diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index d409d1ea2fa..85cde0c9551 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -8942,6 +8942,10 @@ module ts {
             if (!nodeCanBeDecorated(node)) {
                 return;
             }
+            
+            if (!compilerOptions.experimentalDecorators) {
+                error(node, Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Specify_experimentalDecorators_to_remove_this_warning);
+            }
 
             if (compilerOptions.emitDecoratorMetadata) {
                 // we only need to perform these checks if we are emitting serialized type metadata for the target of a decorator.
diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 64784590024..351f1caec94 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -188,10 +188,16 @@ module ts {
             type: "boolean",
             description: Diagnostics.Watch_input_files,
         },
+        {
+            name: "experimentalDecorators",
+            type: "boolean",
+            description: Diagnostics.Enables_experimental_support_for_ES7_decorators
+        },
         {
             name: "emitDecoratorMetadata",
             type: "boolean",
-            experimental: true
+            experimental: true,
+            description: Diagnostics.Enables_experimental_support_for_emitting_type_metadata_for_decorators
         }
     ];
 
diff --git a/src/compiler/diagnosticInformationMap.generated.ts b/src/compiler/diagnosticInformationMap.generated.ts
index 8dd6ea6dc55..a42ce1b2338 100644
--- a/src/compiler/diagnosticInformationMap.generated.ts
+++ b/src/compiler/diagnosticInformationMap.generated.ts
@@ -174,6 +174,7 @@ module ts {
         Type_expected_0_is_a_reserved_word_in_strict_mode: { code: 1215, category: DiagnosticCategory.Error, key: "Type expected. '{0}' is a reserved word in strict mode" },
         Type_expected_0_is_a_reserved_word_in_strict_mode_Class_definitions_are_automatically_in_strict_mode: { code: 1216, category: DiagnosticCategory.Error, key: "Type expected. '{0}' is a reserved word in strict mode. Class definitions are automatically in strict mode." },
         Export_assignment_is_not_supported_when_module_flag_is_system: { code: 1218, category: DiagnosticCategory.Error, key: "Export assignment is not supported when '--module' flag is 'system'." },
+        Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Specify_experimentalDecorators_to_remove_this_warning: { code: 1219, category: DiagnosticCategory.Error, key: "Experimental support for decorators is a feature that is subject to change in a future release. Specify '--experimentalDecorators' to remove this warning." },
         Duplicate_identifier_0: { code: 2300, category: DiagnosticCategory.Error, key: "Duplicate identifier '{0}'." },
         Initializer_of_instance_member_variable_0_cannot_reference_identifier_1_declared_in_the_constructor: { code: 2301, category: DiagnosticCategory.Error, key: "Initializer of instance member variable '{0}' cannot reference identifier '{1}' declared in the constructor." },
         Static_members_cannot_reference_class_type_parameters: { code: 2302, category: DiagnosticCategory.Error, key: "Static members cannot reference class type parameters." },
@@ -507,6 +508,9 @@ module ts {
         Specifies_the_end_of_line_sequence_to_be_used_when_emitting_files_Colon_CRLF_dos_or_LF_unix: { code: 6060, category: DiagnosticCategory.Message, key: "Specifies the end of line sequence to be used when emitting files: 'CRLF' (dos) or 'LF' (unix)." },
         NEWLINE: { code: 6061, category: DiagnosticCategory.Message, key: "NEWLINE" },
         Argument_for_newLine_option_must_be_CRLF_or_LF: { code: 6062, category: DiagnosticCategory.Error, key: "Argument for '--newLine' option must be 'CRLF' or 'LF'." },
+        Option_experimentalDecorators_must_also_be_specified_when_option_emitDecoratorMetadata_is_specified: { code: 6064, category: DiagnosticCategory.Error, key: "Option 'experimentalDecorators' must also be specified when option 'emitDecoratorMetadata' is specified." },
+        Enables_experimental_support_for_ES7_decorators: { code: 6065, category: DiagnosticCategory.Message, key: "Enables experimental support for ES7 decorators." },
+        Enables_experimental_support_for_emitting_type_metadata_for_decorators: { code: 6066, category: DiagnosticCategory.Message, key: "Enables experimental support for emitting type metadata for decorators." },
         Variable_0_implicitly_has_an_1_type: { code: 7005, category: DiagnosticCategory.Error, key: "Variable '{0}' implicitly has an '{1}' type." },
         Parameter_0_implicitly_has_an_1_type: { code: 7006, category: DiagnosticCategory.Error, key: "Parameter '{0}' implicitly has an '{1}' type." },
         Member_0_implicitly_has_an_1_type: { code: 7008, category: DiagnosticCategory.Error, key: "Member '{0}' implicitly has an '{1}' type." },
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 416936e741b..0ad8fc68528 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -683,6 +683,10 @@
         "category": "Error",
         "code": 1218
     },
+    "Experimental support for decorators is a feature that is subject to change in a future release. Specify '--experimentalDecorators' to remove this warning.": {
+        "category": "Error",
+        "code": 1219
+    },
 
     "Duplicate identifier '{0}'.": {
         "category": "Error",
@@ -2018,7 +2022,18 @@
         "category": "Error", 
         "code": 6062
     },
-
+    "Option 'experimentalDecorators' must also be specified when option 'emitDecoratorMetadata' is specified.": {
+        "category": "Error",
+        "code": 6064
+    },
+    "Enables experimental support for ES7 decorators.": {
+        "category": "Message",
+        "code": 6065
+    },
+    "Enables experimental support for emitting type metadata for decorators.": {
+        "category": "Message",
+        "code": 6066
+    },
 
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 32503de2566..9e0e250c987 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -635,6 +635,11 @@ module ts {
                     diagnostics.add(createCompilerDiagnostic(Diagnostics.Option_noEmit_cannot_be_specified_with_option_declaration));
                 }
             }
+            
+            if (options.emitDecoratorMetadata &&
+                !options.experimentalDecorators) {
+                diagnostics.add(createCompilerDiagnostic(Diagnostics.Option_experimentalDecorators_must_also_be_specified_when_option_emitDecoratorMetadata_is_specified));
+            }
         }
     }
 }
\ No newline at end of file
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index a6fa89846bb..848b51d721b 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -1677,6 +1677,7 @@ module ts {
         version?: boolean;
         watch?: boolean;
         isolatedModules?: boolean;
+        experimentalDecorators?: boolean;
         emitDecoratorMetadata?: boolean;
         /* @internal */ stripInternal?: boolean;
         [option: string]: string | number | boolean;
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index 63eff36b30a..f64fa57a41a 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -998,6 +998,10 @@ module Harness {
                                 options.target = <any>setting.value;
                             }
                             break;
+                            
+                        case 'experimentaldecorators':
+                            options.experimentalDecorators = setting.value === 'true';
+                            break;
 
                         case 'emitdecoratormetadata':
                             options.emitDecoratorMetadata = setting.value === 'true';
@@ -1510,7 +1514,7 @@ module Harness {
             "errortruncation", "usecasesensitivefilenames", "preserveconstenums",
             "includebuiltfile", "suppressimplicitanyindexerrors", "stripinternal",
             "isolatedmodules", "inlinesourcemap", "maproot", "sourceroot",
-            "inlinesources", "emitdecoratormetadata"];
+            "inlinesources", "emitdecoratormetadata", "experimentaldecorators"];
 
         function extractCompilerSettings(content: string): CompilerSetting[] {
 
diff --git a/tests/cases/compiler/classExpressionWithDecorator1.ts b/tests/cases/compiler/classExpressionWithDecorator1.ts
index 74b49456a36..67e9c8aa6ce 100644
--- a/tests/cases/compiler/classExpressionWithDecorator1.ts
+++ b/tests/cases/compiler/classExpressionWithDecorator1.ts
@@ -1 +1,2 @@
+// @experimentaldecorators: true
 var v = @decorate class C { static p = 1 };
\ No newline at end of file
diff --git a/tests/cases/compiler/noEmitHelpers2.ts b/tests/cases/compiler/noEmitHelpers2.ts
index df71f4fae82..ccc17f7066e 100644
--- a/tests/cases/compiler/noEmitHelpers2.ts
+++ b/tests/cases/compiler/noEmitHelpers2.ts
@@ -1,4 +1,5 @@
 // @noemithelpers: true
+// @experimentaldecorators: true
 // @emitdecoratormetadata: true
 // @target: es5
 
diff --git a/tests/cases/compiler/sourceMapValidationDecorators.ts b/tests/cases/compiler/sourceMapValidationDecorators.ts
index c8bd16be80f..898d3f729b2 100644
--- a/tests/cases/compiler/sourceMapValidationDecorators.ts
+++ b/tests/cases/compiler/sourceMapValidationDecorators.ts
@@ -1,5 +1,6 @@
 // @sourcemap: true
 // @target: es5
+// @experimentaldecorators: true
 declare function ClassDecorator1(target: Function): void;
 declare function ClassDecorator2(x: number): (target: Function) => void;
 declare function PropertyDecorator1(target: Object, key: string | symbol, descriptor?: PropertyDescriptor): void;
diff --git a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor1.ts b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor1.ts
index 7e80e9e637d..19abd8231d6 100644
--- a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor1.ts
+++ b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor1.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor2.ts b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor2.ts
index bbe58e72eb9..5250b42929c 100644
--- a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor2.ts
+++ b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor2.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor3.ts b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor3.ts
index bd1ce41bb12..4d7ccc6a825 100644
--- a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor3.ts
+++ b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor3.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor4.ts b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor4.ts
index 72259e5d212..35c15ae7a6f 100644
--- a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor4.ts
+++ b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor4.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor5.ts b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor5.ts
index ba5f82ab0ce..b32dd98ed2a 100644
--- a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor5.ts
+++ b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor5.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor6.ts b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor6.ts
index 686127858b0..ffbd2713621 100644
--- a/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor6.ts
+++ b/tests/cases/conformance/decorators/class/accessor/decoratorOnClassAccessor6.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/constructor/decoratorOnClassConstructor1.ts b/tests/cases/conformance/decorators/class/constructor/decoratorOnClassConstructor1.ts
index 4a39536e30b..b9ee9295744 100644
--- a/tests/cases/conformance/decorators/class/constructor/decoratorOnClassConstructor1.ts
+++ b/tests/cases/conformance/decorators/class/constructor/decoratorOnClassConstructor1.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/constructor/parameter/decoratorOnClassConstructorParameter1.ts b/tests/cases/conformance/decorators/class/constructor/parameter/decoratorOnClassConstructorParameter1.ts
index 3f4baabac7c..dbfd38c7896 100644
--- a/tests/cases/conformance/decorators/class/constructor/parameter/decoratorOnClassConstructorParameter1.ts
+++ b/tests/cases/conformance/decorators/class/constructor/parameter/decoratorOnClassConstructorParameter1.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec(target: Function, propertyKey: string | symbol, parameterIndex: number): void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/constructor/parameter/decoratorOnClassConstructorParameter4.ts b/tests/cases/conformance/decorators/class/constructor/parameter/decoratorOnClassConstructorParameter4.ts
index e58771fbebb..4e0373ff5d1 100644
--- a/tests/cases/conformance/decorators/class/constructor/parameter/decoratorOnClassConstructorParameter4.ts
+++ b/tests/cases/conformance/decorators/class/constructor/parameter/decoratorOnClassConstructorParameter4.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec(target: Function, propertyKey: string | symbol, parameterIndex: number): void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/decoratedClassFromExternalModule.ts b/tests/cases/conformance/decorators/class/decoratedClassFromExternalModule.ts
index cb622265b44..95f8bf4ab97 100644
--- a/tests/cases/conformance/decorators/class/decoratedClassFromExternalModule.ts
+++ b/tests/cases/conformance/decorators/class/decoratedClassFromExternalModule.ts
@@ -1,4 +1,5 @@
 // @target: es6
+// @experimentaldecorators: true
 // @Filename: decorated.ts
 function decorate() { }
 
diff --git a/tests/cases/conformance/decorators/class/decoratorChecksFunctionBodies.ts b/tests/cases/conformance/decorators/class/decoratorChecksFunctionBodies.ts
index 31f5fe82551..b1cbd1a679c 100644
--- a/tests/cases/conformance/decorators/class/decoratorChecksFunctionBodies.ts
+++ b/tests/cases/conformance/decorators/class/decoratorChecksFunctionBodies.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 
 // from #2971
 function func(s: string): void {
diff --git a/tests/cases/conformance/decorators/class/decoratorInstantiateModulesInFunctionBodies.ts b/tests/cases/conformance/decorators/class/decoratorInstantiateModulesInFunctionBodies.ts
index 7fa7ab8dd84..9163ed0c384 100644
--- a/tests/cases/conformance/decorators/class/decoratorInstantiateModulesInFunctionBodies.ts
+++ b/tests/cases/conformance/decorators/class/decoratorInstantiateModulesInFunctionBodies.ts
@@ -1,5 +1,6 @@
 // @target:es5
 // @module:commonjs
+// @experimentaldecorators: true
 // @filename: a.ts
 
 // from #3108
diff --git a/tests/cases/conformance/decorators/class/decoratorOnClass1.ts b/tests/cases/conformance/decorators/class/decoratorOnClass1.ts
index 1d3c87e7a6a..c1a729f56f3 100644
--- a/tests/cases/conformance/decorators/class/decoratorOnClass1.ts
+++ b/tests/cases/conformance/decorators/class/decoratorOnClass1.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec<T>(target: T): T;
 
 @dec
diff --git a/tests/cases/conformance/decorators/class/decoratorOnClass2.ts b/tests/cases/conformance/decorators/class/decoratorOnClass2.ts
index c82b9fe04a7..062ef391205 100644
--- a/tests/cases/conformance/decorators/class/decoratorOnClass2.ts
+++ b/tests/cases/conformance/decorators/class/decoratorOnClass2.ts
@@ -1,5 +1,6 @@
 // @target:es5
 // @module: commonjs
+// @experimentaldecorators: true
 declare function dec<T>(target: T): T;
 
 @dec
diff --git a/tests/cases/conformance/decorators/class/decoratorOnClass3.ts b/tests/cases/conformance/decorators/class/decoratorOnClass3.ts
index cf778380356..e410eaa1b07 100644
--- a/tests/cases/conformance/decorators/class/decoratorOnClass3.ts
+++ b/tests/cases/conformance/decorators/class/decoratorOnClass3.ts
@@ -1,5 +1,6 @@
 // @target:es5
 // @module: commonjs
+// @experimentaldecorators: true
 declare function dec<T>(target: T): T;
 
 export
diff --git a/tests/cases/conformance/decorators/class/decoratorOnClass4.ts b/tests/cases/conformance/decorators/class/decoratorOnClass4.ts
index e365df091fc..bebf595a170 100644
--- a/tests/cases/conformance/decorators/class/decoratorOnClass4.ts
+++ b/tests/cases/conformance/decorators/class/decoratorOnClass4.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec(): <T>(target: T) => T;
 
 @dec()
diff --git a/tests/cases/conformance/decorators/class/decoratorOnClass5.ts b/tests/cases/conformance/decorators/class/decoratorOnClass5.ts
index e365df091fc..bebf595a170 100644
--- a/tests/cases/conformance/decorators/class/decoratorOnClass5.ts
+++ b/tests/cases/conformance/decorators/class/decoratorOnClass5.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec(): <T>(target: T) => T;
 
 @dec()
diff --git a/tests/cases/conformance/decorators/class/decoratorOnClass8.ts b/tests/cases/conformance/decorators/class/decoratorOnClass8.ts
index a7227964180..bade386a56b 100644
--- a/tests/cases/conformance/decorators/class/decoratorOnClass8.ts
+++ b/tests/cases/conformance/decorators/class/decoratorOnClass8.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec(): (target: Function, paramIndex: number) => void;
 
 @dec()
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod1.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod1.ts
index 7216be210f1..418ace9a0dc 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod1.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod1.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod10.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod10.ts
index 03f75f16552..c4658cc6405 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod10.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod10.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec(target: Function, paramIndex: number): void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod11.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod11.ts
index 6f80fa00bca..058f8134880 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod11.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod11.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 module M {
     class C {
         decorator(target: Object, key: string): void { }
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod12.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod12.ts
index a9a2607c39b..9af80e32c46 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod12.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod12.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 module M {
     class S {
         decorator(target: Object, key: string): void { }
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod13.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod13.ts
index df0b847e99d..f41481d4ad0 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod13.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod13.ts
@@ -1,4 +1,5 @@
 // @target: ES6
+// @experimentaldecorators: true
 declare function dec(): <T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>) => TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod2.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod2.ts
index 7b7f089e4d4..8305ed1a448 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod2.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod2.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod3.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod3.ts
index aa80151cf83..b951bd5c8c9 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod3.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod3.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod4.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod4.ts
index 92b35ae6189..3d3ff2c8785 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod4.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod4.ts
@@ -1,4 +1,5 @@
 // @target: ES6
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod5.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod5.ts
index cd891b4231b..d91d4331ce0 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod5.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod5.ts
@@ -1,4 +1,5 @@
 // @target: ES6
+// @experimentaldecorators: true
 declare function dec(): <T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>) => TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod6.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod6.ts
index a1fa7005892..b3cd6ee75d4 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod6.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod6.ts
@@ -1,4 +1,5 @@
 // @target: ES6
+// @experimentaldecorators: true
 declare function dec(): <T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>) => TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod7.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod7.ts
index 4bf86aa4995..16915e9aaab 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod7.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod7.ts
@@ -1,4 +1,5 @@
 // @target: ES6
+// @experimentaldecorators: true
 declare function dec<T>(target: any, propertyKey: string, descriptor: TypedPropertyDescriptor<T>): TypedPropertyDescriptor<T>;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod8.ts b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod8.ts
index 9bd2c192c2d..73f58809420 100644
--- a/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod8.ts
+++ b/tests/cases/conformance/decorators/class/method/decoratorOnClassMethod8.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec<T>(target: T): T;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/method/parameter/decoratorOnClassMethodParameter1.ts b/tests/cases/conformance/decorators/class/method/parameter/decoratorOnClassMethodParameter1.ts
index e525933fb6a..18a7fff6dd0 100644
--- a/tests/cases/conformance/decorators/class/method/parameter/decoratorOnClassMethodParameter1.ts
+++ b/tests/cases/conformance/decorators/class/method/parameter/decoratorOnClassMethodParameter1.ts
@@ -1,4 +1,5 @@
 // @target:es5
+// @experimentaldecorators: true
 declare function dec(target: Function, propertyKey: string | symbol, parameterIndex: number): void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty1.ts b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty1.ts
index 0d8fd82225d..026949fb5b8 100644
--- a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty1.ts
+++ b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty1.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec(target: any, propertyKey: string): void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty10.ts b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty10.ts
index 4be77035692..2b10c0aec08 100644
--- a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty10.ts
+++ b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty10.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec(): <T>(target: any, propertyKey: string) => void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty11.ts b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty11.ts
index 60ea10189e2..eb720b20dff 100644
--- a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty11.ts
+++ b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty11.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec(): <T>(target: any, propertyKey: string) => void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty2.ts b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty2.ts
index dc2886e7dbd..01af3e6ee81 100644
--- a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty2.ts
+++ b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty2.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec(target: any, propertyKey: string): void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty3.ts b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty3.ts
index cf58b4b71ec..55fd6fe93e1 100644
--- a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty3.ts
+++ b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty3.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec(target: any, propertyKey: string): void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty6.ts b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty6.ts
index 1dd184419af..412a592ece1 100644
--- a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty6.ts
+++ b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty6.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec(target: Function): void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty7.ts b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty7.ts
index d82ca6eb2eb..0e11e103ce7 100644
--- a/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty7.ts
+++ b/tests/cases/conformance/decorators/class/property/decoratorOnClassProperty7.ts
@@ -1,4 +1,5 @@
 // @target: ES5
+// @experimentaldecorators: true
 declare function dec(target: Function, propertyKey: string | symbol, paramIndex: number): void;
 
 class C {
diff --git a/tests/cases/conformance/decorators/missingDecoratorType.ts b/tests/cases/conformance/decorators/missingDecoratorType.ts
index 1407e00b7a3..905edaf0756 100644
--- a/tests/cases/conformance/decorators/missingDecoratorType.ts
+++ b/tests/cases/conformance/decorators/missingDecoratorType.ts
@@ -1,4 +1,5 @@
-// @target: ES5
+// @target: ES5
+// @experimentaldecorators: true
 // @noLib: true
 
 // @Filename: a.ts
@@ -11,8 +12,7 @@ interface Function { }
 interface RegExp { }
 interface IArguments { }
 
-// @Filename: b.ts
-/// <reference path="a.ts" />
+// @Filename: b.ts
 declare var dec: any;
 
 @dec