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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| 15 | class Processor  | 
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| 16 | { | 
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| 17 | /**  | 
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| 18 | * @var array  | 
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| 19 | */  | 
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| 20 | private $handlers = [];  | 
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| 21 | |||
| 22 | /**  | 
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| 23 | * @var MapperInterface  | 
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| 24 | */  | 
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| 25 | private $mapper;  | 
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| 26 | |||
| 27 | /**  | 
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| 28 | * @var Invoker  | 
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| 29 | */  | 
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| 30 | private $invoker;  | 
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| 31 | |||
| 32 | /**  | 
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| 33 | * @var Interceptor  | 
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| 34 | */  | 
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| 35 | private $preProcess;  | 
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| 36 | |||
| 37 | /**  | 
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| 38 | * Processor constructor.  | 
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| 39 | */  | 
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| 40 | public function __construct()  | 
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| 46 | |||
| 47 | /**  | 
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| 48 | * @return Invoker  | 
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| 49 | */  | 
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| 50 | public function getInvoker(): Invoker  | 
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| 54 | |||
| 55 | /**  | 
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| 56 | * @param mixed $object  | 
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| 57 | */  | 
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| 58 | public function addHandler($object)  | 
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| 67 | |||
| 68 | /**  | 
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| 69 | * @param MapperInterface $mapper  | 
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| 70 | */  | 
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| 71 | public function setMapper(MapperInterface $mapper)  | 
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| 75 | |||
| 76 | /**  | 
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| 77 | * @param InvokeSpec $specifier  | 
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| 78 | *  | 
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| 79 | * @return ResultSpec  | 
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| 80 | */  | 
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| 81 | public function process(InvokeSpec $specifier): ResultSpec  | 
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| 100 | |||
| 101 | /**  | 
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| 102 | * @return Interceptor  | 
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| 103 | */  | 
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| 104 | public function onPreProcess(): Interceptor  | 
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| 108 | |||
| 109 | /**  | 
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| 110 | * @param AbstractInvoke $invoke  | 
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| 111 | *  | 
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| 112 | * @return AbstractInvoke  | 
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| 113 | */  | 
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| 114 | View Code Duplication | private function preProcess(AbstractInvoke $invoke): AbstractInvoke  | 
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| 124 | |||
| 125 | /**  | 
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| 126 | * @param Invoke\Invoke $unit  | 
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| 127 | *  | 
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| 128 | * @return Result\AbstractResult  | 
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| 129 | */  | 
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| 130 | private function handleCallUnit(Invoke\Invoke $unit): Result\AbstractResult  | 
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| 141 | |||
| 142 | /**  | 
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| 143 | * @param Invoke\Notification $unit  | 
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| 144 | *  | 
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| 145 | * @return Result\AbstractResult  | 
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| 146 | */  | 
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| 147 | private function handleNotificationUnit(Invoke\Notification $unit): Result\AbstractResult  | 
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| 158 | |||
| 159 | /**  | 
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| 160 | * @param Invoke\Error $unit  | 
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| 161 | *  | 
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| 162 | * @return Result\AbstractResult  | 
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| 163 | */  | 
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| 164 | private function handleErrorUnit(Invoke\Error $unit): Result\AbstractResult  | 
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| 168 | |||
| 169 | /**  | 
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| 170 | * @param string $requestedMethod  | 
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| 171 | *  | 
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| 172 | * @return array  | 
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| 173 | */  | 
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| 174 | private function getClassAndMethod(string $requestedMethod)  | 
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| 184 | }  | 
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| 185 | 
This check looks for parameters that are defined as one type in their type hint or doc comment but seem to be used as a narrower type, i.e an implementation of an interface or a subclass.
Consider changing the type of the parameter or doing an instanceof check before assuming your parameter is of the expected type.