What is the difference between referencing a class with or without a leading backslash in PHP?

When referencing a class without a leading backslash in PHP, the interpreter will look for the class relative to the current namespace. If the class is not found in the current namespace, PHP will search for the class in the global namespace. On the other hand, when referencing a class with a leading backslash, PHP will always search for the class in the global namespace, regardless of the current namespace. To ensure that the correct class is referenced, always use a leading backslash when referencing a class in PHP.

// Referencing a class without a leading backslash
use App\Models\User; // Will look for User class in the current namespace first, then in the global namespace

// Referencing a class with a leading backslash
use \App\Models\User; // Will always look for User class in the global namespace