public override object VisitBinaryOperatorExpression(BinaryOperatorExpression binaryOperatorExpression, object data)
{
// lifted operators can't be transformed
if (binaryOperatorExpression.Annotation <LiftedOperator>() != null)
{
return(base.VisitBinaryOperatorExpression(binaryOperatorExpression, data));
}
BinaryOperatorType op = binaryOperatorExpression.Operator;
bool?rightOperand = null;
if (binaryOperatorExpression.Right is PrimitiveExpression)
{
rightOperand = ((PrimitiveExpression)binaryOperatorExpression.Right).Value as bool?;
}
if (op == BinaryOperatorType.Equality && rightOperand == true || op == BinaryOperatorType.InEquality && rightOperand == false)
{
// 'b == true' or 'b != false' is useless
var ilRanges = binaryOperatorExpression.GetAllRecursiveILRanges();
binaryOperatorExpression.Left.AcceptVisitor(this, data);
binaryOperatorExpression.ReplaceWith(binaryOperatorExpression.Left.WithAnnotation(ilRanges));
return(null);
}
else if (op == BinaryOperatorType.Equality && rightOperand == false || op == BinaryOperatorType.InEquality && rightOperand == true)
{
// 'b == false' or 'b != true' is a negation:
Expression left = binaryOperatorExpression.Left;
left.Remove();
var ilRanges = binaryOperatorExpression.GetAllRecursiveILRanges();
UnaryOperatorExpression uoe = new UnaryOperatorExpression(UnaryOperatorType.Not, left);
binaryOperatorExpression.ReplaceWith(uoe);
uoe.AddAnnotation(ilRanges);
return(uoe.AcceptVisitor(this, data));
}
else
{
bool negate = false;
Match m = asCastIsNotNullPattern.Match(binaryOperatorExpression);
if (!m.Success)
{
m = asCastIsNullPattern.Match(binaryOperatorExpression);
negate = true;
}
if (m.Success)
{
Expression expr = m.Get <Expression>("expr").Single().Detach().IsType(m.Get <AstType>("type").Single().Detach());
if (negate)
{
expr = new UnaryOperatorExpression(UnaryOperatorType.Not, expr);
}
binaryOperatorExpression.ReplaceWith(expr);
expr.AddAnnotation(binaryOperatorExpression.GetAllRecursiveILRanges());
return(expr.AcceptVisitor(this, data));
}
else
{
return(base.VisitBinaryOperatorExpression(binaryOperatorExpression, data));
}
}
}