Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
| 1 | <?php  | 
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| 19 | View Code Duplication | class InvalidRequestStackMiddlewareException extends InvalidDataTypeException  | 
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| 20 | { | 
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| 21 | |||
| 22 | /**  | 
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| 23 | * @param mixed $middleware_app_class  | 
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| 24 | * @param string $message  | 
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| 25 | * @param int $code  | 
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| 26 | * @param Exception $previous  | 
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| 27 | */  | 
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| 28 | public function __construct($middleware_app_class, $message = '', $code = 0, Exception $previous = null)  | 
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| 51 | }  | 
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| 52 |