struct S {
	int i;
	int j;
};

S sa {1, 2};
S sb {sa};

The effects of list initialization of an object of type T are: If T is an aggregate class and the initializer list has a single element of the same or derived type (possibly cv-qualified), the object is initialized from that element (by copy-initialization for copy-list-initialization, or by direct-initialization for direct-list-initialization).