Corecursion.dfy(17,13): Error: cannot prove termination; try supplying a decreases clause (note that only functions without side effects can be called co-recursively) Execution trace: (0,0): anon0 (0,0): anon3_Else Corecursion.dfy(23,13): Error: cannot prove termination; try supplying a decreases clause (note that only functions without any ensures clause can be called co-recursively) Execution trace: (0,0): anon0 (0,0): anon3_Else Corecursion.dfy(58,5): Error: cannot prove termination; try supplying a decreases clause Execution trace: (0,0): anon0 (0,0): anon3_Else Corecursion.dfy(71,16): Error: cannot prove termination; try supplying a decreases clause (note that calls cannot be co-recursive in this context) Execution trace: (0,0): anon0 (0,0): anon5_Else Corecursion.dfy(93,15): 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) Execution trace: (0,0): anon0 (0,0): anon5_Else (0,0): anon6_Then Corecursion.dfy(103,15): 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) Execution trace: (0,0): anon0 (0,0): anon5_Else (0,0): anon6_Then Corecursion.dfy(148,13): Error: failure to decrease termination measure (note that a call can be co-recursive only if all intra-cluster calls are in non-destructive contexts) Execution trace: (0,0): anon0 (0,0): anon3_Else Corecursion.dfy(161,13): Error: failure to decrease termination measure (note that a call can be co-recursive only if all intra-cluster calls are in non-destructive contexts) Execution trace: (0,0): anon0 (0,0): anon3_Else Dafny program verifier finished with 20 verified, 8 errors