protected override Expression VisitConditional(ConditionalExpression c)
{
var test = Visit(c.Test);
var ifTrue = Visit(c.IfTrue);
var ifFalse = Visit(c.IfFalse);
if (test.NodeType.In(ExpressionType.Equal, ExpressionType.NotEqual))
{
var binaryExpression = (BinaryExpression)test;
var left = binaryExpression.Left.StripCasts();
var right = binaryExpression.Right.StripCasts();
if ((IsEntity(left) && IsNull(right)) || (IsEntity(right) && IsNull(left)))
{
var nullPart = c.Test.NodeType == ExpressionType.Equal ? ifTrue : ifFalse;
var memberAccessPart = c.Test.NodeType == ExpressionType.Equal ? ifFalse : ifTrue;
if (IsNull(nullPart) && memberAccessPart.StripCasts().NodeType == ExpressionType.MemberAccess)
{
var memberAccess = (MemberExpression)memberAccessPart.StripCasts();
if (ExpressionTree.Equals(memberAccess.Expression, IsNull(right) ? left : right))
{
return(memberAccessPart);
}
}
}
}
if (!ReferenceEquals(test, c.Test) || !ReferenceEquals(ifTrue, c.IfTrue) || !ReferenceEquals(ifFalse, c.IfFalse))
{
return(Expression.Condition(test, ifTrue, ifFalse));
}
return(c);
}
private static void AssertExpressionEquals(LambdaExpression expectedExpression, LambdaExpression actualExpression)
{
var equals = ExpressionTree.Equals(actualExpression, expectedExpression);
Assert.That(equals, "Expected expression '{0}' got '{1}'", expectedExpression.ToString(true), actualExpression.ToString(true));
}