diff --git a/lib/tsc.js b/lib/tsc.js
index 0e3d7285ac3..69b9ab5e477 100644
--- a/lib/tsc.js
+++ b/lib/tsc.js
@@ -24051,6 +24051,7 @@ var ts;
                                 var parameter = local_1.valueDeclaration;
                                 if (compilerOptions.noUnusedParameters &&
                                     !ts.isParameterPropertyDeclaration(parameter) &&
+                                    !parameterIsThisKeyword(parameter) &&
                                     !parameterNameStartsWithUnderscore(parameter)) {
                                     error(local_1.valueDeclaration.name, ts.Diagnostics._0_is_declared_but_never_used, local_1.name);
                                 }
@@ -24066,6 +24067,9 @@ var ts;
                 }
             }
         }
+        function parameterIsThisKeyword(parameter) {
+            return parameter.name && parameter.name.originalKeywordKind === 97;
+        }
         function parameterNameStartsWithUnderscore(parameter) {
             return parameter.name && parameter.name.kind === 69 && parameter.name.text.charCodeAt(0) === 95;
         }
diff --git a/lib/tsserver.js b/lib/tsserver.js
index af6ee897902..68bceb54bb9 100644
--- a/lib/tsserver.js
+++ b/lib/tsserver.js
@@ -24969,6 +24969,7 @@ var ts;
                                 var parameter = local_1.valueDeclaration;
                                 if (compilerOptions.noUnusedParameters &&
                                     !ts.isParameterPropertyDeclaration(parameter) &&
+                                    !parameterIsThisKeyword(parameter) &&
                                     !parameterNameStartsWithUnderscore(parameter)) {
                                     error(local_1.valueDeclaration.name, ts.Diagnostics._0_is_declared_but_never_used, local_1.name);
                                 }
@@ -24984,6 +24985,9 @@ var ts;
                 }
             }
         }
+        function parameterIsThisKeyword(parameter) {
+            return parameter.name && parameter.name.originalKeywordKind === 97;
+        }
         function parameterNameStartsWithUnderscore(parameter) {
             return parameter.name && parameter.name.kind === 69 && parameter.name.text.charCodeAt(0) === 95;
         }
@@ -50793,7 +50797,6 @@ var ts;
                 if (isOpen === void 0) { isOpen = false; }
                 this.host = host;
                 this.fileName = fileName;
-                this.content = content;
                 this.isOpen = isOpen;
                 this.children = [];
                 this.formatCodeOptions = ts.clone(CompilerService.getDefaultFormatCodeOptions(this.host));
@@ -53197,7 +53200,7 @@ var ts;
             return this.shimHost.getCurrentDirectory();
         };
         LanguageServiceShimHostAdapter.prototype.getDirectories = function (path) {
-            return this.shimHost.getDirectories(path);
+            return JSON.parse(this.shimHost.getDirectories(path));
         };
         LanguageServiceShimHostAdapter.prototype.getDefaultLibFileName = function (options) {
             return this.shimHost.getDefaultLibFileName(JSON.stringify(options));
diff --git a/lib/tsserverlibrary.d.ts b/lib/tsserverlibrary.d.ts
index 2c9fffcfcfb..1e0cefac78b 100644
--- a/lib/tsserverlibrary.d.ts
+++ b/lib/tsserverlibrary.d.ts
@@ -8388,7 +8388,6 @@ declare namespace ts.server {
     class ScriptInfo {
         private host;
         fileName: string;
-        content: string;
         isOpen: boolean;
         svc: ScriptVersionCache;
         children: ScriptInfo[];
@@ -8729,7 +8728,7 @@ declare namespace ts {
         getLocalizedDiagnosticMessages(): string;
         getCancellationToken(): HostCancellationToken;
         getCurrentDirectory(): string;
-        getDirectories(path: string): string[];
+        getDirectories(path: string): string;
         getDefaultLibFileName(options: string): string;
         getNewLine?(): string;
         getProjectVersion?(): string;
diff --git a/lib/tsserverlibrary.js b/lib/tsserverlibrary.js
index 5dafd5528a8..f0bfd0f4f3e 100644
--- a/lib/tsserverlibrary.js
+++ b/lib/tsserverlibrary.js
@@ -24969,6 +24969,7 @@ var ts;
                                 var parameter = local_1.valueDeclaration;
                                 if (compilerOptions.noUnusedParameters &&
                                     !ts.isParameterPropertyDeclaration(parameter) &&
+                                    !parameterIsThisKeyword(parameter) &&
                                     !parameterNameStartsWithUnderscore(parameter)) {
                                     error(local_1.valueDeclaration.name, ts.Diagnostics._0_is_declared_but_never_used, local_1.name);
                                 }
@@ -24984,6 +24985,9 @@ var ts;
                 }
             }
         }
+        function parameterIsThisKeyword(parameter) {
+            return parameter.name && parameter.name.originalKeywordKind === 97;
+        }
         function parameterNameStartsWithUnderscore(parameter) {
             return parameter.name && parameter.name.kind === 69 && parameter.name.text.charCodeAt(0) === 95;
         }
@@ -50793,7 +50797,6 @@ var ts;
                 if (isOpen === void 0) { isOpen = false; }
                 this.host = host;
                 this.fileName = fileName;
-                this.content = content;
                 this.isOpen = isOpen;
                 this.children = [];
                 this.formatCodeOptions = ts.clone(CompilerService.getDefaultFormatCodeOptions(this.host));
@@ -52963,7 +52966,7 @@ var ts;
             return this.shimHost.getCurrentDirectory();
         };
         LanguageServiceShimHostAdapter.prototype.getDirectories = function (path) {
-            return this.shimHost.getDirectories(path);
+            return JSON.parse(this.shimHost.getDirectories(path));
         };
         LanguageServiceShimHostAdapter.prototype.getDefaultLibFileName = function (options) {
             return this.shimHost.getDefaultLibFileName(JSON.stringify(options));
diff --git a/lib/typescript.js b/lib/typescript.js
index 22cbe79129c..3b28d8f0e67 100644
--- a/lib/typescript.js
+++ b/lib/typescript.js
@@ -29341,6 +29341,7 @@ var ts;
                                 var parameter = local_1.valueDeclaration;
                                 if (compilerOptions.noUnusedParameters &&
                                     !ts.isParameterPropertyDeclaration(parameter) &&
+                                    !parameterIsThisKeyword(parameter) &&
                                     !parameterNameStartsWithUnderscore(parameter)) {
                                     error(local_1.valueDeclaration.name, ts.Diagnostics._0_is_declared_but_never_used, local_1.name);
                                 }
@@ -29356,6 +29357,9 @@ var ts;
                 }
             }
         }
+        function parameterIsThisKeyword(parameter) {
+            return parameter.name && parameter.name.originalKeywordKind === 97 /* ThisKeyword */;
+        }
         function parameterNameStartsWithUnderscore(parameter) {
             return parameter.name && parameter.name.kind === 69 /* Identifier */ && parameter.name.text.charCodeAt(0) === 95 /* _ */;
         }
@@ -59701,7 +59705,7 @@ var ts;
             return this.shimHost.getCurrentDirectory();
         };
         LanguageServiceShimHostAdapter.prototype.getDirectories = function (path) {
-            return this.shimHost.getDirectories(path);
+            return JSON.parse(this.shimHost.getDirectories(path));
         };
         LanguageServiceShimHostAdapter.prototype.getDefaultLibFileName = function (options) {
             return this.shimHost.getDefaultLibFileName(JSON.stringify(options));
diff --git a/lib/typescriptServices.js b/lib/typescriptServices.js
index 22cbe79129c..3b28d8f0e67 100644
--- a/lib/typescriptServices.js
+++ b/lib/typescriptServices.js
@@ -29341,6 +29341,7 @@ var ts;
                                 var parameter = local_1.valueDeclaration;
                                 if (compilerOptions.noUnusedParameters &&
                                     !ts.isParameterPropertyDeclaration(parameter) &&
+                                    !parameterIsThisKeyword(parameter) &&
                                     !parameterNameStartsWithUnderscore(parameter)) {
                                     error(local_1.valueDeclaration.name, ts.Diagnostics._0_is_declared_but_never_used, local_1.name);
                                 }
@@ -29356,6 +29357,9 @@ var ts;
                 }
             }
         }
+        function parameterIsThisKeyword(parameter) {
+            return parameter.name && parameter.name.originalKeywordKind === 97 /* ThisKeyword */;
+        }
         function parameterNameStartsWithUnderscore(parameter) {
             return parameter.name && parameter.name.kind === 69 /* Identifier */ && parameter.name.text.charCodeAt(0) === 95 /* _ */;
         }
@@ -59701,7 +59705,7 @@ var ts;
             return this.shimHost.getCurrentDirectory();
         };
         LanguageServiceShimHostAdapter.prototype.getDirectories = function (path) {
-            return this.shimHost.getDirectories(path);
+            return JSON.parse(this.shimHost.getDirectories(path));
         };
         LanguageServiceShimHostAdapter.prototype.getDefaultLibFileName = function (options) {
             return this.shimHost.getDefaultLibFileName(JSON.stringify(options));
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index e842f008bbe..d68502dc8e8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -13277,7 +13277,7 @@ namespace ts {
                         checkAsyncFunctionReturnType(<FunctionLikeDeclaration>node);
                     }
                 }
-                if (!(<FunctionDeclaration>node).body) {
+                if (noUnusedIdentifiers && !(<FunctionDeclaration>node).body) {
                     checkUnusedTypeParameters(node);
                 }
             }
@@ -14612,8 +14612,15 @@ namespace ts {
         function checkUnusedTypeParameters(node: ClassDeclaration | ClassExpression | FunctionDeclaration | MethodDeclaration | FunctionExpression | ArrowFunction | ConstructorDeclaration | SignatureDeclaration | InterfaceDeclaration) {
             if (compilerOptions.noUnusedLocals && !isInAmbientContext(node)) {
                 if (node.typeParameters) {
+                    // Only report errors on the last declaration for the type parameter container;
+                    // this ensures that all uses have been accounted for.
+                    const symbol = getSymbolOfNode(node);
+                    const lastDeclaration = symbol && symbol.declarations && lastOrUndefined(symbol.declarations);
+                    if (lastDeclaration !== node) {
+                        return;
+                    }
                     for (const typeParameter of node.typeParameters) {
-                        if (!typeParameter.symbol.isReferenced) {
+                        if (!getMergedSymbol(typeParameter.symbol).isReferenced) {
                             error(typeParameter.name, Diagnostics._0_is_declared_but_never_used, typeParameter.symbol.name);
                         }
                     }
@@ -16122,7 +16129,7 @@ namespace ts {
 
             if (produceDiagnostics) {
                 checkTypeForDuplicateIndexSignatures(node);
-                checkUnusedTypeParameters(node);
+                registerForUnusedIdentifiersCheck(node);
             }
         }
 
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 6adf76903fb..a801effd49a 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -2749,7 +2749,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
              *   if we should also export the value after its it changed
              * - check if node is a source level declaration to emit it differently,
              *   i.e non-exported variable statement 'var x = 1' is hoisted so
-             *   we we emit variable statement 'var' should be dropped.
+             *   when we emit variable statement 'var' should be dropped.
              */
             function isSourceFileLevelDeclarationInSystemJsModule(node: Node, isExported: boolean): boolean {
                 if (!node || !isCurrentFileSystemExternalModule()) {
@@ -5503,16 +5503,15 @@ const _super = (function (geti, seti) {
                             write("export ");
                         }
 
-                        if (!isHoistedDeclarationInSystemModule) {
-                            write("let ");
-                        }
                         if (decoratedClassAlias !== undefined) {
-                            write(`${decoratedClassAlias}`);
+                            write(`let ${decoratedClassAlias}`);
                         }
                         else {
+                            if (!isHoistedDeclarationInSystemModule) {
+                                write("let ");
+                            }
                             emitDeclarationName(node);
                         }
-
                         write(" = ");
                     }
                     else if (isES6ExportedDeclaration(node)) {
@@ -5530,7 +5529,9 @@ const _super = (function (geti, seti) {
                 //
                 // We'll emit:
                 //
-                //      (_temp = class C { ... }, _temp.a = 1, _temp.b = 2, _temp)
+                //      let C_1 = class C{};
+                //      C_1.a = 1;
+                //      C_1.b = 2; // so forth and so on
                 //
                 // This keeps the expression as an expression, while ensuring that the static parts
                 // of it have been initialized by the time it is used.
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index de4f6bc526c..d0df5e86550 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2912,7 +2912,6 @@ namespace ts {
         getCancellationToken?(): CancellationToken;
         getDefaultLibFileName(options: CompilerOptions): string;
         getDefaultLibLocation?(): string;
-        getDefaultTypeDirectiveNames?(rootPath: string): string[];
         writeFile: WriteFileCallback;
         getCurrentDirectory(): string;
         getDirectories(path: string): string[];
diff --git a/tests/baselines/reference/decoratedClassExportsCommonJS1.js b/tests/baselines/reference/decoratedClassExportsCommonJS1.js
new file mode 100644
index 00000000000..4a04d724f0c
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsCommonJS1.js
@@ -0,0 +1,28 @@
+//// [decoratedClassExportsCommonJS1.ts]
+declare var Something: any;
+@Something({ v: () => Testing123 })
+export class Testing123 {
+    static prop0: string;
+    static prop1 = Testing123.prop0;
+}
+
+//// [decoratedClassExportsCommonJS1.js]
+"use strict";
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+var __metadata = (this && this.__metadata) || function (k, v) {
+    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+};
+let Testing123_1 = class Testing123 {
+};
+let Testing123 = Testing123_1;
+Testing123.prop1 = Testing123.prop0;
+Testing123 = Testing123_1 = __decorate([
+    Something({ v: () => Testing123 }), 
+    __metadata('design:paramtypes', [])
+], Testing123);
+exports.Testing123 = Testing123;
diff --git a/tests/baselines/reference/decoratedClassExportsCommonJS1.symbols b/tests/baselines/reference/decoratedClassExportsCommonJS1.symbols
new file mode 100644
index 00000000000..3381ef7c06a
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsCommonJS1.symbols
@@ -0,0 +1,21 @@
+=== tests/cases/conformance/decorators/class/decoratedClassExportsCommonJS1.ts ===
+declare var Something: any;
+>Something : Symbol(Something, Decl(decoratedClassExportsCommonJS1.ts, 0, 11))
+
+@Something({ v: () => Testing123 })
+>Something : Symbol(Something, Decl(decoratedClassExportsCommonJS1.ts, 0, 11))
+>v : Symbol(v, Decl(decoratedClassExportsCommonJS1.ts, 1, 12))
+>Testing123 : Symbol(Testing123, Decl(decoratedClassExportsCommonJS1.ts, 0, 27))
+
+export class Testing123 {
+>Testing123 : Symbol(Testing123, Decl(decoratedClassExportsCommonJS1.ts, 0, 27))
+
+    static prop0: string;
+>prop0 : Symbol(Testing123.prop0, Decl(decoratedClassExportsCommonJS1.ts, 2, 25))
+
+    static prop1 = Testing123.prop0;
+>prop1 : Symbol(Testing123.prop1, Decl(decoratedClassExportsCommonJS1.ts, 3, 25))
+>Testing123.prop0 : Symbol(Testing123.prop0, Decl(decoratedClassExportsCommonJS1.ts, 2, 25))
+>Testing123 : Symbol(Testing123, Decl(decoratedClassExportsCommonJS1.ts, 0, 27))
+>prop0 : Symbol(Testing123.prop0, Decl(decoratedClassExportsCommonJS1.ts, 2, 25))
+}
diff --git a/tests/baselines/reference/decoratedClassExportsCommonJS1.types b/tests/baselines/reference/decoratedClassExportsCommonJS1.types
new file mode 100644
index 00000000000..0142adb654f
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsCommonJS1.types
@@ -0,0 +1,24 @@
+=== tests/cases/conformance/decorators/class/decoratedClassExportsCommonJS1.ts ===
+declare var Something: any;
+>Something : any
+
+@Something({ v: () => Testing123 })
+>Something({ v: () => Testing123 }) : any
+>Something : any
+>{ v: () => Testing123 } : { v: () => typeof Testing123; }
+>v : () => typeof Testing123
+>() => Testing123 : () => typeof Testing123
+>Testing123 : typeof Testing123
+
+export class Testing123 {
+>Testing123 : Testing123
+
+    static prop0: string;
+>prop0 : string
+
+    static prop1 = Testing123.prop0;
+>prop1 : string
+>Testing123.prop0 : string
+>Testing123 : typeof Testing123
+>prop0 : string
+}
diff --git a/tests/baselines/reference/decoratedClassExportsCommonJS2.js b/tests/baselines/reference/decoratedClassExportsCommonJS2.js
new file mode 100644
index 00000000000..c5e8eb9aa29
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsCommonJS2.js
@@ -0,0 +1,26 @@
+//// [a.ts]
+
+declare function forwardRef(x: any): any;
+declare var Something: any;
+@Something({ v: () => Testing123 })
+export class Testing123 { }
+
+//// [a.js]
+"use strict";
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+var __metadata = (this && this.__metadata) || function (k, v) {
+    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+};
+let Testing123_1 = class Testing123 {
+};
+let Testing123 = Testing123_1;
+Testing123 = Testing123_1 = __decorate([
+    Something({ v: () => Testing123 }), 
+    __metadata('design:paramtypes', [])
+], Testing123);
+exports.Testing123 = Testing123;
diff --git a/tests/baselines/reference/decoratedClassExportsCommonJS2.symbols b/tests/baselines/reference/decoratedClassExportsCommonJS2.symbols
new file mode 100644
index 00000000000..8f587c1bff1
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsCommonJS2.symbols
@@ -0,0 +1,17 @@
+=== tests/cases/conformance/decorators/class/a.ts ===
+
+declare function forwardRef(x: any): any;
+>forwardRef : Symbol(forwardRef, Decl(a.ts, 0, 0))
+>x : Symbol(x, Decl(a.ts, 1, 28))
+
+declare var Something: any;
+>Something : Symbol(Something, Decl(a.ts, 2, 11))
+
+@Something({ v: () => Testing123 })
+>Something : Symbol(Something, Decl(a.ts, 2, 11))
+>v : Symbol(v, Decl(a.ts, 3, 12))
+>Testing123 : Symbol(Testing123, Decl(a.ts, 2, 27))
+
+export class Testing123 { }
+>Testing123 : Symbol(Testing123, Decl(a.ts, 2, 27))
+
diff --git a/tests/baselines/reference/decoratedClassExportsCommonJS2.types b/tests/baselines/reference/decoratedClassExportsCommonJS2.types
new file mode 100644
index 00000000000..eba793247de
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsCommonJS2.types
@@ -0,0 +1,20 @@
+=== tests/cases/conformance/decorators/class/a.ts ===
+
+declare function forwardRef(x: any): any;
+>forwardRef : (x: any) => any
+>x : any
+
+declare var Something: any;
+>Something : any
+
+@Something({ v: () => Testing123 })
+>Something({ v: () => Testing123 }) : any
+>Something : any
+>{ v: () => Testing123 } : { v: () => typeof Testing123; }
+>v : () => typeof Testing123
+>() => Testing123 : () => typeof Testing123
+>Testing123 : typeof Testing123
+
+export class Testing123 { }
+>Testing123 : Testing123
+
diff --git a/tests/baselines/reference/decoratedClassExportsSystem1.js b/tests/baselines/reference/decoratedClassExportsSystem1.js
new file mode 100644
index 00000000000..1730ba4460f
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsSystem1.js
@@ -0,0 +1,39 @@
+//// [a.ts]
+
+declare function forwardRef(x: any): any;
+declare var Something: any;
+@Something({ v: () => Testing123 })
+export class Testing123 {
+    static prop0: string;
+    static prop1 = Testing123.prop0;
+}
+
+//// [a.js]
+System.register([], function(exports_1, context_1) {
+    "use strict";
+    var __moduleName = context_1 && context_1.id;
+    var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+        var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+        if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+        else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+        return c > 3 && r && Object.defineProperty(target, key, r), r;
+    };
+    var __metadata = (this && this.__metadata) || function (k, v) {
+        if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+    };
+    var Testing123;
+    return {
+        setters:[],
+        execute: function() {
+            let Testing123_1 = class Testing123 {
+            };
+            let Testing123 = Testing123_1;
+            Testing123.prop1 = Testing123.prop0;
+            Testing123 = Testing123_1 = __decorate([
+                Something({ v: () => Testing123 }), 
+                __metadata('design:paramtypes', [])
+            ], Testing123);
+            exports_1("Testing123", Testing123);
+        }
+    }
+});
diff --git a/tests/baselines/reference/decoratedClassExportsSystem1.symbols b/tests/baselines/reference/decoratedClassExportsSystem1.symbols
new file mode 100644
index 00000000000..559f78624e3
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsSystem1.symbols
@@ -0,0 +1,26 @@
+=== tests/cases/conformance/decorators/class/a.ts ===
+
+declare function forwardRef(x: any): any;
+>forwardRef : Symbol(forwardRef, Decl(a.ts, 0, 0))
+>x : Symbol(x, Decl(a.ts, 1, 28))
+
+declare var Something: any;
+>Something : Symbol(Something, Decl(a.ts, 2, 11))
+
+@Something({ v: () => Testing123 })
+>Something : Symbol(Something, Decl(a.ts, 2, 11))
+>v : Symbol(v, Decl(a.ts, 3, 12))
+>Testing123 : Symbol(Testing123, Decl(a.ts, 2, 27))
+
+export class Testing123 {
+>Testing123 : Symbol(Testing123, Decl(a.ts, 2, 27))
+
+    static prop0: string;
+>prop0 : Symbol(Testing123.prop0, Decl(a.ts, 4, 25))
+
+    static prop1 = Testing123.prop0;
+>prop1 : Symbol(Testing123.prop1, Decl(a.ts, 5, 25))
+>Testing123.prop0 : Symbol(Testing123.prop0, Decl(a.ts, 4, 25))
+>Testing123 : Symbol(Testing123, Decl(a.ts, 2, 27))
+>prop0 : Symbol(Testing123.prop0, Decl(a.ts, 4, 25))
+}
diff --git a/tests/baselines/reference/decoratedClassExportsSystem1.types b/tests/baselines/reference/decoratedClassExportsSystem1.types
new file mode 100644
index 00000000000..1cc69e8b680
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsSystem1.types
@@ -0,0 +1,29 @@
+=== tests/cases/conformance/decorators/class/a.ts ===
+
+declare function forwardRef(x: any): any;
+>forwardRef : (x: any) => any
+>x : any
+
+declare var Something: any;
+>Something : any
+
+@Something({ v: () => Testing123 })
+>Something({ v: () => Testing123 }) : any
+>Something : any
+>{ v: () => Testing123 } : { v: () => typeof Testing123; }
+>v : () => typeof Testing123
+>() => Testing123 : () => typeof Testing123
+>Testing123 : typeof Testing123
+
+export class Testing123 {
+>Testing123 : Testing123
+
+    static prop0: string;
+>prop0 : string
+
+    static prop1 = Testing123.prop0;
+>prop1 : string
+>Testing123.prop0 : string
+>Testing123 : typeof Testing123
+>prop0 : string
+}
diff --git a/tests/baselines/reference/decoratedClassExportsSystem2.js b/tests/baselines/reference/decoratedClassExportsSystem2.js
new file mode 100644
index 00000000000..b4d34de2958
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsSystem2.js
@@ -0,0 +1,35 @@
+//// [a.ts]
+
+declare function forwardRef(x: any): any;
+declare var Something: any;
+@Something({ v: () => Testing123 })
+export class Testing123 { }
+
+//// [a.js]
+System.register([], function(exports_1, context_1) {
+    "use strict";
+    var __moduleName = context_1 && context_1.id;
+    var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+        var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+        if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+        else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+        return c > 3 && r && Object.defineProperty(target, key, r), r;
+    };
+    var __metadata = (this && this.__metadata) || function (k, v) {
+        if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+    };
+    var Testing123;
+    return {
+        setters:[],
+        execute: function() {
+            let Testing123_1 = class Testing123 {
+            };
+            let Testing123 = Testing123_1;
+            Testing123 = Testing123_1 = __decorate([
+                Something({ v: () => Testing123 }), 
+                __metadata('design:paramtypes', [])
+            ], Testing123);
+            exports_1("Testing123", Testing123);
+        }
+    }
+});
diff --git a/tests/baselines/reference/decoratedClassExportsSystem2.symbols b/tests/baselines/reference/decoratedClassExportsSystem2.symbols
new file mode 100644
index 00000000000..8f587c1bff1
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsSystem2.symbols
@@ -0,0 +1,17 @@
+=== tests/cases/conformance/decorators/class/a.ts ===
+
+declare function forwardRef(x: any): any;
+>forwardRef : Symbol(forwardRef, Decl(a.ts, 0, 0))
+>x : Symbol(x, Decl(a.ts, 1, 28))
+
+declare var Something: any;
+>Something : Symbol(Something, Decl(a.ts, 2, 11))
+
+@Something({ v: () => Testing123 })
+>Something : Symbol(Something, Decl(a.ts, 2, 11))
+>v : Symbol(v, Decl(a.ts, 3, 12))
+>Testing123 : Symbol(Testing123, Decl(a.ts, 2, 27))
+
+export class Testing123 { }
+>Testing123 : Symbol(Testing123, Decl(a.ts, 2, 27))
+
diff --git a/tests/baselines/reference/decoratedClassExportsSystem2.types b/tests/baselines/reference/decoratedClassExportsSystem2.types
new file mode 100644
index 00000000000..eba793247de
--- /dev/null
+++ b/tests/baselines/reference/decoratedClassExportsSystem2.types
@@ -0,0 +1,20 @@
+=== tests/cases/conformance/decorators/class/a.ts ===
+
+declare function forwardRef(x: any): any;
+>forwardRef : (x: any) => any
+>x : any
+
+declare var Something: any;
+>Something : any
+
+@Something({ v: () => Testing123 })
+>Something({ v: () => Testing123 }) : any
+>Something : any
+>{ v: () => Testing123 } : { v: () => typeof Testing123; }
+>v : () => typeof Testing123
+>() => Testing123 : () => typeof Testing123
+>Testing123 : typeof Testing123
+
+export class Testing123 { }
+>Testing123 : Testing123
+
diff --git a/tests/baselines/reference/unusedTypeParameters6.js b/tests/baselines/reference/unusedTypeParameters6.js
new file mode 100644
index 00000000000..4c2b3a9d0ba
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters6.js
@@ -0,0 +1,16 @@
+//// [tests/cases/compiler/unusedTypeParameters6.ts] ////
+
+//// [a.ts]
+
+class C<T> { }
+
+//// [b.ts]
+interface C<T> { a: T; }
+
+//// [a.js]
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+//// [b.js]
diff --git a/tests/baselines/reference/unusedTypeParameters6.symbols b/tests/baselines/reference/unusedTypeParameters6.symbols
new file mode 100644
index 00000000000..bf20b44d347
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters6.symbols
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/a.ts ===
+
+class C<T> { }
+>C : Symbol(C, Decl(a.ts, 0, 0), Decl(b.ts, 0, 0))
+>T : Symbol(T, Decl(a.ts, 1, 8), Decl(b.ts, 0, 12))
+
+=== tests/cases/compiler/b.ts ===
+interface C<T> { a: T; }
+>C : Symbol(C, Decl(a.ts, 0, 0), Decl(b.ts, 0, 0))
+>T : Symbol(T, Decl(a.ts, 1, 8), Decl(b.ts, 0, 12))
+>a : Symbol(C.a, Decl(b.ts, 0, 16))
+>T : Symbol(T, Decl(a.ts, 1, 8), Decl(b.ts, 0, 12))
+
diff --git a/tests/baselines/reference/unusedTypeParameters6.types b/tests/baselines/reference/unusedTypeParameters6.types
new file mode 100644
index 00000000000..165862c0080
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters6.types
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/a.ts ===
+
+class C<T> { }
+>C : C<T>
+>T : T
+
+=== tests/cases/compiler/b.ts ===
+interface C<T> { a: T; }
+>C : C<T>
+>T : T
+>a : T
+>T : T
+
diff --git a/tests/baselines/reference/unusedTypeParameters7.js b/tests/baselines/reference/unusedTypeParameters7.js
new file mode 100644
index 00000000000..d63f7a0edc3
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters7.js
@@ -0,0 +1,16 @@
+//// [tests/cases/compiler/unusedTypeParameters7.ts] ////
+
+//// [a.ts]
+
+class C<T> { a: T; }
+
+//// [b.ts]
+interface C<T> { }
+
+//// [a.js]
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+//// [b.js]
diff --git a/tests/baselines/reference/unusedTypeParameters7.symbols b/tests/baselines/reference/unusedTypeParameters7.symbols
new file mode 100644
index 00000000000..79704b437a6
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters7.symbols
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/a.ts ===
+
+class C<T> { a: T; }
+>C : Symbol(C, Decl(a.ts, 0, 0), Decl(b.ts, 0, 0))
+>T : Symbol(T, Decl(a.ts, 1, 8), Decl(b.ts, 0, 12))
+>a : Symbol(C.a, Decl(a.ts, 1, 12))
+>T : Symbol(T, Decl(a.ts, 1, 8), Decl(b.ts, 0, 12))
+
+=== tests/cases/compiler/b.ts ===
+interface C<T> { }
+>C : Symbol(C, Decl(a.ts, 0, 0), Decl(b.ts, 0, 0))
+>T : Symbol(T, Decl(a.ts, 1, 8), Decl(b.ts, 0, 12))
+
diff --git a/tests/baselines/reference/unusedTypeParameters7.types b/tests/baselines/reference/unusedTypeParameters7.types
new file mode 100644
index 00000000000..a52b4cee7ec
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters7.types
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/a.ts ===
+
+class C<T> { a: T; }
+>C : C<T>
+>T : T
+>a : T
+>T : T
+
+=== tests/cases/compiler/b.ts ===
+interface C<T> { }
+>C : C<T>
+>T : T
+
diff --git a/tests/baselines/reference/unusedTypeParameters8.errors.txt b/tests/baselines/reference/unusedTypeParameters8.errors.txt
new file mode 100644
index 00000000000..d7928d36900
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters8.errors.txt
@@ -0,0 +1,11 @@
+tests/cases/compiler/b.ts(1,13): error TS6133: 'T' is declared but never used.
+
+
+==== tests/cases/compiler/a.ts (0 errors) ====
+    
+    class C<T> { }
+    
+==== tests/cases/compiler/b.ts (1 errors) ====
+    interface C<T> { }
+                ~
+!!! error TS6133: 'T' is declared but never used.
\ No newline at end of file
diff --git a/tests/baselines/reference/unusedTypeParameters8.js b/tests/baselines/reference/unusedTypeParameters8.js
new file mode 100644
index 00000000000..0c34373d315
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters8.js
@@ -0,0 +1,16 @@
+//// [tests/cases/compiler/unusedTypeParameters8.ts] ////
+
+//// [a.ts]
+
+class C<T> { }
+
+//// [b.ts]
+interface C<T> { }
+
+//// [a.js]
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+//// [b.js]
diff --git a/tests/baselines/reference/unusedTypeParameters9.js b/tests/baselines/reference/unusedTypeParameters9.js
new file mode 100644
index 00000000000..8d82921b076
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters9.js
@@ -0,0 +1,30 @@
+//// [unusedTypeParameters9.ts]
+
+// clas + interface
+class C1<T> { }
+interface C1<T> { a: T; }
+
+// interface + class
+class C2<T> { a: T; }
+interface C2<T> { }
+
+// interfaces
+interface C3<T> { a(c: (p: T) => void): void; }
+interface C3<T> { b: string; }
+interface C3<T> { c: number; }
+interface C3<T> { d: boolean;  }
+interface C3<T> { e: any; }
+
+//// [unusedTypeParameters9.js]
+// clas + interface
+var C1 = (function () {
+    function C1() {
+    }
+    return C1;
+}());
+// interface + class
+var C2 = (function () {
+    function C2() {
+    }
+    return C2;
+}());
diff --git a/tests/baselines/reference/unusedTypeParameters9.symbols b/tests/baselines/reference/unusedTypeParameters9.symbols
new file mode 100644
index 00000000000..6c4f6aab71c
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters9.symbols
@@ -0,0 +1,53 @@
+=== tests/cases/compiler/unusedTypeParameters9.ts ===
+
+// clas + interface
+class C1<T> { }
+>C1 : Symbol(C1, Decl(unusedTypeParameters9.ts, 0, 0), Decl(unusedTypeParameters9.ts, 2, 15))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 2, 9), Decl(unusedTypeParameters9.ts, 3, 13))
+
+interface C1<T> { a: T; }
+>C1 : Symbol(C1, Decl(unusedTypeParameters9.ts, 0, 0), Decl(unusedTypeParameters9.ts, 2, 15))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 2, 9), Decl(unusedTypeParameters9.ts, 3, 13))
+>a : Symbol(C1.a, Decl(unusedTypeParameters9.ts, 3, 17))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 2, 9), Decl(unusedTypeParameters9.ts, 3, 13))
+
+// interface + class
+class C2<T> { a: T; }
+>C2 : Symbol(C2, Decl(unusedTypeParameters9.ts, 3, 25), Decl(unusedTypeParameters9.ts, 6, 21))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 6, 9), Decl(unusedTypeParameters9.ts, 7, 13))
+>a : Symbol(C2.a, Decl(unusedTypeParameters9.ts, 6, 13))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 6, 9), Decl(unusedTypeParameters9.ts, 7, 13))
+
+interface C2<T> { }
+>C2 : Symbol(C2, Decl(unusedTypeParameters9.ts, 3, 25), Decl(unusedTypeParameters9.ts, 6, 21))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 6, 9), Decl(unusedTypeParameters9.ts, 7, 13))
+
+// interfaces
+interface C3<T> { a(c: (p: T) => void): void; }
+>C3 : Symbol(C3, Decl(unusedTypeParameters9.ts, 7, 19), Decl(unusedTypeParameters9.ts, 10, 47), Decl(unusedTypeParameters9.ts, 11, 30), Decl(unusedTypeParameters9.ts, 12, 30), Decl(unusedTypeParameters9.ts, 13, 32))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 10, 13), Decl(unusedTypeParameters9.ts, 11, 13), Decl(unusedTypeParameters9.ts, 12, 13), Decl(unusedTypeParameters9.ts, 13, 13), Decl(unusedTypeParameters9.ts, 14, 13))
+>a : Symbol(C3.a, Decl(unusedTypeParameters9.ts, 10, 17))
+>c : Symbol(c, Decl(unusedTypeParameters9.ts, 10, 20))
+>p : Symbol(p, Decl(unusedTypeParameters9.ts, 10, 24))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 10, 13), Decl(unusedTypeParameters9.ts, 11, 13), Decl(unusedTypeParameters9.ts, 12, 13), Decl(unusedTypeParameters9.ts, 13, 13), Decl(unusedTypeParameters9.ts, 14, 13))
+
+interface C3<T> { b: string; }
+>C3 : Symbol(C3, Decl(unusedTypeParameters9.ts, 7, 19), Decl(unusedTypeParameters9.ts, 10, 47), Decl(unusedTypeParameters9.ts, 11, 30), Decl(unusedTypeParameters9.ts, 12, 30), Decl(unusedTypeParameters9.ts, 13, 32))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 10, 13), Decl(unusedTypeParameters9.ts, 11, 13), Decl(unusedTypeParameters9.ts, 12, 13), Decl(unusedTypeParameters9.ts, 13, 13), Decl(unusedTypeParameters9.ts, 14, 13))
+>b : Symbol(C3.b, Decl(unusedTypeParameters9.ts, 11, 17))
+
+interface C3<T> { c: number; }
+>C3 : Symbol(C3, Decl(unusedTypeParameters9.ts, 7, 19), Decl(unusedTypeParameters9.ts, 10, 47), Decl(unusedTypeParameters9.ts, 11, 30), Decl(unusedTypeParameters9.ts, 12, 30), Decl(unusedTypeParameters9.ts, 13, 32))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 10, 13), Decl(unusedTypeParameters9.ts, 11, 13), Decl(unusedTypeParameters9.ts, 12, 13), Decl(unusedTypeParameters9.ts, 13, 13), Decl(unusedTypeParameters9.ts, 14, 13))
+>c : Symbol(C3.c, Decl(unusedTypeParameters9.ts, 12, 17))
+
+interface C3<T> { d: boolean;  }
+>C3 : Symbol(C3, Decl(unusedTypeParameters9.ts, 7, 19), Decl(unusedTypeParameters9.ts, 10, 47), Decl(unusedTypeParameters9.ts, 11, 30), Decl(unusedTypeParameters9.ts, 12, 30), Decl(unusedTypeParameters9.ts, 13, 32))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 10, 13), Decl(unusedTypeParameters9.ts, 11, 13), Decl(unusedTypeParameters9.ts, 12, 13), Decl(unusedTypeParameters9.ts, 13, 13), Decl(unusedTypeParameters9.ts, 14, 13))
+>d : Symbol(C3.d, Decl(unusedTypeParameters9.ts, 13, 17))
+
+interface C3<T> { e: any; }
+>C3 : Symbol(C3, Decl(unusedTypeParameters9.ts, 7, 19), Decl(unusedTypeParameters9.ts, 10, 47), Decl(unusedTypeParameters9.ts, 11, 30), Decl(unusedTypeParameters9.ts, 12, 30), Decl(unusedTypeParameters9.ts, 13, 32))
+>T : Symbol(T, Decl(unusedTypeParameters9.ts, 10, 13), Decl(unusedTypeParameters9.ts, 11, 13), Decl(unusedTypeParameters9.ts, 12, 13), Decl(unusedTypeParameters9.ts, 13, 13), Decl(unusedTypeParameters9.ts, 14, 13))
+>e : Symbol(C3.e, Decl(unusedTypeParameters9.ts, 14, 17))
+
diff --git a/tests/baselines/reference/unusedTypeParameters9.types b/tests/baselines/reference/unusedTypeParameters9.types
new file mode 100644
index 00000000000..58a75e67297
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters9.types
@@ -0,0 +1,53 @@
+=== tests/cases/compiler/unusedTypeParameters9.ts ===
+
+// clas + interface
+class C1<T> { }
+>C1 : C1<T>
+>T : T
+
+interface C1<T> { a: T; }
+>C1 : C1<T>
+>T : T
+>a : T
+>T : T
+
+// interface + class
+class C2<T> { a: T; }
+>C2 : C2<T>
+>T : T
+>a : T
+>T : T
+
+interface C2<T> { }
+>C2 : C2<T>
+>T : T
+
+// interfaces
+interface C3<T> { a(c: (p: T) => void): void; }
+>C3 : C3<T>
+>T : T
+>a : (c: (p: T) => void) => void
+>c : (p: T) => void
+>p : T
+>T : T
+
+interface C3<T> { b: string; }
+>C3 : C3<T>
+>T : T
+>b : string
+
+interface C3<T> { c: number; }
+>C3 : C3<T>
+>T : T
+>c : number
+
+interface C3<T> { d: boolean;  }
+>C3 : C3<T>
+>T : T
+>d : boolean
+
+interface C3<T> { e: any; }
+>C3 : C3<T>
+>T : T
+>e : any
+
diff --git a/tests/cases/compiler/unusedTypeParameters6.ts b/tests/cases/compiler/unusedTypeParameters6.ts
new file mode 100644
index 00000000000..f445665f4ea
--- /dev/null
+++ b/tests/cases/compiler/unusedTypeParameters6.ts
@@ -0,0 +1,8 @@
+//@noUnusedLocals:true
+//@noUnusedParameters:true
+
+// @fileName: a.ts
+class C<T> { }
+
+// @fileName: b.ts
+interface C<T> { a: T; }
\ No newline at end of file
diff --git a/tests/cases/compiler/unusedTypeParameters7.ts b/tests/cases/compiler/unusedTypeParameters7.ts
new file mode 100644
index 00000000000..87b42d97650
--- /dev/null
+++ b/tests/cases/compiler/unusedTypeParameters7.ts
@@ -0,0 +1,8 @@
+//@noUnusedLocals:true
+//@noUnusedParameters:true
+
+// @fileName: a.ts
+class C<T> { a: T; }
+
+// @fileName: b.ts
+interface C<T> { }
\ No newline at end of file
diff --git a/tests/cases/compiler/unusedTypeParameters8.ts b/tests/cases/compiler/unusedTypeParameters8.ts
new file mode 100644
index 00000000000..4034ed04c72
--- /dev/null
+++ b/tests/cases/compiler/unusedTypeParameters8.ts
@@ -0,0 +1,8 @@
+//@noUnusedLocals:true
+//@noUnusedParameters:true
+
+// @fileName: a.ts
+class C<T> { }
+
+// @fileName: b.ts
+interface C<T> { }
\ No newline at end of file
diff --git a/tests/cases/compiler/unusedTypeParameters9.ts b/tests/cases/compiler/unusedTypeParameters9.ts
new file mode 100644
index 00000000000..48581d4ab2e
--- /dev/null
+++ b/tests/cases/compiler/unusedTypeParameters9.ts
@@ -0,0 +1,17 @@
+//@noUnusedLocals:true
+//@noUnusedParameters:true
+
+// clas + interface
+class C1<T> { }
+interface C1<T> { a: T; }
+
+// interface + class
+class C2<T> { a: T; }
+interface C2<T> { }
+
+// interfaces
+interface C3<T> { a(c: (p: T) => void): void; }
+interface C3<T> { b: string; }
+interface C3<T> { c: number; }
+interface C3<T> { d: boolean;  }
+interface C3<T> { e: any; }
\ No newline at end of file
diff --git a/tests/cases/conformance/decorators/class/decoratedClassExportsCommonJS1.ts b/tests/cases/conformance/decorators/class/decoratedClassExportsCommonJS1.ts
new file mode 100644
index 00000000000..e00adf3d63b
--- /dev/null
+++ b/tests/cases/conformance/decorators/class/decoratedClassExportsCommonJS1.ts
@@ -0,0 +1,13 @@
+// @target: es6
+// @experimentaldecorators: true
+// @emitDecoratorMetadata: true
+// @module: commonjs
+// @filename: a.ts
+
+declare function forwardRef(x: any): any;
+declare var Something: any;
+@Something({ v: () => Testing123 })
+export class Testing123 {
+    static prop0: string;
+    static prop1 = Testing123.prop0;
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/decorators/class/decoratedClassExportsCommonJS2.ts b/tests/cases/conformance/decorators/class/decoratedClassExportsCommonJS2.ts
new file mode 100644
index 00000000000..38f6ce9f27d
--- /dev/null
+++ b/tests/cases/conformance/decorators/class/decoratedClassExportsCommonJS2.ts
@@ -0,0 +1,10 @@
+// @target: es6
+// @experimentaldecorators: true
+// @emitDecoratorMetadata: true
+// @module: commonjs
+// @filename: a.ts
+
+declare function forwardRef(x: any): any;
+declare var Something: any;
+@Something({ v: () => Testing123 })
+export class Testing123 { }
\ No newline at end of file
diff --git a/tests/cases/conformance/decorators/class/decoratedClassExportsSystem1.ts b/tests/cases/conformance/decorators/class/decoratedClassExportsSystem1.ts
new file mode 100644
index 00000000000..1e2619ab89e
--- /dev/null
+++ b/tests/cases/conformance/decorators/class/decoratedClassExportsSystem1.ts
@@ -0,0 +1,13 @@
+// @target: es6
+// @experimentaldecorators: true
+// @emitDecoratorMetadata: true
+// @module: system
+// @filename: a.ts
+
+declare function forwardRef(x: any): any;
+declare var Something: any;
+@Something({ v: () => Testing123 })
+export class Testing123 {
+    static prop0: string;
+    static prop1 = Testing123.prop0;
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/decorators/class/decoratedClassExportsSystem2.ts b/tests/cases/conformance/decorators/class/decoratedClassExportsSystem2.ts
new file mode 100644
index 00000000000..bf7c9a0ca2d
--- /dev/null
+++ b/tests/cases/conformance/decorators/class/decoratedClassExportsSystem2.ts
@@ -0,0 +1,10 @@
+// @target: es6
+// @experimentaldecorators: true
+// @emitDecoratorMetadata: true
+// @module: system
+// @filename: a.ts
+
+declare function forwardRef(x: any): any;
+declare var Something: any;
+@Something({ v: () => Testing123 })
+export class Testing123 { }
\ No newline at end of file