private BoundExpression MakeAsOperator(
BoundAsOperator oldNode,
SyntaxNode syntax,
BoundExpression rewrittenOperand,
BoundTypeExpression rewrittenTargetType,
Conversion conversion,
TypeSymbol rewrittenType)
{
// TODO: Handle dynamic operand type and target type
Debug.Assert(rewrittenTargetType.Type.Equals(rewrittenType));
// target type cannot be a non-nullable value type
Debug.Assert(!rewrittenType.IsValueType || rewrittenType.IsNullableType());
if (!_inExpressionLambda)
{
ConstantValue constantValue = Binder.GetAsOperatorConstantResult(rewrittenOperand.Type, rewrittenType, conversion.Kind, rewrittenOperand.ConstantValue);
if (constantValue != null)
{
Debug.Assert(constantValue.IsNull);
BoundExpression result = rewrittenType.IsNullableType() ? new BoundDefaultExpression(syntax, rewrittenType) : MakeLiteral(syntax, constantValue, rewrittenType);
if (rewrittenOperand.ConstantValue != null)
{
// No need to preserve any side-effects from the operand.
// We also can keep the "constant" notion of the result, which
// enables some optimizations down the road.
return(result);
}
return(new BoundSequence(
syntax: syntax,
locals: ImmutableArray <LocalSymbol> .Empty,
sideEffects: ImmutableArray.Create <BoundExpression>(rewrittenOperand),
value: result,
type: rewrittenType));
}
if (conversion.IsImplicit)
{
// Operand with bound implicit conversion to target type.
// We don't need a runtime check, generate a conversion for the operand instead.
return(MakeConversionNode(syntax, rewrittenOperand, conversion, rewrittenType, @checked: false));
}
}
return(oldNode.Update(rewrittenOperand, rewrittenTargetType, conversion, rewrittenType));
}
private BoundExpression MakeIsOperator(
BoundIsOperator oldNode,
SyntaxNode syntax,
BoundExpression rewrittenOperand,
BoundTypeExpression rewrittenTargetType,
Conversion conversion,
TypeSymbol rewrittenType)
{
if (rewrittenOperand.Kind == BoundKind.MethodGroup)
{
var methodGroup = (BoundMethodGroup)rewrittenOperand;
BoundExpression receiver = methodGroup.ReceiverOpt;
if (receiver != null && receiver.Kind != BoundKind.ThisReference)
{
// possible side-effect
return(RewriteConstantIsOperator(receiver.Syntax, receiver, ConstantValue.False, rewrittenType));
}
else
{
return(MakeLiteral(syntax, ConstantValue.False, rewrittenType));
}
}
var operandType = rewrittenOperand.Type;
var targetType = rewrittenTargetType.Type;
Debug.Assert((object)operandType != null || rewrittenOperand.ConstantValue.IsNull);
Debug.Assert((object)targetType != null);
// TODO: Handle dynamic operand type and target type
if (!_inExpressionLambda)
{
ConstantValue constantValue = Binder.GetIsOperatorConstantResult(operandType, targetType, conversion.Kind, rewrittenOperand.ConstantValue);
if (constantValue != null)
{
return(RewriteConstantIsOperator(syntax, rewrittenOperand, constantValue, rewrittenType));
}
else if (conversion.IsImplicit)
{
// operand is a reference type with bound identity or implicit conversion
// We can replace the "is" instruction with a null check
return(MakeNullCheck(syntax, rewrittenOperand, BinaryOperatorKind.NotEqual));
}
}
return(oldNode.Update(rewrittenOperand, rewrittenTargetType, conversion, rewrittenType));
}