a.ts(2,1): error TS2354: This syntax requires an imported helper but module 'tslib' cannot be found.


==== a.ts (1 errors) ====
    declare var dec: any;
    @dec export class A {
    ~~~~
!!! error TS2354: This syntax requires an imported helper but module 'tslib' cannot be found.
        #x: number = 1;
        async f() { this.#x = await this.#x; }
        g(u) { return #x in u; }
    }
    
    const o = { a: 1 };
    const y = { ...o };
    
==== tslib.d.ts (0 errors) ====
    export declare function __extends(d: Function, b: Function): void;
    export declare function __decorate(decorators: Function[], target: any, key?: string | symbol, desc?: any): any;
    export declare function __param(paramIndex: number, decorator: Function): Function;
    export declare function __metadata(metadataKey: any, metadataValue: any): Function;
    export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
    export declare function __classPrivateFieldGet(a: any, b: any, c: any, d: any): any;
    export declare function __classPrivateFieldSet(a: any, b: any, c: any, d: any, e: any): any;
    export declare function __classPrivateFieldIn(a: any, b: any): boolean;
    