public override BoundNode VisitLoweredConditionalAccess(BoundLoweredConditionalAccess node)
{
var receiverRefKind = ReceiverSpillRefKind(node.Receiver);
BoundSpillSequenceBuilder receiverBuilder = null;
var receiver = VisitExpression(ref receiverBuilder, node.Receiver);
BoundSpillSequenceBuilder whenNotNullBuilder = null;
var whenNotNull = VisitExpression(ref whenNotNullBuilder, node.WhenNotNull);
BoundSpillSequenceBuilder whenNullBuilder = null;
var whenNullOpt = VisitExpression(ref whenNullBuilder, node.WhenNullOpt);
if (whenNotNullBuilder == null && whenNullBuilder == null)
{
return(UpdateExpression(receiverBuilder, node.Update(receiver, node.HasValueMethodOpt, whenNotNull, whenNullOpt, node.Id, node.Type)));
}
if (receiverBuilder == null)
{
receiverBuilder = new BoundSpillSequenceBuilder();
}
if (whenNotNullBuilder == null)
{
whenNotNullBuilder = new BoundSpillSequenceBuilder();
}
if (whenNullBuilder == null)
{
whenNullBuilder = new BoundSpillSequenceBuilder();
}
BoundExpression condition;
if (receiver.Type.IsReferenceType || receiver.Type.IsValueType || receiverRefKind == RefKind.None)
{
// spill to a clone
receiver = Spill(receiverBuilder, receiver, RefKind.None);
var hasValueOpt = node.HasValueMethodOpt;
if (hasValueOpt == null)
{
condition = _F.ObjectNotEqual(
_F.Convert(_F.SpecialType(SpecialType.System_Object), receiver),
_F.Null(_F.SpecialType(SpecialType.System_Object)));
}
else
{
condition = _F.Call(receiver, hasValueOpt);
}
}
else
{
Debug.Assert(node.HasValueMethodOpt == null);
receiver = Spill(receiverBuilder, receiver, RefKind.Ref);
var clone = _F.SynthesizedLocal(receiver.Type, _F.Syntax, refKind: RefKind.None, kind: SynthesizedLocalKind.Spill);
receiverBuilder.AddLocal(clone);
// (object)default(T) != null
var isNotClass = _F.ObjectNotEqual(
_F.Convert(_F.SpecialType(SpecialType.System_Object), _F.Default(receiver.Type)),
_F.Null(_F.SpecialType(SpecialType.System_Object)));
// isNotCalss || {clone = receiver; (object)clone != null}
condition = _F.LogicalOr(
isNotClass,
_F.MakeSequence(
_F.AssignmentExpression(_F.Local(clone), receiver),
_F.ObjectNotEqual(
_F.Convert(_F.SpecialType(SpecialType.System_Object), _F.Local(clone)),
_F.Null(_F.SpecialType(SpecialType.System_Object))))
);
receiver = _F.ComplexConditionalReceiver(receiver, _F.Local(clone));
}
if (node.Type.IsVoidType())
{
var whenNotNullStatement = UpdateStatement(whenNotNullBuilder, _F.ExpressionStatement(whenNotNull));
whenNotNullStatement = ConditionalReceiverReplacer.Replace(whenNotNullStatement, receiver, node.Id, RecursionDepth);
Debug.Assert(whenNullOpt == null || !LocalRewriter.ReadIsSideeffecting(whenNullOpt));
receiverBuilder.AddStatement(_F.If(condition, whenNotNullStatement));
return(receiverBuilder.Update(_F.Default(node.Type)));
}
else
{
var tmp = _F.SynthesizedLocal(node.Type, kind: SynthesizedLocalKind.Spill, syntax: _F.Syntax);
var whenNotNullStatement = UpdateStatement(whenNotNullBuilder, _F.Assignment(_F.Local(tmp), whenNotNull));
whenNotNullStatement = ConditionalReceiverReplacer.Replace(whenNotNullStatement, receiver, node.Id, RecursionDepth);
whenNullOpt = whenNullOpt ?? _F.Default(node.Type);
receiverBuilder.AddLocal(tmp);
receiverBuilder.AddStatement(
_F.If(condition,
whenNotNullStatement,
UpdateStatement(whenNullBuilder, _F.Assignment(_F.Local(tmp), whenNullOpt))));
return(receiverBuilder.Update(_F.Local(tmp)));
}
}
