How does it work?

What does this mean:

  let hmm:t5034175 = ([] == {});
  let mmh:t5034194 = ({} == []);
  var r:string = null;
  if (hmm) {
    r = hmm;
  } else {
    r = mmh;
  }

  r = hmm + mmh;

            :(possible candidates all failed:
                ) -> possible candidates all failed:
  function f                                        (t) { return t + t; }
  
         :possible candidates all failed:
  var rrr                                = f(r);

?