> We have lots of formally verified programs that show useful work can be done here
Yes, if you start writing your program with the explicit intent of making such proofs possible, then it can be done. What Rice's theorem says is that you can't expect to be able to do so when given an arbitrary program, not that it's always impossible.
Yes, if you start writing your program with the explicit intent of making such proofs possible, then it can be done. What Rice's theorem says is that you can't expect to be able to do so when given an arbitrary program, not that it's always impossible.