Why Repository interface bind to service container - laravel

Question

We need to use Repository in laravel application. We want create Two important things one is Repository Interface and another one Repository class
My doubt is Why Repository interface and Repository class register to service provider
I removed repository interface and class from service provider
show below error
"Target [App\Repository\UserInterface] is not instantiable while building "
<?php
namespace App\Repository\user;
use Illuminate\Support\ServiceProvider;
class UserRepoServiceProvide extends ServiceProvider
{
/**
* Bootstrap the application services.
*
* #return void
*/
public function boot()
{
}
/**
* Register the application services.
*
* #return void
*/
public function register()
{
// $this->app->bind('App\Repository\UserInterface', 'App\Repository\user\UserRepository');
}
}

Answer 1

An Interface class is just a definition of methods (without their body), hence is not instantiable. That means you can't do a new App\Repository\UserInterface().
Somewhere in your code you have a method (or maybe a constructor?) that takes a UserInterface dependency, something like
public function myMethod(UserInterface $repository) {
...
}
// or
public function __construct(UserInterface $repository) {
...
}
If you remove the binding, Laravel will try to instantiate an UserInterface and that will result in the error you get.
When working with interfaces you have always to bind() them with concrete classes.
I have a question, why did you remove the binding from ServiceProvider?