protected override ProofOutcome ValidateInternalSpecific(IFactQuery <BoxedExpression, Variable> query, ContractInferenceManager inferenceManager, IOutputResults output)
{
// Check if expForIndex >= 0
return(query.IsGreaterEqualToZero(this.PC, index));
#if false
// Try to use weakest preconditions
if (result == ProofOutcome.Top)
{
if (CanAssumeLowerBoundPrecondition(output, this.index))
{
result = ProofOutcome.True;
}
else
{
// if we have lb <= i, then we can suggest 0 <= lb
//
foreach (Variable lb in query.LowerBounds(this.PC, index, false))
{
BoxedExpression lbbox = BoxedExpression.Var(lb);
if (CanAssumeLowerBoundPrecondition(output, lbbox))
{
result = ProofOutcome.True;
}
}
}
}
return(result);
#endif
}
protected override ProofOutcome ValidateInternalSpecific(IFactQuery <BoxedExpression, Variable> query, ContractInferenceManager inferenceManager, IOutputResults output)
{
// First, we check if arg != MinValue
object value;
if (!this.DecoderForMetaData.TryGetMinValueForType(this.typeOfArg, out value))
{
return(ProofOutcome.Top);
}
var condition = this.Condition;
if (condition != null) // this.Condition may return null
{
var result = query.IsTrue(this.PC, condition);
if (result != ProofOutcome.Top)
{
return(result);
}
}
// We check a sufficient condition: if arg is >= 0, then it is not the negation of a negative "extreme"
var greaterThanZero = query.IsGreaterEqualToZero(this.PC, this.arg);
return((greaterThanZero == ProofOutcome.True || greaterThanZero == ProofOutcome.Bottom)
? greaterThanZero : ProofOutcome.Top);
}
protected override ProofOutcome ValidateInternalSpecific(IFactQuery <BoxedExpression, Variable> query, ContractInferenceManager inferenceManager, IOutputResults output)
{
return(query.IsGreaterEqualToZero(this.PC, this.size));
}