As of http://digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=150299

If we disable this(this) in a struct, the opAssign member function should be used if it exists. Here is a sample code :

module fail2;

struct Fail {
	@disable
	this(this);
	
	ref Fail opAssign(ref const Fail t) {
		return this;
	}
}

int main(string[] argv) {
	Fail a;
	Fail b = a; // Error: struct fail2.Fail is not copyable because it is annotated with @disable
	
	return 0;
}