text.dfy(9,0): Error: a postcondition could not be proved on this return path
text.dfy(8,12): Related location: this is the postcondition that could not be proved
text.dfy(11,0): Error: out-parameter 'b', which is subject to definite-assignment rules, might be uninitialized at this return point

Dafny program verifier finished with 1 verified, 2 errors
