The elements of an aggregate are:

• [...]
• for a class, the direct base classes in declaration order, followed by the direct non-static data members ([class.mem]) that are not members of an anonymous union, in declaration order.

static union {
   int c;
};

The member c is an element of the anonymous union, I believe. Presumably, the intent of [dcl.init.aggr] p2 is to exclude the member of an anonymous union member of a class of which that member is a direct member. Should we say

for a class, the direct base classes in declaration order, followed by the direct non-static data members ([class.mem]) that are not members of an anonymous union member, in declaration order.

It could make that rule admit that a member of an anonymous union is an element of the anonymous union.