public override IEnumerable <ProgramState> TrySetConstraint(SymbolicValueConstraint constraint, ProgramState programState)
{
var boolConstraint = constraint as BoolConstraint;
if (boolConstraint == null)
{
return(new[] { programState });
}
SymbolicValueConstraints oldConstraints;
BoolConstraint oldBoolConstraint = null;
if (TryGetConstraints(programState, out oldConstraints))
{
oldBoolConstraint = oldConstraints.GetConstraintOrDefault <BoolConstraint>();
}
if (oldBoolConstraint != null /* could also be ObjectConstraint.NotNull, which can be overridden */ &&
oldBoolConstraint != boolConstraint)
{
return(Enumerable.Empty <ProgramState>());
}
SymbolicValueConstraints leftConstraints;
var leftHasConstraint = LeftOperand.TryGetConstraints(programState, out leftConstraints);
SymbolicValueConstraints rightConstraints;
var rightHasConstraint = RightOperand.TryGetConstraints(programState, out rightConstraints);
var relationship = GetRelationship(boolConstraint);
var newProgramState = programState.TrySetRelationship(relationship);
if (newProgramState == null)
{
return(Enumerable.Empty <ProgramState>());
}
if (!rightHasConstraint && !leftHasConstraint)
{
return(new[] { newProgramState });
}
return(SetConstraint(boolConstraint, leftConstraints, rightConstraints, newProgramState));
}