Essentially, to get a nonterminating, program, your top level function needs to take a piece of codata to corecurse over to run indefinitely. Since you can't actually write a program that takes no arguments that produces an infinite piece of data, all programs must terminate.

>Since you can't actually write a program that takes no arguments that produces an infinite piece of data

Huh?

    inf = Cons 1 inf

Hm, you may be right. I though that was going to violate:

> Each recursive function call must be on a syntactic subcomponent of its formal parameter.

But it doesn't. But you can't actually use that to get a nonterminating program, because you can't recurse over it:

> Ordinary recursion is not legal over codata, because it might not terminate.