Clang is confused in a block with no return value by @Try{}

gistfile1.m

int main(int argc, const char * argv[])
{
    id (^iReturnStuff)() = ^id() {
        @try{} @finally{}
        //if you comment out line 4, Clang will not compile this.
        //if you leave it like this, Clang will compile and run this, even though
        //there's no value being returned.
        //is there something special in @try{} that turns off compiler errors?
    };
    return 0;
}

I am completely baffled by this. Can someone provide me with an explanation please? And I apologise in advance if it's something trivial that I should have known. Thanks!