FnRef.dfy(17,45): Error: possible violation of function precondition
Execution trace:
    (0,0): anon0
    FnRef.dfy(15,12): anon5_Else
    (0,0): anon6_Then
FnRef.dfy(32,8): Error: possible violation of function precondition
Execution trace:
    (0,0): anon0
    FnRef.dfy(26,12): anon9_Else
    FnRef.dfy(28,8): anon10_Else
FnRef.dfy(46,12): Error: assertion violation
Execution trace:
    (0,0): anon0
    FnRef.dfy(43,12): anon7_Else
    (0,0): anon9_Then
FnRef.dfy(65,14): Error: assertion violation
Execution trace:
    (0,0): anon0
    FnRef.dfy(56,12): anon8_Else
    (0,0): anon10_Then

Dafny program verifier finished with 4 verified, 4 errors