Allow ref field of the containing type

[cston]

Allow the following:

ref struct R<T>
{
    public ref R<T> Next;
}

Relates to test plan #59194

[RikkiGibson]

Is this planned for C# 11?

[jaredpar]

Is this planned for C# 11?

No. This section of the proposal is attempting to keep track of what will make C# 11 vs. later releases

https://github.com/dotnet/csharplang/blob/main/proposals/low-level-struct-improvements.md#what-will-make-c-110

[John0King]

any news on here ?
demo link

since the ref field is a T& in IL and it size is fixed to 8 byte on x64, this could allow us to wirte a struct TreeNode<T> instead of using class

by the way, Java can optimize class to be allocate on stack , and I think that why it‘s "binary-trees“ benchamark faster than C#
https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/csharp.html

[jaredpar]

Closing as ref fields of ref struct are not permitted by the language spec. It's not specific to containing type.