Corecursion.dfy(17,12): Error: cannot prove termination; try supplying a decreases clause (note that only functions without side effects can be called co-recursively)
Corecursion.dfy(23,12): Error: cannot prove termination; try supplying a decreases clause (note that only functions without any ensures clause can be called co-recursively)
Corecursion.dfy(58,4): Error: cannot prove termination; try supplying a decreases clause
Corecursion.dfy(71,15): Error: cannot prove termination; try supplying a decreases clause (note that calls cannot be co-recursive in this context)
Corecursion.dfy(93,14): Error: cannot prove termination; try supplying a decreases clause (note that a call can be co-recursive only if all intra-cluster calls are in non-destructive contexts)
Corecursion.dfy(103,14): Error: cannot prove termination; try supplying a decreases clause (note that a call can be co-recursive only if all intra-cluster calls are in non-destructive contexts)
Corecursion.dfy(148,12): Error: decreases clause might not decrease (note that a call can be co-recursive only if all intra-cluster calls are in non-destructive contexts)
Corecursion.dfy(161,12): Error: decreases clause might not decrease (note that a call can be co-recursive only if all intra-cluster calls are in non-destructive contexts)

Dafny program verifier finished with 14 verified, 8 errors
