**一.ReflectionParameter::isCallable弃用** 1.代码实例 ``` function foo(callable $arr) { } $functionReflection = new ReflectionFunction('foo'); $parameters = $functionReflection->getParameters(); $eParameter = $parameters[0]; var_dump($eParameter->isCallable()); ``` 2.低版本 ``` bool(true) ``` 3.新版本 ``` Deprecated: Method ReflectionParameter::isCallable() is deprecated ```