The use use of '=' here scares me:

   function add2(x: Int, y: Int): Int {
       return x + y;
   }
   
   add2(2, 3)     //5
   add2(x=2, y=3) //5
   add2(y=2, 5)   //7

The language already supports '=' operator for assignment of variables in the current scope, so should you use the same operator for denoting value assignment formal parameters in a function call? This can lead to a lot of confusion between variables in the scope and formal parameter names in a function that is called from the current scope.