a': 0 };
+                ~~~
+!!! error TS2300: Duplicate identifier '"a"'.
                         ~~~
 !!! error TS2300: Duplicate identifier ''a''.
     var e11 = { 1.0: 0, '1': 0 };
+                ~~~
+!!! error TS2300: Duplicate identifier '1.0'.
                         ~~~
 !!! error TS2300: Duplicate identifier ''1''.
     var e12 = { 0: 0, 0: 0 };
+                ~
+!!! error TS2300: Duplicate identifier '0'.
                       ~
 !!! error TS2300: Duplicate identifier '0'.
     var e13 = { 0: 0, 0: 0 };
+                ~
+!!! error TS2300: Duplicate identifier '0'.
                       ~
 !!! error TS2300: Duplicate identifier '0'.
     var e14 = { 0: 0, 0x0: 0 };
+                ~
+!!! error TS2300: Duplicate identifier '0'.
                       ~~~
 !!! error TS2300: Duplicate identifier '0x0'.
     var e14 = { 0: 0, 000: 0 };
                       ~~~
 !!! error TS1085: Octal literals are not available when targeting ECMAScript 5 and higher.
+                ~
+!!! error TS2300: Duplicate identifier '0'.
                       ~~~
 !!! error TS2300: Duplicate identifier '000'.
     var e15 = { "100": 0, 1e2: 0 };
+                ~~~~~
+!!! error TS2300: Duplicate identifier '"100"'.
                           ~~~
 !!! error TS2300: Duplicate identifier '1e2'.
     var e16 = { 0x20: 0, 3.2e1: 0 };
+                ~~~~
+!!! error TS2300: Duplicate identifier '0x20'.
                          ~~~~~
 !!! error TS2300: Duplicate identifier '3.2e1'.
     var e17 = { a: 0, b: 1, a: 0 };
+                ~
+!!! error TS2300: Duplicate identifier 'a'.
                             ~
 !!! error TS2300: Duplicate identifier 'a'.
     
@@ -125,71 +197,99 @@ tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(45,51)
     var f1 = { a: 0, get a() { return 0; } };
                          ~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                          ~
 !!! error TS2300: Duplicate identifier 'a'.
     var f2 = { a: '', get a() { return ''; } };
                           ~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                           ~
 !!! error TS2300: Duplicate identifier 'a'.
     var f3 = { a: 0, get a() { return ''; } };
                          ~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                          ~
 !!! error TS2300: Duplicate identifier 'a'.
     var f4 = { a: true, get a() { return false; } };
                             ~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                             ~
 !!! error TS2300: Duplicate identifier 'a'.
     var f5 = { a: {}, get a() { return {}; } };
                           ~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                           ~
 !!! error TS2300: Duplicate identifier 'a'.
     var f6 = { a: 0, get 'a'() { return 0; } };
                          ~~~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+               ~
+!!! error TS2300: Duplicate identifier 'a'.
                          ~~~
 !!! error TS2300: Duplicate identifier ''a''.
     var f7 = { 'a': 0, get a() { return 0; } };
                            ~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+               ~~~
+!!! error TS2300: Duplicate identifier ''a''.
                            ~
 !!! error TS2300: Duplicate identifier 'a'.
     var f8 = { 'a': 0, get "a"() { return 0; } };
                            ~~~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+               ~~~
+!!! error TS2300: Duplicate identifier ''a''.
                            ~~~
 !!! error TS2300: Duplicate identifier '"a"'.
     var f9 = { 'a': 0, get 'a'() { return 0; } };
                            ~~~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+               ~~~
+!!! error TS2300: Duplicate identifier ''a''.
                            ~~~
 !!! error TS2300: Duplicate identifier ''a''.
     var f10 = { "a": 0, get 'a'() { return 0; } };
                             ~~~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+                ~~~
+!!! error TS2300: Duplicate identifier '"a"'.
                             ~~~
 !!! error TS2300: Duplicate identifier ''a''.
     var f11 = { 1.0: 0, get '1'() { return 0; } };
                             ~~~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+                ~~~
+!!! error TS2300: Duplicate identifier '1.0'.
                             ~~~
 !!! error TS2300: Duplicate identifier ''1''.
     var f12 = { 0: 0, get 0() { return 0; } };
                           ~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+                ~
+!!! error TS2300: Duplicate identifier '0'.
                           ~
 !!! error TS2300: Duplicate identifier '0'.
     var f13 = { 0: 0, get 0() { return 0; } };
                           ~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+                ~
+!!! error TS2300: Duplicate identifier '0'.
                           ~
 !!! error TS2300: Duplicate identifier '0'.
     var f14 = { 0: 0, get 0x0() { return 0; } };
                           ~~~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+                ~
+!!! error TS2300: Duplicate identifier '0'.
                           ~~~
 !!! error TS2300: Duplicate identifier '0x0'.
     var f14 = { 0: 0, get 000() { return 0; } };
@@ -197,21 +297,29 @@ tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(45,51)
 !!! error TS1085: Octal literals are not available when targeting ECMAScript 5 and higher.
                           ~~~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+                ~
+!!! error TS2300: Duplicate identifier '0'.
                           ~~~
 !!! error TS2300: Duplicate identifier '000'.
     var f15 = { "100": 0, get 1e2() { return 0; } };
                               ~~~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+                ~~~~~
+!!! error TS2300: Duplicate identifier '"100"'.
                               ~~~
 !!! error TS2300: Duplicate identifier '1e2'.
     var f16 = { 0x20: 0, get 3.2e1() { return 0; } };
                              ~~~~~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+                ~~~~
+!!! error TS2300: Duplicate identifier '0x20'.
                              ~~~~~
 !!! error TS2300: Duplicate identifier '3.2e1'.
     var f17 = { a: 0, get b() { return 1; }, get a() { return 0; } };
                                                  ~
 !!! error TS1119: An object literal cannot have property and accessor with the same name.
+                ~
+!!! error TS2300: Duplicate identifier 'a'.
                                                  ~
 !!! error TS2300: Duplicate identifier 'a'.
     
diff --git a/tests/baselines/reference/objectTypeWithDuplicateNumericProperty.errors.txt b/tests/baselines/reference/objectTypeWithDuplicateNumericProperty.errors.txt
index 122304d1497..c89cd04d1ee 100644
--- a/tests/baselines/reference/objectTypeWithDuplicateNumericProperty.errors.txt
+++ b/tests/baselines/reference/objectTypeWithDuplicateNumericProperty.errors.txt
@@ -1,23 +1,29 @@
+tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(5,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(6,5): error TS2300: Duplicate identifier '1.0'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(7,5): error TS2300: Duplicate identifier '1.'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(8,5): error TS2300: Duplicate identifier '1.00'.
+tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(12,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(13,5): error TS2300: Duplicate identifier '1.0'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(14,5): error TS2300: Duplicate identifier '1.'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(15,5): error TS2300: Duplicate identifier '1.00'.
+tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(19,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(20,5): error TS2300: Duplicate identifier '1.0'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(21,5): error TS2300: Duplicate identifier '1.'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(22,5): error TS2300: Duplicate identifier '1.00'.
+tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(26,5): error TS2300: Duplicate identifier '1'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(27,5): error TS2300: Duplicate identifier '1.0'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(28,5): error TS2300: Duplicate identifier '1.'.
 tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(29,5): error TS2300: Duplicate identifier '1.00'.
 
 
-==== tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts (12 errors) ====
+==== tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts (16 errors) ====
     // numeric properties must be distinct after a ToNumber operation
     // so the below are all errors
     
     class C {
         1;
+        ~
+!!! error TS2300: Duplicate identifier '1'.
         1.0;
         ~~~
 !!! error TS2300: Duplicate identifier '1.0'.
@@ -31,6 +37,8 @@ tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(
     
     interface I {
         1;
+        ~
+!!! error TS2300: Duplicate identifier '1'.
         1.0;
         ~~~
 !!! error TS2300: Duplicate identifier '1.0'.
@@ -44,6 +52,8 @@ tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(
     
     var a: {
         1;
+        ~
+!!! error TS2300: Duplicate identifier '1'.
         1.0;
         ~~~
 !!! error TS2300: Duplicate identifier '1.0'.
@@ -57,6 +67,8 @@ tests/cases/conformance/types/members/objectTypeWithDuplicateNumericProperty.ts(
     
     var b = {
         1: 1,
+        ~
+!!! error TS2300: Duplicate identifier '1'.
         1.0: 1,
         ~~~
 !!! error TS2300: Duplicate identifier '1.0'.
diff --git a/tests/baselines/reference/optionalParamArgsTest.errors.txt b/tests/baselines/reference/optionalParamArgsTest.errors.txt
index ed46bfd3344..a8ce88e494e 100644
--- a/tests/baselines/reference/optionalParamArgsTest.errors.txt
+++ b/tests/baselines/reference/optionalParamArgsTest.errors.txt
@@ -1,5 +1,6 @@
 tests/cases/compiler/optionalParamArgsTest.ts(35,47): error TS1016: A required parameter cannot follow an optional parameter.
-tests/cases/compiler/optionalParamArgsTest.ts(35,5): error TS2393: Duplicate function implementation.
+tests/cases/compiler/optionalParamArgsTest.ts(31,12): error TS2393: Duplicate function implementation.
+tests/cases/compiler/optionalParamArgsTest.ts(35,12): error TS2393: Duplicate function implementation.
 tests/cases/compiler/optionalParamArgsTest.ts(99,1): error TS2346: Supplied parameters do not match any signature of call target.
 tests/cases/compiler/optionalParamArgsTest.ts(100,1): error TS2346: Supplied parameters do not match any signature of call target.
 tests/cases/compiler/optionalParamArgsTest.ts(101,1): error TS2346: Supplied parameters do not match any signature of call target.
@@ -22,7 +23,7 @@ tests/cases/compiler/optionalParamArgsTest.ts(117,1): error TS2346: Supplied par
 tests/cases/compiler/optionalParamArgsTest.ts(118,1): error TS2346: Supplied parameters do not match any signature of call target.
 
 
-==== tests/cases/compiler/optionalParamArgsTest.ts (22 errors) ====
+==== tests/cases/compiler/optionalParamArgsTest.ts (23 errors) ====
     // Optional parameter and default argument tests
     
     // Key:
@@ -54,13 +55,15 @@ tests/cases/compiler/optionalParamArgsTest.ts(118,1): error TS2346: Supplied par
         public C1M4(C1M4A1:number,C1M4A2?:number) { return C1M4A1 + C1M4A2; }
     
         public C1M5(C1M5A1:number,C1M5A2:number=0,C1M5A3?:number) { return C1M5A1 + C1M5A2; }
+               ~~~~
+!!! error TS2393: Duplicate function implementation.
     
         // Negative test
         // "Optional parameters may only be followed by other optional parameters"
         public C1M5(C1M5A1:number,C1M5A2:number=0,C1M5A3:number) { return C1M5A1 + C1M5A2; }
                                                   ~~~~~~
 !!! error TS1016: A required parameter cannot follow an optional parameter.
-        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+               ~~~~
 !!! error TS2393: Duplicate function implementation.
     }
     
diff --git a/tests/baselines/reference/optionalPropertiesSyntax.errors.txt b/tests/baselines/reference/optionalPropertiesSyntax.errors.txt
index 1d081bb64a9..66c1cae2a7e 100644
--- a/tests/baselines/reference/optionalPropertiesSyntax.errors.txt
+++ b/tests/baselines/reference/optionalPropertiesSyntax.errors.txt
@@ -8,13 +8,14 @@ tests/cases/compiler/optionalPropertiesSyntax.ts(32,19): error TS1131: Property
 tests/cases/compiler/optionalPropertiesSyntax.ts(33,5): error TS1131: Property or signature expected.
 tests/cases/compiler/optionalPropertiesSyntax.ts(34,6): error TS1019: An index signature parameter cannot have a question mark.
 tests/cases/compiler/optionalPropertiesSyntax.ts(4,5): error TS2386: Overload signatures must all be optional or required.
+tests/cases/compiler/optionalPropertiesSyntax.ts(24,5): error TS2300: Duplicate identifier 'prop'.
 tests/cases/compiler/optionalPropertiesSyntax.ts(25,5): error TS2300: Duplicate identifier 'prop'.
 tests/cases/compiler/optionalPropertiesSyntax.ts(32,5): error TS2375: Duplicate number index signature.
 tests/cases/compiler/optionalPropertiesSyntax.ts(33,7): error TS2375: Duplicate number index signature.
 tests/cases/compiler/optionalPropertiesSyntax.ts(34,5): error TS2375: Duplicate number index signature.
 
 
-==== tests/cases/compiler/optionalPropertiesSyntax.ts (14 errors) ====
+==== tests/cases/compiler/optionalPropertiesSyntax.ts (15 errors) ====
     interface fnSigs {
         //functions signatures can be optional
         fn(): void;
@@ -51,6 +52,8 @@ tests/cases/compiler/optionalPropertiesSyntax.ts(34,5): error TS2375: Duplicate
     interface propertySig {
         //Property signatures can be optional
         prop: any;
+        ~~~~
+!!! error TS2300: Duplicate identifier 'prop'.
         prop?: any;
         ~~~~
 !!! error TS2300: Duplicate identifier 'prop'.
diff --git a/tests/baselines/reference/overloadsWithinClasses.errors.txt b/tests/baselines/reference/overloadsWithinClasses.errors.txt
index 1055290316c..02872861a4b 100644
--- a/tests/baselines/reference/overloadsWithinClasses.errors.txt
+++ b/tests/baselines/reference/overloadsWithinClasses.errors.txt
@@ -1,13 +1,16 @@
-tests/cases/compiler/overloadsWithinClasses.ts(5,5): error TS2393: Duplicate function implementation.
+tests/cases/compiler/overloadsWithinClasses.ts(3,12): error TS2393: Duplicate function implementation.
+tests/cases/compiler/overloadsWithinClasses.ts(5,12): error TS2393: Duplicate function implementation.
 
 
-==== tests/cases/compiler/overloadsWithinClasses.ts (1 errors) ====
+==== tests/cases/compiler/overloadsWithinClasses.ts (2 errors) ====
     class foo {
      
         static fnOverload( ) {}
+               ~~~~~~~~~~
+!!! error TS2393: Duplicate function implementation.
      
         static fnOverload(foo: string){ } // error
-        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+               ~~~~~~~~~~
 !!! error TS2393: Duplicate function implementation.
      
     }
diff --git a/tests/baselines/reference/parameterPropertyInConstructor2.errors.txt b/tests/baselines/reference/parameterPropertyInConstructor2.errors.txt
index d1a0513c1f6..5885385a20c 100644
--- a/tests/baselines/reference/parameterPropertyInConstructor2.errors.txt
+++ b/tests/baselines/reference/parameterPropertyInConstructor2.errors.txt
@@ -1,9 +1,10 @@
 tests/cases/compiler/parameterPropertyInConstructor2.ts(3,5): error TS2394: Overload signature is not compatible with function implementation.
 tests/cases/compiler/parameterPropertyInConstructor2.ts(3,17): error TS2369: A parameter property is only allowed in a constructor implementation.
+tests/cases/compiler/parameterPropertyInConstructor2.ts(3,24): error TS2300: Duplicate identifier 'names'.
 tests/cases/compiler/parameterPropertyInConstructor2.ts(4,24): error TS2300: Duplicate identifier 'names'.
 
 
-==== tests/cases/compiler/parameterPropertyInConstructor2.ts (3 errors) ====
+==== tests/cases/compiler/parameterPropertyInConstructor2.ts (4 errors) ====
     module mod {
       class Customers {
         constructor(public names: string);
@@ -11,6 +12,8 @@ tests/cases/compiler/parameterPropertyInConstructor2.ts(4,24): error TS2300: Dup
 !!! error TS2394: Overload signature is not compatible with function implementation.
                     ~~~~~~~~~~~~~~~~~~~~
 !!! error TS2369: A parameter property is only allowed in a constructor implementation.
+                           ~~~~~
+!!! error TS2300: Duplicate identifier 'names'.
         constructor(public names: string, public ages: number) {
                            ~~~~~
 !!! error TS2300: Duplicate identifier 'names'.
diff --git a/tests/baselines/reference/parser0_004152.errors.txt b/tests/baselines/reference/parser0_004152.errors.txt
index e1b19738922..cfd6161a48e 100644
--- a/tests/baselines/reference/parser0_004152.errors.txt
+++ b/tests/baselines/reference/parser0_004152.errors.txt
@@ -19,10 +19,12 @@ tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,94): error T
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,97): error TS1005: ';' expected.
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,98): error TS1068: Unexpected token. A constructor, method, accessor, or property was expected.
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,28): error TS2304: Cannot find name 'DisplayPosition'.
+tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,48): error TS2300: Duplicate identifier '3'.
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,51): error TS2300: Duplicate identifier '3'.
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,54): error TS2300: Duplicate identifier '3'.
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,57): error TS2300: Duplicate identifier '3'.
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,60): error TS2300: Duplicate identifier '3'.
+tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,63): error TS2300: Duplicate identifier '0'.
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,66): error TS2300: Duplicate identifier '3'.
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,69): error TS2300: Duplicate identifier '3'.
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,72): error TS2300: Duplicate identifier '3'.
@@ -34,7 +36,7 @@ tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(2,96): error T
 tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(3,25): error TS2304: Cannot find name 'SeedCoords'.
 
 
-==== tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts (34 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts (36 errors) ====
     export class Game {
                  ~~~~
 !!! error TS1148: Cannot compile external modules unless the '--module' flag is provided.
@@ -79,6 +81,8 @@ tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(3,25): error T
 !!! error TS1068: Unexpected token. A constructor, method, accessor, or property was expected.
                                ~~~~~~~~~~~~~~~
 !!! error TS2304: Cannot find name 'DisplayPosition'.
+                                                   ~
+!!! error TS2300: Duplicate identifier '3'.
                                                       ~
 !!! error TS2300: Duplicate identifier '3'.
                                                          ~
@@ -87,6 +91,8 @@ tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts(3,25): error T
 !!! error TS2300: Duplicate identifier '3'.
                                                                ~
 !!! error TS2300: Duplicate identifier '3'.
+                                                                  ~
+!!! error TS2300: Duplicate identifier '0'.
                                                                      ~
 !!! error TS2300: Duplicate identifier '3'.
                                                                         ~
diff --git a/tests/baselines/reference/parserErrorRecovery_ModuleElement2.errors.txt b/tests/baselines/reference/parserErrorRecovery_ModuleElement2.errors.txt
index 23f8d8bc166..eb4d6dc3471 100644
--- a/tests/baselines/reference/parserErrorRecovery_ModuleElement2.errors.txt
+++ b/tests/baselines/reference/parserErrorRecovery_ModuleElement2.errors.txt
@@ -1,17 +1,19 @@
 tests/cases/conformance/parser/ecmascript5/ErrorRecovery/ModuleElements/parserErrorRecovery_ModuleElement2.ts(7,1): error TS1128: Declaration or statement expected.
 tests/cases/conformance/parser/ecmascript5/ErrorRecovery/ModuleElements/parserErrorRecovery_ModuleElement2.ts(8,1): error TS1128: Declaration or statement expected.
-tests/cases/conformance/parser/ecmascript5/ErrorRecovery/ModuleElements/parserErrorRecovery_ModuleElement2.ts(4,1): error TS2393: Duplicate function implementation.
+tests/cases/conformance/parser/ecmascript5/ErrorRecovery/ModuleElements/parserErrorRecovery_ModuleElement2.ts(1,10): error TS2393: Duplicate function implementation.
+tests/cases/conformance/parser/ecmascript5/ErrorRecovery/ModuleElements/parserErrorRecovery_ModuleElement2.ts(4,10): error TS2393: Duplicate function implementation.
 
 
-==== tests/cases/conformance/parser/ecmascript5/ErrorRecovery/ModuleElements/parserErrorRecovery_ModuleElement2.ts (3 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/ErrorRecovery/ModuleElements/parserErrorRecovery_ModuleElement2.ts (4 errors) ====
     function foo() {
+             ~~~
+!!! error TS2393: Duplicate function implementation.
     }
     
     function foo() {
-    ~~~~~~~~~~~~~~~~
-    }
-    ~
+             ~~~
 !!! error TS2393: Duplicate function implementation.
+    }
     
     )
     ~
diff --git a/tests/baselines/reference/parserMemberFunctionDeclarationAmbiguities1.errors.txt b/tests/baselines/reference/parserMemberFunctionDeclarationAmbiguities1.errors.txt
index 1c239f59b22..e0d49bb8470 100644
--- a/tests/baselines/reference/parserMemberFunctionDeclarationAmbiguities1.errors.txt
+++ b/tests/baselines/reference/parserMemberFunctionDeclarationAmbiguities1.errors.txt
@@ -1,28 +1,40 @@
-tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(5,3): error TS2393: Duplicate function implementation.
-tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(6,3): error TS2393: Duplicate function implementation.
-tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(11,3): error TS2393: Duplicate function implementation.
-tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(12,3): error TS2393: Duplicate function implementation.
+tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(2,3): error TS2393: Duplicate function implementation.
+tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(3,3): error TS2393: Duplicate function implementation.
+tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(5,10): error TS2393: Duplicate function implementation.
+tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(6,10): error TS2393: Duplicate function implementation.
+tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(8,17): error TS2393: Duplicate function implementation.
+tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(9,17): error TS2393: Duplicate function implementation.
+tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(11,10): error TS2393: Duplicate function implementation.
+tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts(12,10): error TS2393: Duplicate function implementation.
 
 
-==== tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts (4 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclarationAmbiguities1.ts (8 errors) ====
     class C {
       public() {}
+      ~~~~~~
+!!! error TS2393: Duplicate function implementation.
       static() {}
+      ~~~~~~
+!!! error TS2393: Duplicate function implementation.
     
       public public() {}
-      ~~~~~~~~~~~~~~~~~~
+             ~~~~~~
 !!! error TS2393: Duplicate function implementation.
       public static() {}
-      ~~~~~~~~~~~~~~~~~~
+             ~~~~~~
 !!! error TS2393: Duplicate function implementation.
     
       public static public() {}
+                    ~~~~~~
+!!! error TS2393: Duplicate function implementation.
       public static static() {}
+                    ~~~~~~
+!!! error TS2393: Duplicate function implementation.
       
       static public() {}
-      ~~~~~~~~~~~~~~~~~~
+             ~~~~~~
 !!! error TS2393: Duplicate function implementation.
       static static() {}
-      ~~~~~~~~~~~~~~~~~~
+             ~~~~~~
 !!! error TS2393: Duplicate function implementation.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/propertyAndAccessorWithSameName.errors.txt b/tests/baselines/reference/propertyAndAccessorWithSameName.errors.txt
index ece553abea8..9ef943cc07a 100644
--- a/tests/baselines/reference/propertyAndAccessorWithSameName.errors.txt
+++ b/tests/baselines/reference/propertyAndAccessorWithSameName.errors.txt
@@ -2,15 +2,20 @@ tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWi
 tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts(10,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts(15,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts(18,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts(2,5): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts(3,9): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts(9,5): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts(10,9): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts(14,13): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts(15,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts(18,9): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts (8 errors) ====
+==== tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWithSameName.ts (11 errors) ====
     class C {
         x: number;
+        ~
+!!! error TS2300: Duplicate identifier 'x'.
         get x() { // error
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -22,6 +27,8 @@ tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWi
     
     class D {
         x: number;
+        ~
+!!! error TS2300: Duplicate identifier 'x'.
         set x(v) { } // error
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -31,6 +38,8 @@ tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndAccessorWi
     
     class E {
         private x: number;
+                ~
+!!! error TS2300: Duplicate identifier 'x'.
         get x() { // error
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
diff --git a/tests/baselines/reference/propertyAndFunctionWithSameName.errors.txt b/tests/baselines/reference/propertyAndFunctionWithSameName.errors.txt
index a98382863a4..84428a2dfb1 100644
--- a/tests/baselines/reference/propertyAndFunctionWithSameName.errors.txt
+++ b/tests/baselines/reference/propertyAndFunctionWithSameName.errors.txt
@@ -1,10 +1,14 @@
+tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndFunctionWithSameName.ts(2,5): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndFunctionWithSameName.ts(3,5): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndFunctionWithSameName.ts(9,5): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndFunctionWithSameName.ts(10,5): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndFunctionWithSameName.ts (2 errors) ====
+==== tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndFunctionWithSameName.ts (4 errors) ====
     class C {
         x: number;
+        ~
+!!! error TS2300: Duplicate identifier 'x'.
         x() { // error
         ~
 !!! error TS2300: Duplicate identifier 'x'.
@@ -14,6 +18,8 @@ tests/cases/conformance/classes/propertyMemberDeclarations/propertyAndFunctionWi
     
     class D {
         x: number;
+        ~
+!!! error TS2300: Duplicate identifier 'x'.
         x(v) { } // error
         ~
 !!! error TS2300: Duplicate identifier 'x'.
diff --git a/tests/baselines/reference/propertySignatures.errors.txt b/tests/baselines/reference/propertySignatures.errors.txt
index d5ab5678c00..fd415334e74 100644
--- a/tests/baselines/reference/propertySignatures.errors.txt
+++ b/tests/baselines/reference/propertySignatures.errors.txt
@@ -1,10 +1,13 @@
+tests/cases/compiler/propertySignatures.ts(2,13): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/propertySignatures.ts(2,23): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/propertySignatures.ts(14,12): error TS2304: Cannot find name 'foo'.
 
 
-==== tests/cases/compiler/propertySignatures.ts (2 errors) ====
+==== tests/cases/compiler/propertySignatures.ts (3 errors) ====
     // Should be error - duplicate identifiers
     var foo1: { a:string; a: string; };
+                ~
+!!! error TS2300: Duplicate identifier 'a'.
                           ~
 !!! error TS2300: Duplicate identifier 'a'.
     
diff --git a/tests/baselines/reference/reassignStaticProp.errors.txt b/tests/baselines/reference/reassignStaticProp.errors.txt
index eb373437609..bbcfe826787 100644
--- a/tests/baselines/reference/reassignStaticProp.errors.txt
+++ b/tests/baselines/reference/reassignStaticProp.errors.txt
@@ -1,10 +1,13 @@
+tests/cases/compiler/reassignStaticProp.ts(3,12): error TS2300: Duplicate identifier 'bar'.
 tests/cases/compiler/reassignStaticProp.ts(5,12): error TS2300: Duplicate identifier 'bar'.
 
 
-==== tests/cases/compiler/reassignStaticProp.ts (1 errors) ====
+==== tests/cases/compiler/reassignStaticProp.ts (2 errors) ====
     class foo {
      
         static bar = 1;
+               ~~~
+!!! error TS2300: Duplicate identifier 'bar'.
      
         static bar:string; // errror - duplicate id
                ~~~
diff --git a/tests/baselines/reference/sourceMapValidationEnums.errors.txt b/tests/baselines/reference/sourceMapValidationEnums.errors.txt
index 4ecb81edeea..ae42f0b00b2 100644
--- a/tests/baselines/reference/sourceMapValidationEnums.errors.txt
+++ b/tests/baselines/reference/sourceMapValidationEnums.errors.txt
@@ -1,9 +1,12 @@
+tests/cases/compiler/sourceMapValidationEnums.ts(2,5): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/sourceMapValidationEnums.ts(4,5): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/compiler/sourceMapValidationEnums.ts (1 errors) ====
+==== tests/cases/compiler/sourceMapValidationEnums.ts (2 errors) ====
     enum e {
         x,
+        ~
+!!! error TS2300: Duplicate identifier 'x'.
         y,
         x
         ~
diff --git a/tests/baselines/reference/staticClassMemberError.errors.txt b/tests/baselines/reference/staticClassMemberError.errors.txt
index e0768b03967..9483e3387b7 100644
--- a/tests/baselines/reference/staticClassMemberError.errors.txt
+++ b/tests/baselines/reference/staticClassMemberError.errors.txt
@@ -1,9 +1,10 @@
 tests/cases/compiler/staticClassMemberError.ts(4,3): error TS2304: Cannot find name 's'.
+tests/cases/compiler/staticClassMemberError.ts(9,10): error TS2300: Duplicate identifier 'Foo'.
 tests/cases/compiler/staticClassMemberError.ts(9,10): error TS2391: Function implementation is missing or not immediately following the declaration.
 tests/cases/compiler/staticClassMemberError.ts(10,7): error TS2300: Duplicate identifier 'Foo'.
 
 
-==== tests/cases/compiler/staticClassMemberError.ts (3 errors) ====
+==== tests/cases/compiler/staticClassMemberError.ts (4 errors) ====
     class C {
     	static s;
     	public a() {
@@ -16,6 +17,8 @@ tests/cases/compiler/staticClassMemberError.ts(10,7): error TS2300: Duplicate id
     // just want to make sure this one doesn't crash the compiler
     function Foo();
              ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
+             ~~~
 !!! error TS2391: Function implementation is missing or not immediately following the declaration.
     class Foo {
           ~~~
diff --git a/tests/baselines/reference/stringLiteralTypesInImplementationSignatures2.errors.txt b/tests/baselines/reference/stringLiteralTypesInImplementationSignatures2.errors.txt
index ed30960896e..cbc517e0520 100644
--- a/tests/baselines/reference/stringLiteralTypesInImplementationSignatures2.errors.txt
+++ b/tests/baselines/reference/stringLiteralTypesInImplementationSignatures2.errors.txt
@@ -8,11 +8,12 @@ tests/cases/conformance/types/objectTypeLiteral/callSignatures/stringLiteralType
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/stringLiteralTypesInImplementationSignatures2.ts(20,5): error TS2382: Specialized overload signature is not assignable to any non-specialized signature.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/stringLiteralTypesInImplementationSignatures2.ts(21,5): error TS2382: Specialized overload signature is not assignable to any non-specialized signature.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/stringLiteralTypesInImplementationSignatures2.ts(22,5): error TS2382: Specialized overload signature is not assignable to any non-specialized signature.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/stringLiteralTypesInImplementationSignatures2.ts(26,5): error TS2300: Duplicate identifier 'foo'.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/stringLiteralTypesInImplementationSignatures2.ts(26,5): error TS2381: A signature with an implementation cannot use a string literal type.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/stringLiteralTypesInImplementationSignatures2.ts(27,5): error TS2300: Duplicate identifier 'foo'.
 
 
-==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/stringLiteralTypesInImplementationSignatures2.ts (12 errors) ====
+==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/stringLiteralTypesInImplementationSignatures2.ts (13 errors) ====
     // String literal types are only valid in overload signatures
     
     function foo(x: any);
@@ -59,6 +60,8 @@ tests/cases/conformance/types/objectTypeLiteral/callSignatures/stringLiteralType
     
     var b = {
         foo(x: 'hi') { },
+        ~~~
+!!! error TS2300: Duplicate identifier 'foo'.
         ~~~~~~~~~~~~~~~~
 !!! error TS2381: A signature with an implementation cannot use a string literal type.
         foo(x: 'a') { },
diff --git a/tests/baselines/reference/stringNamedPropertyDuplicates.errors.txt b/tests/baselines/reference/stringNamedPropertyDuplicates.errors.txt
index 8e8af394d39..e15cb03e062 100644
--- a/tests/baselines/reference/stringNamedPropertyDuplicates.errors.txt
+++ b/tests/baselines/reference/stringNamedPropertyDuplicates.errors.txt
@@ -1,18 +1,27 @@
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(20,5): error TS1005: ',' expected.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(2,5): error TS2300: Duplicate identifier '"a b"'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(3,5): error TS2300: Duplicate identifier '"a b"'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(4,12): error TS2300: Duplicate identifier '"c d"'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(5,12): error TS2300: Duplicate identifier '"c d"'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(9,5): error TS2300: Duplicate identifier '"a b"'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(10,5): error TS2300: Duplicate identifier '"a b"'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(14,5): error TS2300: Duplicate identifier '"a b"'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(15,5): error TS2300: Duplicate identifier '"a b"'.
+tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(19,5): error TS2300: Duplicate identifier '"a b"'.
 tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts(20,5): error TS2300: Duplicate identifier '"a b"'.
 
 
-==== tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts (6 errors) ====
+==== tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPropertyDuplicates.ts (11 errors) ====
     class C {
         "a b": number;
+        ~~~~~
+!!! error TS2300: Duplicate identifier '"a b"'.
         "a b": number;
         ~~~~~
 !!! error TS2300: Duplicate identifier '"a b"'.
         static "c d": number;
+               ~~~~~
+!!! error TS2300: Duplicate identifier '"c d"'.
         static "c d": number;
                ~~~~~
 !!! error TS2300: Duplicate identifier '"c d"'.
@@ -20,6 +29,8 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPr
     
     interface I {
         "a b": number;
+        ~~~~~
+!!! error TS2300: Duplicate identifier '"a b"'.
         "a b": number;
         ~~~~~
 !!! error TS2300: Duplicate identifier '"a b"'.
@@ -27,6 +38,8 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPr
     
     var a: {
         "a b": number;
+        ~~~~~
+!!! error TS2300: Duplicate identifier '"a b"'.
         "a b": number;
         ~~~~~
 !!! error TS2300: Duplicate identifier '"a b"'.
@@ -34,6 +47,8 @@ tests/cases/conformance/types/objectTypeLiteral/propertySignatures/stringNamedPr
     
     var b = {
         "a b": 1
+        ~~~~~
+!!! error TS2300: Duplicate identifier '"a b"'.
         "a b": 1
         ~~~~~
 !!! error TS1005: ',' expected.
diff --git a/tests/baselines/reference/targetTypeCastTest.errors.txt b/tests/baselines/reference/targetTypeCastTest.errors.txt
index b719ac656fe..c44de5535d0 100644
--- a/tests/baselines/reference/targetTypeCastTest.errors.txt
+++ b/tests/baselines/reference/targetTypeCastTest.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/targetTypeCastTest.ts(1,13): error TS2300: Duplicate identifier 'Point'.
 tests/cases/compiler/targetTypeCastTest.ts(3,10): error TS2300: Duplicate identifier 'Point'.
 
 
-==== tests/cases/compiler/targetTypeCastTest.ts (1 errors) ====
+==== tests/cases/compiler/targetTypeCastTest.ts (2 errors) ====
     declare var Point: { new(x:number, y:number): {x: number; y: number; }; }
+                ~~~~~
+!!! error TS2300: Duplicate identifier 'Point'.
     
     function Point(x, y) {
              ~~~~~
diff --git a/tests/baselines/reference/targetTypeTest1.errors.txt b/tests/baselines/reference/targetTypeTest1.errors.txt
index dccc680abaa..a0b05690a3b 100644
--- a/tests/baselines/reference/targetTypeTest1.errors.txt
+++ b/tests/baselines/reference/targetTypeTest1.errors.txt
@@ -1,10 +1,14 @@
+tests/cases/compiler/targetTypeTest1.ts(1,15): error TS2300: Duplicate identifier 'Point'.
 tests/cases/compiler/targetTypeTest1.ts(14,10): error TS2300: Duplicate identifier 'Point'.
 tests/cases/compiler/targetTypeTest1.ts(19,18): error TS2384: Overload signatures must all be ambient or non-ambient.
+tests/cases/compiler/targetTypeTest1.ts(53,15): error TS2300: Duplicate identifier 'C'.
 tests/cases/compiler/targetTypeTest1.ts(60,10): error TS2300: Duplicate identifier 'C'.
 
 
-==== tests/cases/compiler/targetTypeTest1.ts (3 errors) ====
+==== tests/cases/compiler/targetTypeTest1.ts (5 errors) ====
     declare class Point
+                  ~~~~~
+!!! error TS2300: Duplicate identifier 'Point'.
     {
           constructor(x: number, y: number);
           public x: number;
@@ -61,6 +65,8 @@ tests/cases/compiler/targetTypeTest1.ts(60,10): error TS2300: Duplicate identifi
     }
     
     declare class C {
+                  ~
+!!! error TS2300: Duplicate identifier 'C'.
         constructor(a:number, b:number);
     	public a : number;
     	public b: number;    
diff --git a/tests/baselines/reference/twoAccessorsWithSameName.errors.txt b/tests/baselines/reference/twoAccessorsWithSameName.errors.txt
index 6b4990ceeda..81da707c566 100644
--- a/tests/baselines/reference/twoAccessorsWithSameName.errors.txt
+++ b/tests/baselines/reference/twoAccessorsWithSameName.errors.txt
@@ -9,16 +9,21 @@ tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameN
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts(24,9): error TS1118: An object literal cannot have multiple get/set accessors with the same name.
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts(30,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts(33,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts(2,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts(3,9): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts(7,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts(8,9): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts(19,9): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts(24,9): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts (14 errors) ====
+==== tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName.ts (17 errors) ====
     class C {
         get x() { return 1; }
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
         get x() { return 1; } // error
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -30,6 +35,8 @@ tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameN
         set x(v) {  }
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
         set x(v) {  } // error
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -52,6 +59,8 @@ tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameN
         get x() {
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+            ~
+!!! error TS2300: Duplicate identifier 'x'.
             return 1;
         },
     
diff --git a/tests/baselines/reference/twoAccessorsWithSameName2.errors.txt b/tests/baselines/reference/twoAccessorsWithSameName2.errors.txt
index 2a6db805b19..836a06a8192 100644
--- a/tests/baselines/reference/twoAccessorsWithSameName2.errors.txt
+++ b/tests/baselines/reference/twoAccessorsWithSameName2.errors.txt
@@ -4,15 +4,19 @@ tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameN
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName2.ts(8,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName2.ts(12,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName2.ts(15,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName2.ts(2,16): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName2.ts(3,16): error TS2300: Duplicate identifier 'x'.
+tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName2.ts(7,16): error TS2300: Duplicate identifier 'x'.
 tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName2.ts(8,16): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName2.ts (8 errors) ====
+==== tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameName2.ts (10 errors) ====
     class C {
         static get x() { return 1; }
                    ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+                   ~
+!!! error TS2300: Duplicate identifier 'x'.
         static get x() { return 1; } // error
                    ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -24,6 +28,8 @@ tests/cases/conformance/classes/propertyMemberDeclarations/twoAccessorsWithSameN
         static set x(v) {  }
                    ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
+                   ~
+!!! error TS2300: Duplicate identifier 'x'.
         static set x(v) {  } // error
                    ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
diff --git a/tests/baselines/reference/varAndFunctionShareName.errors.txt b/tests/baselines/reference/varAndFunctionShareName.errors.txt
index aa518152fcc..dc4dd4e1b3b 100644
--- a/tests/baselines/reference/varAndFunctionShareName.errors.txt
+++ b/tests/baselines/reference/varAndFunctionShareName.errors.txt
@@ -1,8 +1,11 @@
+tests/cases/compiler/varAndFunctionShareName.ts(1,5): error TS2300: Duplicate identifier 'myFn'.
 tests/cases/compiler/varAndFunctionShareName.ts(2,10): error TS2300: Duplicate identifier 'myFn'.
 
 
-==== tests/cases/compiler/varAndFunctionShareName.ts (1 errors) ====
+==== tests/cases/compiler/varAndFunctionShareName.ts (2 errors) ====
     var myFn;
+        ~~~~
+!!! error TS2300: Duplicate identifier 'myFn'.
     function myFn(): any { }
              ~~~~
 !!! error TS2300: Duplicate identifier 'myFn'.
\ No newline at end of file
diff --git a/tests/cases/compiler/augmentedTypesClass2.ts b/tests/cases/compiler/augmentedTypesClass2.ts
index a744e2e62e1..c6d64e2bf82 100644
--- a/tests/cases/compiler/augmentedTypesClass2.ts
+++ b/tests/cases/compiler/augmentedTypesClass2.ts
@@ -1,7 +1,7 @@
 // Checking class with other things in type space not value space
 
 // class then interface
-class c11 {
+class c11 { // error
     foo() {
         return 1;
     }
diff --git a/tests/cases/compiler/augmentedTypesClass2a.ts b/tests/cases/compiler/augmentedTypesClass2a.ts
index ebb1bf6b1b5..c8098a7f133 100644
--- a/tests/cases/compiler/augmentedTypesClass2a.ts
+++ b/tests/cases/compiler/augmentedTypesClass2a.ts
@@ -1,4 +1,4 @@
 //// class then function
-class c2 { public foo() { } }
+class c2 { public foo() { } } // error
 function c2() { } // error
 var c2 = () => { }
\ No newline at end of file
diff --git a/tests/cases/compiler/augmentedTypesClass4.ts b/tests/cases/compiler/augmentedTypesClass4.ts
index 54d96b617e5..d8ab0708272 100644
--- a/tests/cases/compiler/augmentedTypesClass4.ts
+++ b/tests/cases/compiler/augmentedTypesClass4.ts
@@ -1,3 +1,3 @@
 //// class then class
-class c3 { public foo() { } }
+class c3 { public foo() { } } // error
 class c3 { public bar() { } } // error
diff --git a/tests/cases/compiler/augmentedTypesEnum.ts b/tests/cases/compiler/augmentedTypesEnum.ts
index 96ec07fef39..2efcde826ce 100644
--- a/tests/cases/compiler/augmentedTypesEnum.ts
+++ b/tests/cases/compiler/augmentedTypesEnum.ts
@@ -1,23 +1,23 @@
 // enum then var
-enum e1111 { One }
+enum e1111 { One } // error
 var e1111 = 1; // error
 
 // enum then function
-enum e2 { One }
+enum e2 { One } // error
 function e2() { } // error
 
-enum e3 { One }
+enum e3 { One } // error
 var e3 = () => { } // error
 
 // enum then class
-enum e4 { One }
+enum e4 { One } // error
 class e4 { public foo() { } } // error
 
 // enum then enum
 enum e5 { One }
-enum e5 { Two }
+enum e5 { Two } // error
 
-enum e5a { One }
+enum e5a { One } // error
 enum e5a { One } // error
 
 // enum then internal module
diff --git a/tests/cases/compiler/augmentedTypesEnum2.ts b/tests/cases/compiler/augmentedTypesEnum2.ts
index 8801c5d935b..2ad69c12f02 100644
--- a/tests/cases/compiler/augmentedTypesEnum2.ts
+++ b/tests/cases/compiler/augmentedTypesEnum2.ts
@@ -1,14 +1,14 @@
 // enum then interface
-enum e1 { One }
+enum e1 { One } // error
 
-interface e1 {
+interface e1 { // error
     foo(): void;
 }
 
 // interface then enum works
 
 // enum then class
-enum e2 { One };
+enum e2 { One }; // error
 class e2 { // error
     foo() {
         return 1;
diff --git a/tests/cases/compiler/augmentedTypesFunction.ts b/tests/cases/compiler/augmentedTypesFunction.ts
index 14bb1f718e8..ab6627f9463 100644
--- a/tests/cases/compiler/augmentedTypesFunction.ts
+++ b/tests/cases/compiler/augmentedTypesFunction.ts
@@ -1,23 +1,23 @@
 // function then var
-function y1() { }
+function y1() { } // error
 var y1 = 1; // error
 
 // function then function
-function y2() { }
+function y2() { } // error
 function y2() { } // error
 
-function y2a() { }
+function y2a() { }  // error
 var y2a = () => { } // error
 
 // function then class
-function y3() { }
+function y3() { } // error
 class y3 { } // error
 
-function y3a() { }
+function y3a() { } // error
 class y3a { public foo() { } } // error
 
 // function then enum
-function y4() { }
+function y4() { } // error
 enum y4 { One } // error
 
 // function then internal module
diff --git a/tests/cases/compiler/augmentedTypesInterface.ts b/tests/cases/compiler/augmentedTypesInterface.ts
index b9f84d4d8b2..72c85d6619d 100644
--- a/tests/cases/compiler/augmentedTypesInterface.ts
+++ b/tests/cases/compiler/augmentedTypesInterface.ts
@@ -9,7 +9,7 @@ interface i {
 }
 
 // interface then class
-interface i2 {
+interface i2 { // error
     foo(): void;
 }
 
@@ -20,7 +20,7 @@ class i2 {  // error
 }
 
 // interface then enum
-interface i3 {
+interface i3 { // error
     foo(): void;
 }
 enum i3 { One }; // error
diff --git a/tests/cases/compiler/augmentedTypesModules.ts b/tests/cases/compiler/augmentedTypesModules.ts
index 6857abf1718..84f03549a42 100644
--- a/tests/cases/compiler/augmentedTypesModules.ts
+++ b/tests/cases/compiler/augmentedTypesModules.ts
@@ -2,18 +2,18 @@
 module m1 { }
 var m1 = 1; // Should be allowed
 
-module m1a { var y = 2; }
-var m1a = 1;
+module m1a { var y = 2; } // error
+var m1a = 1; // error
 
-module m1b { export var y = 2; }
-var m1b = 1;
+module m1b { export var y = 2; } // error
+var m1b = 1; // error
 
 module m1c {
     export interface I { foo(): void; }
 }
 var m1c = 1; // Should be allowed
 
-module m1d {
+module m1d { // error
     export class I { foo() { } }
 }
 var m1d = 1; // error
diff --git a/tests/cases/compiler/augmentedTypesVar.ts b/tests/cases/compiler/augmentedTypesVar.ts
index 75cab810c13..c7e40c8b0e7 100644
--- a/tests/cases/compiler/augmentedTypesVar.ts
+++ b/tests/cases/compiler/augmentedTypesVar.ts
@@ -3,17 +3,17 @@ var x1 = 1;
 var x1 = 2;
 
 // var then function
-var x2 = 1;
-function x2() { } // should be an error
+var x2 = 1; // error
+function x2() { } // error
 
-var x3 = 1;
-var x3 = () => { } // should be an error
+var x3 = 1; 
+var x3 = () => { } // error
 
 // var then class
-var x4 = 1;
+var x4 = 1; // error
 class x4 { } // error
 
-var x4a = 1;
+var x4a = 1; // error
 class x4a { public foo() { } } // error
 
 // var then enum
@@ -24,10 +24,10 @@ enum x5 { One } // error
 var x6 = 1;
 module x6 { } // ok since non-instantiated
 
-var x6a = 1;
+var x6a = 1; // error
 module x6a { var y = 2; } // error since instantiated
 
-var x6b = 1;
+var x6b = 1; // error
 module x6b { export var y = 2; } // error
 
 // var then import, messes with other error reporting
diff --git a/tests/cases/compiler/callOnInstance.ts b/tests/cases/compiler/callOnInstance.ts
index 0125121c12a..0b38dcd12cd 100644
--- a/tests/cases/compiler/callOnInstance.ts
+++ b/tests/cases/compiler/callOnInstance.ts
@@ -1,6 +1,6 @@
-declare function D(): string;
+declare function D(): string; // error
 
-declare class D { constructor (value: number); } // Duplicate identifier
+declare class D { constructor (value: number); } // error
 
 var s1: string = D(); // OK
 
diff --git a/tests/cases/compiler/callOverloads1.ts b/tests/cases/compiler/callOverloads1.ts
index 17abfb7890a..e2ce278eec0 100644
--- a/tests/cases/compiler/callOverloads1.ts
+++ b/tests/cases/compiler/callOverloads1.ts
@@ -1,4 +1,4 @@
-class Foo {    
+class Foo { // error
     bar1() { /*WScript.Echo("bar1");*/ }
 
     constructor(x: any) {
diff --git a/tests/cases/compiler/callOverloads2.ts b/tests/cases/compiler/callOverloads2.ts
index a5db65f505a..e18815fd46b 100644
--- a/tests/cases/compiler/callOverloads2.ts
+++ b/tests/cases/compiler/callOverloads2.ts
@@ -1,6 +1,6 @@
 
 
-class Foo {    
+class Foo { // error
     bar1() { /*WScript.Echo("bar1");*/ }
 
     constructor(x: any) {
@@ -8,10 +8,10 @@ class Foo {
     }
 }
 
-function Foo();
+function Foo(); // error
 
-function F1(s:string) {return s;}
-function F1(a:any) { return a;} // error -  duplicate identifier
+function F1(s:string) {return s;} // error
+function F1(a:any) { return a;} // error
 
 function Goo(s:string); // error - no implementation
 
diff --git a/tests/cases/compiler/callOverloads3.ts b/tests/cases/compiler/callOverloads3.ts
index 6b7e1bba907..be14dd478fa 100644
--- a/tests/cases/compiler/callOverloads3.ts
+++ b/tests/cases/compiler/callOverloads3.ts
@@ -1,7 +1,7 @@
 
-function Foo():Foo;
-function Foo(s:string):Foo;
-class Foo {    
+function Foo():Foo; // error
+function Foo(s:string):Foo; // error
+class Foo { // error
     bar1() { /*WScript.Echo("bar1");*/ }
     constructor(x: any) {
         // WScript.Echo("Constructor function has executed");
diff --git a/tests/cases/compiler/callOverloads4.ts b/tests/cases/compiler/callOverloads4.ts
index 58d89c53bdc..7240e73d0ac 100644
--- a/tests/cases/compiler/callOverloads4.ts
+++ b/tests/cases/compiler/callOverloads4.ts
@@ -1,7 +1,7 @@
 
-function Foo():Foo;
-function Foo(s:string):Foo;
-class Foo {    
+function Foo():Foo; // error
+function Foo(s:string):Foo; // error
+class Foo { // error
     bar1() { /*WScript.Echo("bar1");*/ }
     constructor(s: string);
     constructor(x: any) {
diff --git a/tests/cases/compiler/callOverloads5.ts b/tests/cases/compiler/callOverloads5.ts
index 9e491f7d257..212b68b168a 100644
--- a/tests/cases/compiler/callOverloads5.ts
+++ b/tests/cases/compiler/callOverloads5.ts
@@ -1,6 +1,6 @@
-function Foo():Foo;
-function Foo(s:string):Foo;
-class Foo {
+function Foo():Foo; // error
+function Foo(s:string):Foo; // error
+class Foo { // error
 	bar1(s:string);
 	bar1(n:number);
     bar1(a:any) { /*WScript.Echo(a);*/ }
diff --git a/tests/cases/compiler/class1.ts b/tests/cases/compiler/class1.ts
index d7c7ce2ae0a..c7b2115b88b 100644
--- a/tests/cases/compiler/class1.ts
+++ b/tests/cases/compiler/class1.ts
@@ -1,2 +1,2 @@
-interface foo{ }
-class foo{ }
\ No newline at end of file
+interface foo{ } // error
+class foo{ } // error
\ No newline at end of file
diff --git a/tests/cases/compiler/classAndInterface1.ts b/tests/cases/compiler/classAndInterface1.ts
index 06ada1c8a49..79b02915857 100644
--- a/tests/cases/compiler/classAndInterface1.ts
+++ b/tests/cases/compiler/classAndInterface1.ts
@@ -1,2 +1,2 @@
-class cli { }
+ class cli { } // error
 interface cli { } // error
\ No newline at end of file
diff --git a/tests/cases/conformance/classes/classDeclarations/classAndVariableWithSameName.ts b/tests/cases/conformance/classes/classDeclarations/classAndVariableWithSameName.ts
index 13bc603fada..cd42d742101 100644
--- a/tests/cases/conformance/classes/classDeclarations/classAndVariableWithSameName.ts
+++ b/tests/cases/conformance/classes/classDeclarations/classAndVariableWithSameName.ts
@@ -1,8 +1,8 @@
-class C { foo: string; }
+class C { foo: string; } // error
 var C = ''; // error
 
 module M {
-    class D {
+    class D { // error
         bar: string;
     }
 
diff --git a/tests/cases/conformance/classes/constructorDeclarations/classWithTwoConstructorDefinitions.ts b/tests/cases/conformance/classes/constructorDeclarations/classWithTwoConstructorDefinitions.ts
index 3744cb1f5f4..b3f535c4c3d 100644
--- a/tests/cases/conformance/classes/constructorDeclarations/classWithTwoConstructorDefinitions.ts
+++ b/tests/cases/conformance/classes/constructorDeclarations/classWithTwoConstructorDefinitions.ts
@@ -1,9 +1,9 @@
 class C {
-    constructor() { }
+    constructor() { } // error
     constructor(x) { } // error
 }
 
 class D<T> {
-    constructor(x: T) { }
+    constructor(x: T) { } // error
     constructor(x: T, y: T) { } // error
 }
\ No newline at end of file
diff --git a/tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts b/tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts
index 3164e0a4734..04f1acd84ca 100644
--- a/tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts
+++ b/tests/cases/conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts
@@ -17,8 +17,8 @@ c.foo();
 c.foo(1);
 
 var b = {
-    foo(x = 1),
-    foo(x = 1) { },
+    foo(x = 1), // error
+    foo(x = 1) { }, // error
 }
 
 b.foo();
diff --git a/tests/cases/fourslash/addFunctionInDuplicatedConstructorClassBody.ts b/tests/cases/fourslash/addFunctionInDuplicatedConstructorClassBody.ts
index 3315a226528..adbdd4820a0 100644
--- a/tests/cases/fourslash/addFunctionInDuplicatedConstructorClassBody.ts
+++ b/tests/cases/fourslash/addFunctionInDuplicatedConstructorClassBody.ts
@@ -9,4 +9,4 @@
 goTo.marker();
 var func = 'fn() { }';
 edit.insert(func);
-verify.numberOfErrorsInCurrentFile(1);
+verify.numberOfErrorsInCurrentFile(2);
diff --git a/tests/cases/fourslash/inheritedModuleMembersForClodule2.ts b/tests/cases/fourslash/inheritedModuleMembersForClodule2.ts
index 2be62b045c2..7380936d6b2 100644
--- a/tests/cases/fourslash/inheritedModuleMembersForClodule2.ts
+++ b/tests/cases/fourslash/inheritedModuleMembersForClodule2.ts
@@ -14,4 +14,4 @@
 
 goTo.marker();
 verify.quickInfoExists();
-verify.numberOfErrorsInCurrentFile(2);
\ No newline at end of file
+verify.numberOfErrorsInCurrentFile(4);
\ No newline at end of file
diff --git a/tests/cases/fourslash/insertReturnStatementInDuplicateIdentifierFunction.ts b/tests/cases/fourslash/insertReturnStatementInDuplicateIdentifierFunction.ts
index a5fd6623610..8abdac6d206 100644
--- a/tests/cases/fourslash/insertReturnStatementInDuplicateIdentifierFunction.ts
+++ b/tests/cases/fourslash/insertReturnStatementInDuplicateIdentifierFunction.ts
@@ -6,9 +6,9 @@
 goTo.marker();
 
 // One error: duplicate identifier 'foo'
-verify.numberOfErrorsInCurrentFile(1);
+verify.numberOfErrorsInCurrentFile(2);
 
 // Shouldn't change the number of errors
 edit.insert('return null;');
-verify.numberOfErrorsInCurrentFile(1);
+verify.numberOfErrorsInCurrentFile(2);