Yii::$app->user->setReturnUrl(Yii::$app->request->referrer); //只需要添加这句话就可以了

public function actionLogin()
{
    if (!Yii::$app->user->isGuest) {
        return $this->goHome();
    }

    $model = new LoginForm();
    if ($model->load(Yii::$app->request->post()) && $model->login()) {
        return $this->goBack();
    } else {
        Yii::$app->user->setReturnUrl(Yii::$app->request->referrer);    //只需要添加这句话就可以了
        return $this->render('login', [
            'model' => $model,
        ]);
    }
}