Decorator emits undefined default_1

[Igorbek]

TypeScript Version: 2.2.1

tsconfig.json

{
    "compilerOptions": {
        "experimentalDecorators": true,
        "module": "es2015",
        "target": "es2015"
    }
}

Code

declare const decorator: PropertyDecorator;

export default class {
    @decorator a = 1;
}

Expected emit:

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;
};
const default_1 = class {
    constructor() {
        this.a = 1;
    }
}
__decorate([
    decorator
], default_1.prototype, "a", void 0);

export default default_1;

Actual emit:

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;
};
export default class {
    constructor() {
        this.a = 1;
    }
}
__decorate([
    decorator
], default_1.prototype, "a", void 0);

As a result, a run-time error thrown 'default_1 is not defined'