Any language with function types and singletons. > Of course if it’s a special type with only a single elem with no relation to int, then it is again trivial.

Any language with function types and singletons. > Of course if it’s a special type with only a single elem with no relation to int, then it is again trivial. No, it isn't. "Trivial" in the context of Rice's theorem means either true of all Turing machines or false of all Turing machines.