## Why is this an issue?

Repeating an exception class in a single `catch` clause will not fail but it is not what the developer intended. Either the class is not the one which should be caught, or this is dead code.

Having a subclass and a parent class in the same `catch` clause is also useless. It is enough to keep only the parent class.

This rule raises an issue when an exception class is duplicated in a `catch` clause, or when an exception class has a parent class in the same `catch` clause.

### Noncompliant code example

    try {
        throw new CustomException();
    } catch(CustomException | Exception $e) { // Noncompliant. CustomException inherits from Exception
        echo $e->message();
    }

    try {
        throw new CustomException();
    } catch(Exception | Exception $e) { // Noncompliant.
        echo $e->message();
    }

### Compliant solution

    try {
        throw new CustomException();
    } catch(Exception $e) {
        echo $e->message();
    }

    try {
        throw new CustomException();
    } catch(CustomException $e) {
        echo $e->getCustomMessage();
    } catch(Exception $e) {
        echo $e->message();
    }

## Resources

- RFC - Catching Multiple Exception Types