Well, the thing is, anything would be better than what we have currently. I know that in general the problem is undecidable. But we don't need to solve the ent

Well, the thing is, anything would be better than what we have currently. I know that in general the problem is undecidable. But we don't need to solve the entire problem to solve a large chunk of practical cases. Even a simple runtime cast (with check) / asserting cast (a cast with an assertion that would be triggered at compile time if the compiler can find a valid counterexample, otherwise unchecked) combination would be miles above what we have now in most strongly typed languages.