c initialization algorithm

The algorithm for C initialization as described in the standard and implemented in gcc allow this.
struct X{
     int a,b,c;
};
int main()
{
     struct X x = {.a=1,2,3,.a=1, 2, 3};
}
https://godbolt.org/z/7naedbEM6
Basically, when a designed initializer is found the "cursor" goes to that member and the following members are initialized in order.
struct X{
     int a,b,c;
};
int main()
{
     struct X x = {.a=1,2,3,.a=1, 2, 3, .a=1, 4, 5};
}