diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 4fde6a321a4..b9f33abe6c8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -17434,6 +17434,7 @@ namespace ts {
             checkGrammarDecorators(node) || checkGrammarModifiers(node);
 
             checkTypeNameIsReserved(node.name, Diagnostics.Type_alias_name_cannot_be_0);
+            checkTypeParameters(node.typeParameters);
             checkSourceElement(node.type);
         }
 
diff --git a/tests/baselines/reference/nounusedTypeParameterConstraint.js b/tests/baselines/reference/nounusedTypeParameterConstraint.js
new file mode 100644
index 00000000000..aa403187f7a
--- /dev/null
+++ b/tests/baselines/reference/nounusedTypeParameterConstraint.js
@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/nounusedTypeParameterConstraint.ts] ////
+
+//// [bar.ts]
+
+export interface IEventSourcedEntity { }
+
+//// [test.ts]
+import { IEventSourcedEntity } from "./bar";
+export type DomainEntityConstructor<TEntity extends IEventSourcedEntity> = { new(): TEntity; };
+
+//// [bar.js]
+"use strict";
+//// [test.js]
+"use strict";
diff --git a/tests/baselines/reference/nounusedTypeParameterConstraint.symbols b/tests/baselines/reference/nounusedTypeParameterConstraint.symbols
new file mode 100644
index 00000000000..40364460f50
--- /dev/null
+++ b/tests/baselines/reference/nounusedTypeParameterConstraint.symbols
@@ -0,0 +1,15 @@
+=== tests/cases/compiler/bar.ts ===
+
+export interface IEventSourcedEntity { }
+>IEventSourcedEntity : Symbol(IEventSourcedEntity, Decl(bar.ts, 0, 0))
+
+=== tests/cases/compiler/test.ts ===
+import { IEventSourcedEntity } from "./bar";
+>IEventSourcedEntity : Symbol(IEventSourcedEntity, Decl(test.ts, 0, 8))
+
+export type DomainEntityConstructor<TEntity extends IEventSourcedEntity> = { new(): TEntity; };
+>DomainEntityConstructor : Symbol(DomainEntityConstructor, Decl(test.ts, 0, 44))
+>TEntity : Symbol(TEntity, Decl(test.ts, 1, 36))
+>IEventSourcedEntity : Symbol(IEventSourcedEntity, Decl(test.ts, 0, 8))
+>TEntity : Symbol(TEntity, Decl(test.ts, 1, 36))
+
diff --git a/tests/baselines/reference/nounusedTypeParameterConstraint.types b/tests/baselines/reference/nounusedTypeParameterConstraint.types
new file mode 100644
index 00000000000..8f2de483d26
--- /dev/null
+++ b/tests/baselines/reference/nounusedTypeParameterConstraint.types
@@ -0,0 +1,15 @@
+=== tests/cases/compiler/bar.ts ===
+
+export interface IEventSourcedEntity { }
+>IEventSourcedEntity : IEventSourcedEntity
+
+=== tests/cases/compiler/test.ts ===
+import { IEventSourcedEntity } from "./bar";
+>IEventSourcedEntity : any
+
+export type DomainEntityConstructor<TEntity extends IEventSourcedEntity> = { new(): TEntity; };
+>DomainEntityConstructor : new () => TEntity
+>TEntity : TEntity
+>IEventSourcedEntity : IEventSourcedEntity
+>TEntity : TEntity
+
diff --git a/tests/baselines/reference/typeAliasDeclarationEmit.errors.txt b/tests/baselines/reference/typeAliasDeclarationEmit.errors.txt
new file mode 100644
index 00000000000..2fd71844dc4
--- /dev/null
+++ b/tests/baselines/reference/typeAliasDeclarationEmit.errors.txt
@@ -0,0 +1,10 @@
+tests/cases/compiler/typeAliasDeclarationEmit.ts(4,37): error TS2314: Generic type 'callback' requires 1 type argument(s).
+
+
+==== tests/cases/compiler/typeAliasDeclarationEmit.ts (1 errors) ====
+    
+    export type callback<T> = () => T;
+    
+    export type CallbackArray<T extends callback> = () => T;
+                                        ~~~~~~~~
+!!! error TS2314: Generic type 'callback' requires 1 type argument(s).
\ No newline at end of file
diff --git a/tests/cases/compiler/nounusedTypeParameterConstraint.ts b/tests/cases/compiler/nounusedTypeParameterConstraint.ts
new file mode 100644
index 00000000000..d2c3a1677ee
--- /dev/null
+++ b/tests/cases/compiler/nounusedTypeParameterConstraint.ts
@@ -0,0 +1,8 @@
+//@noUnusedLocals:true
+
+//@filename: bar.ts
+export interface IEventSourcedEntity { }
+
+//@filename: test.ts
+import { IEventSourcedEntity } from "./bar";
+export type DomainEntityConstructor<TEntity extends IEventSourcedEntity> = { new(): TEntity; };
\ No newline at end of file
diff --git a/tests/webTestServer.ts b/tests/webTestServer.ts
index 97027dfdd49..3d23ef3e961 100644
--- a/tests/webTestServer.ts
+++ b/tests/webTestServer.ts
@@ -128,7 +128,7 @@ function dir(dirPath: string, spec?: string, options?: any) {
 // fs.rmdirSync won't delete directories with files in it
 function deleteFolderRecursive(dirPath: string) {
     if (fs.existsSync(dirPath)) {
-        fs.readdirSync(dirPath).forEach((file, index) => {
+        fs.readdirSync(dirPath).forEach((file) => {
             const curPath = path.join(path, file);
             if (fs.statSync(curPath).isDirectory()) { // recurse
                 deleteFolderRecursive(curPath);
@@ -141,7 +141,7 @@ function deleteFolderRecursive(dirPath: string) {
     }
 };
 
-function writeFile(path: string, data: any, opts: { recursive: boolean }) {
+function writeFile(path: string, data: any) {
     ensureDirectoriesExist(getDirectoryPath(path));
     fs.writeFileSync(path, data);
 }
@@ -208,7 +208,7 @@ enum RequestType {
     Unknown
 }
 
-function getRequestOperation(req: http.ServerRequest, filename: string) {
+function getRequestOperation(req: http.ServerRequest) {
     if (req.method === "GET" && req.url.indexOf("?") === -1) {
         if (req.url.indexOf(".") !== -1) return RequestType.GetFile;
         else return RequestType.GetDir;
@@ -258,7 +258,7 @@ function handleRequestOperation(req: http.ServerRequest, res: http.ServerRespons
             break;
         case RequestType.WriteFile:
             processPost(req, res, (data) => {
-                writeFile(reqPath, data, { recursive: true });
+                writeFile(reqPath, data);
             });
             send(ResponseCode.Success, res, undefined);
             break;
@@ -306,7 +306,7 @@ http.createServer((req: http.ServerRequest, res: http.ServerResponse) => {
     log(`${req.method} ${req.url}`);
     const uri = url.parse(req.url).pathname;
     const reqPath = path.join(process.cwd(), uri);
-    const operation = getRequestOperation(req, reqPath);
+    const operation = getRequestOperation(req);
     handleRequestOperation(req, res, operation, reqPath);
 }).listen(port);