报告危险的数组初始化(如 $arr[] = value)。

This practice is discouraged because if $arr already contains some value (for example, a string from a request variable), then this value will stay in place and [] may actually stand for string access operator. It is always preferable to initialize a variable by direct assignment.

有关详细信息,请参阅 Creating/modifying with square bracket syntax (php.net)