JIT, optimization, data structures

Little Ive writes the following code in a dynamically typed programming language called Anus that features a GC and JIT.

var make_tuple = function(x,y){
  return function(i){
    return (i==0) ? x : y;
  }
}

Little Ive then calls the function make_tuple repeatedly with int32 in a tight loop, and sometimes also calls it with other arguments of other types as well.

How should Anus optimize this?  Discuss the situation and its complexities.