EmptyList.bpl(52,9): Warning: type parameter a is ambiguous, instantiating to List int
EmptyList.bpl(34,3): Error BP5001: This assertion might not hold.
Execution trace:
    EmptyList.bpl(32,5): anon0
EmptyList.bpl(48,3): Error BP5001: This assertion might not hold.
Execution trace:
    EmptyList.bpl(32,5): anon0
EmptyList.bpl(52,3): Error BP5001: This assertion might not hold.
Execution trace:
    EmptyList.bpl(52,3): anon0

Boogie program verifier finished with 0 verified, 3 errors