Estou tentando criar o HTTP Interceptor no Angular 4, mas estou tendo algum erro estranho. A seguir está o meu erro:

Argument of type 'Observable<Response>' is not assignable to parameter of type 'Observable<Response>'.

A seguir está o meu código:

import { Injectable } from '@angular/core';
import { Http, ConnectionBackend, RequestOptions, RequestOptionsArgs } from '@angular/http';
import { Router } from '@angular/router';
import { Observable } from 'rxjs/Observable';
import * as _ from 'lodash';

@Injectable()
export class HttpInterceptor extends Http {

    constructor(backend: ConnectionBackend, defaultOptions: RequestOptions, private _router: Router) {
        super(backend, defaultOptions);
    }

    request(url: string | Request, options?: RequestOptionsArgs): Observable<Response> {
        return this.intercept(super.request(url, options)); // Here is the error
    }

    get(url: string, options?: RequestOptionsArgs): Observable<Response> {
        return this.intercept(super.get(url, options)); // Here is the error
    }

    post(url: string, body: string, options?: RequestOptionsArgs): Observable<Response> {
        return this.intercept(super.post(url, body, this.getRequestOptionArgs(options))); // Here is the error
    }

    put(url: string, body: string, options?: RequestOptionsArgs): Observable<Response> {
        return this.intercept(super.put(url, body, this.getRequestOptionArgs(options))); // Here is the error
    }

    delete(url: string, options?: RequestOptionsArgs): Observable<Response> {
        return this.intercept(super.delete(url, options)); // Here is the error
    }

    getRequestOptionArgs(options?: RequestOptionsArgs): RequestOptionsArgs {
        if (options == null) {
            options = new RequestOptions();
        }
        if (options.headers == null) {
            options.headers = new Headers(); // Here is the error
        }
        options.headers.append('Content-Type', 'application/json');
        return options;
    }

    intercept(observable: Observable<Response>): Observable<Response> {
        return observable.catch((err, source) => {
            if (err.status == 401 && !_.endsWith(err.url, 'api/auth/login')) {
                this._router.navigate(['/login']);
                return Observable.empty();
            } else {
                return Observable.throw(err);
            }
        });

    }

}

Alguém sabe o que está acontecendo de errado aqui? Tentei depurar por 3 horas, mas não consegui encontrar nenhuma pista.

Editar:

Eu também tentei remover tudo e escrevi um código como este:

request(url: string | Request, options?: RequestOptionsArgs): Observable<Response> {
    return super.request(url, options);
}

Mas ainda está dando o mesmo erro:

Argument of type 'string | Request' is not assignable to parameter of type 'string | Request'. Type 'Request' is not assignable to type 'string | Request'.