直接上代码

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trait T1 {

public static $a=1;

public static $b= [];

public static function getC(){

echo 'class: ' . get_class() . "\n";

}

}

class a{

use T1;

}

class b extends a{

use T1;

public static function getHw(){

echo 'Hello';

}

}

b::getHw();

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运行以上代码，错误信息

Fatal error: a and T1 define the same property ($b) in the composition of b. However, the definition differs and is considered incompatible. Class was composed

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此时把

public static $b= [];改为public static $b= 1;非数组的其他类型正常运行。

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至于父类和子类都use T1,是为了让b::getC();取到的类名是b而不是a