There are some trailing characters in the link. But the tweet is > decltype(auto) f1(){int x = 0; return x;} > decltype(auto) f2(){int x = 0; return (x);} >

There are some trailing characters in the link. But the tweet is > decltype(auto) f1(){int x = 0; return x;} > decltype(auto) f2(){int x = 0; return (x);} > Latter, not former, returns reference to int.