[class.access.base] Are friends defined in-class "in" the class for purposes of access control? CWG1699

A member m is accessible at the point R when named in class N if

• m as a member of N is private, and R occurs in a direct member or friend of class N

Please see this example:

class A{
    int v;
    friend class B;
};
class B{
    friend void fun(A& t){
        t.v = 0;  // R occurs here
    }
};

Clang accepts this code while GCC rejects it. According to the above rule, It appears to me that R indeed occurs in the direct friend of class A, where A is the naming class and the direct friend of A is class B. So, Is that the meaning of "in" interpreted by Clang be the original intent of the standard? I suppose it's not true. Meanwhile, the example given in [class.friend#10] is a bit different from this example since R does not occur in the direct friend of the granting friendship class.

There's no rule elsewhere in the standard that restricts the border-line that R occurs in a friend class would be. Conversely, there's still no rule in the standard guarantees that this example is definitely ill-formed, in the same way as these rules:

A member of a class can also access all the members to which the class has access. A local class of a member function may access the same members that the member function itself may access.

Declaring a class to be a friend implies that private and protected members of the class granting friendship can be named in the base-specifiers and member declarations of the befriended class.

Since a friend declaration of a class does not introduce a new member for that class, fun is not a member of class B, The above rules are not suitable here.
So, I think this case is in an underspecified situation, which might be the reason why GCC and Clang have quite different interpretations for this example. I mean the standard does not explicitly say "no" to the overread of the wording "in" of Clang.

Start with [class.access.base] and [class.friend#10], then compare the linked Compiler Explorer example under GCC and Clang. Determine whether “in a direct member or friend” includes the friend definition shown and record the intended resolution for CWG1699.