这是故意不可能的，因为在对标量类型提示进行了长时间讨论之后采​​用的实现是这样的: https://wiki.php.net/rfc/scalar_type_hints_v5

This is deliberately not possible, because the implementation adopted after an extremely long discussion of scalar type hints was this one: https://wiki.php.net/rfc/scalar_type_hints_v5

它显式地给出了选择如何对任何函数的调用者(而不是其作者)检查标量类型的选择，以便:

It explicitly gives the choice of how scalar types are checked to the caller of any function, not its author, so that:

• 如果您编写的具有标量类型提示的库，则即使没有以严格模式编写的代码(而是强制使用类型的代码)调用了函数，也可以保证函数具有请求的参数类型
• 如果您编写一个库并希望使用传统的弱类型输入，您仍然可以使用带有类型提示的库(因为它们不会强迫您执行严格的类型检查)
• 相反，如果您编写一个库并希望对调用的函数进行严格键入 ，则不必要求库的用户也启用严格键入
• 内置函数的功能与用户定义的功能相同，并且默认情况下，现有代码运行的方式相同
• 如果您启用严格输入，则需要更改代码以正确处理它

• if you write a library with scalar type hints, your functions are guaranteed the parameter types requested, even if called by code not written in strict mode (the types are coerced instead)
• if you write a library and want traditional weak typing, you can still make use of libraries that use type hints (because they don't force you to perform strict type checking)
• contrarily, if you write a library and want strict typing for functions that you call, you don't have to require that users of your library also enable strict typing
• built-in functions work the same way as user-defined ones, and existing code runs the same by default
• if you turn on strict typing, you need to change your code to handle it correctly anyway

因此，由您决定告诉PHP哪些文件已编写为使用严格类型模式，哪些文件没有使用严格类型模式.而执行此操作的方法是使用declare语句.

It's therefore up to you to tell PHP which files have been written to use strict type mode, and which haven't; and the way to do this is using the declare statement.