user导出，auth导入，这样auth服务能用user服务；auth控制器使用auth服务

src/modules/auth/auth.controller.ts

@@ -1,4 +1,9 @@
 import { Controller } from '@nestjs/common';
+import { AuthService } from './auth.service';
 
 @Controller('auth')
-export class AuthController {}
+export class AuthController {
+    constructor(
+        private readonly authService: AuthService,
+    ) { }
+}

src/modules/auth/auth.module.ts

@@ -1,8 +1,12 @@
 import { Module } from '@nestjs/common';
 import { AuthController } from './auth.controller';
 import { AuthService } from './auth.service';
+import { UserModule } from '../user/user.module';
 
 @Module({
+  imports: [
+    UserModule,
+  ],
   controllers: [AuthController],
   providers: [AuthService]
 })

src/modules/auth/auth.service.ts

@@ -1,4 +1,9 @@
 import { Injectable } from '@nestjs/common';
+import { UserService } from '../user/user.service';
 
 @Injectable()
-export class AuthService {}
+export class AuthService {
+    constructor(
+        private readonly userService: UserService,
+    ) {}
+}

src/modules/user/user.module.ts

@@ -9,6 +9,7 @@ import { User } from './user.entity';
     TypeOrmModule.forFeature([User]),
   ],
   controllers: [UserController],
-  providers: [UserService]
+  providers: [UserService],
+  exports: [UserService]
 })
 export class UserModule {}