## Why is this an issue?

Instances of classes that do not derive from the "Throwable" interface cannot be used in a PHP "throw" statement.

Many built-in exceptions such as "Exception" and the SPL exception classes do implement the "Throwable" interface and can be extended when creating custom exceptions.

This rule raises an issue when an instance of a class that does not implement the "Throwable" interface is used in a "throw" statement .

### Noncompliant code example

    class NoThrowable {}

    throw new NoThrowable(); // Noncompliant

### Compliant solution

    <?php

    class SomeThrowable implements Throwable {
        // Implementation of the Throwable methods
    }

    throw new SomeThrowable(); // Compliant

    class SomeCustomException extends Exception {}

    throw new SomeCustomException(); // Compliant{code}