ReSharper ' MergeSequentialChecks '和' MergeSequentialChecksW

我想弄清楚这两个规则的区别是什么?

• MergeSequentialChecks
• MergeSequentialChecksWhenPossible

文档中没有提到第二种方法。https://www.jetbrains.com/help/resharper/2016.1/MergeSequentialChecks.html

我不太清楚WhenPossible是什么意思

如果ReSharper建议应用第一条规则并合并我的顺序检查，那么这确实是可能的。怎么会不可能呢?

下面是检查的代码示例。

public class Person
{
    public string Name { get; set; }
    public IList<Person> Descendants { get; set; }
}
public static class TestReSharper
{
    // Here `MergeSequentialChecks` rule is triggered for both `&&` operands.
    public static bool MergeSequentialChecks(Person person)
    {
        return person != null && person.Descendants != null && person.Descendants.FirstOrDefault() != null;
    }
    // Here `MergeSequentialChecksWhenPossible` rule is triggered.
    public static bool MergeSequentialChecksWhenPossible1(Person person)
    {
        return person != null && person.Descendants.Any();
    }
    // Here `MergeSequentialChecksWhenPossible` rule is triggered.
    public static bool MergeSequentialChecksWhenPossible2(Person person)
    {
        return person.Descendants != null && person.Descendants.Any();
    }
}

if (node != null && node.IsValid()) { ... }

if (node?.IsValid() == true) { ... }

if (stringBuilder != null) { // "Use null propagation"
  stringBuilder.Append("hello");
}

stringBuilder?.Append("hello");

if (stringBuilder != null) { // no suggestion
  stringBuilder.Append("hello");
  stringBuilder.Append("world");
  stringBuilder.Append("!!!");
}