## Why Does \'Fatal error: Class \'Shape\\Shape\' not found\' Occur When Using Namespaces and `use` Statements in PHP?

PHP Namespace and Use Statement Conundrum

In PHP, namespaces provide a logical structure for organizing classes, and the use statement enables aliases for shortening namespace references. However, a common pitfall arises when attempting to use both namespaces and the use statement effectively.

Let's delve into a scenario where you encounter an error: "Fatal error: Class 'ShapeShape' not found." This arises when you declare a namespace and then try to use the use Shape; statement.

Understanding the Use of Use

The use operator assigns an alias to a namespace, class, or interface. Its primary purpose is to shorten the reference to these entities. For example, the following code would create an alias Namespace for the MyFullNamespace namespace:

<code class="php">use My\Full\Namespace as Namespace;</code>

Now, you can refer to MyFullNamespaceFoo as NamespaceFoo.

Avoid Overlapping Namespaces and Use Statements

In your case, you have declared a namespace Shape in all three files (ShapeInterface.php, Shape.php, Circle.php), and the use Shape; statement attempts to use the Shape namespace. However, you have also included Shape.php and ShapeInterface.php in Circle.php. This overlap leads to the error.

Use Autoloading Instead

To avoid this issue, consider using autoloading instead of the use statement. Autoloading involves registering a function that checks for the existence of a class and loads it if not found. By registering an autoloader, you can eliminate the need for include statements and ensure that classes are loaded automatically upon instantiation.

One commonly used autoloader implementation follows the PSR-4 naming convention, which requires namespaces to map directly to the file system directory structure.

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