The definition of pointer-interconvertible (https://eel.is/c++draft/basic.compound#6) states that:

如果两个对象是指针互转的，那么它们具有相同的地址，可以通过一个 reinterpret_cast（[expr.reinterpret.cast]）从指向一个对象的指针得到指向另一个对象的指针。

Yet in reinterpret_cast section https://eel.is/c++draft/expr.reinterpret.cast, there is no mention of it, while it is mentioned for static_cast (https://eel.is/c++draft/expr.static.cast#12):

A prvalue of type “pointer to cv1 void” can be converted to a prvalue of type “pointer to cv2 T”, where T is an object type and cv2 is the same cv-qualification as, or greater cv-qualification than, cv1. If the original pointer value represents the address A of a byte in memory and A does not satisfy the alignment requirement of T, then the resulting pointer value ([basic.compound]) is unspecified. Otherwise, if the original pointer value points to an object a, and there is an object b of type similar to T that is pointer-interconvertible with a, the result is a pointer to b. Otherwise, the pointer value is unchanged by the conversion.

在 reinterpret_cast 小节 https://eel.is/c++draft/expr.reinterpret.cast 中，没有提及这一点；而在 static_cast (https://eel.is/c++draft/expr.static.cast#12) 中有提及：

类型为“cv1 void指针”的prvalue可以转换为类型为“cv2 T指针”的prvalue，其中T 是对象类型，cv2的 cv-限定与cv1相同，或比cv1的 cv-限定更高。若原指针值表示内存中某字节地址A，且A 不满足T 的对齐要求，则结果指针值 ([basic.compound]) 未指定。否则，若原指针值指向对象a，且存在类型与T 相似并且与a 互相可指针互转的对象b，则结果是指向b 的指针。否则，指针值在转换中保持不变。

IMHO, it is more meaningful to say that static_cast is allowed for getting a pointer to a pointer-interconvertible type as it basically means that they are pointing to the same object, potentially nested differently.

在我看来，说 static_cast 允许获取一个指向指针互转类型的指针更有意义，因为这基本上意味着它们指向同一个对象，尽管嵌套形式可能不同。

Besides, the fact that using static_cast in this context implies that reinterpret _cast is also valid, through https://eel.is/c++draft/expr.reinterpret.cast#7:

the result is static_cast(static_cast(v))

此外，在这种上下文中使用 static_cast 还意味着 reinterpret _cast 也是有效的，参见 https://eel.is/c++draft/expr.reinterpret.cast#7：

结果是static_cast(static_cast(v))

Is it a typo in the standard or is there a rationale to mention reinterpret_cast instead of static_cast in pointer-interconvertible definition?

这是标准中的笔误吗，还是在指针互转的定义中提及 reinterpret_cast 而不是 static_cast 是有其道理的？

解决方案

IMHO, it is more meaningful to say that static_cast is allowed for getting a pointer to a pointer-interconvertible type

在我看来，说 static_cast 可以用来获取一个指向指针互转类型的指针，更有意义。

It is actually not the case

其实并非如此

struct S
{
    int i;
    int j;
};

static_assert(std::is_pointer_interconvertible_with_class(&S::i));
static_assert(!std::is_pointer_interconvertible_with_class(&S::j));

int main()
{
    S s{42, 51};
    [[maybe_unused]]int* ok = reinterpret_cast<int*>(&s); // Compiles
    [[maybe_unused]]int* ko = static_cast<int*>(&s); // Fails
}

Demo