CodeExpr1.bpl(46,5): Error BP5003: A postcondition might not hold on this return path.
CodeExpr1.bpl(42,3): Related location: This is the postcondition that might not hold.
Execution trace:
    CodeExpr1.bpl(44,3): start
CodeExpr1.bpl(54,5): Error BP5001: This assertion might not hold.
Execution trace:
    CodeExpr1.bpl(51,3): start
CodeExpr1.bpl(68,5): Error BP5001: This assertion might not hold.
Execution trace:
    CodeExpr1.bpl(59,3): start

Boogie program verifier finished with 3 verified, 3 errors