Thank you for additional clarification, I can see that some of related issues like https://github.com/dotnet/csharplang/issues/38 are not yet closed too, so it may cause additional confusion about its status.
I think that a C++'s const& equivalent would be very useful in C#, especially to simplify making objects and value types immutable by default and also more performant. I created https://github.com/dotnet/csharplang/issues/1118 as a starter point for discussion, although I'm not sure if linking it to "ref readonly" that's available for value types is the right association to make in terms of more general C# roadmap and design.
I think that a C++'s const& equivalent would be very useful in C#, especially to simplify making objects and value types immutable by default and also more performant. I created https://github.com/dotnet/csharplang/issues/1118 as a starter point for discussion, although I'm not sure if linking it to "ref readonly" that's available for value types is the right association to make in terms of more general C# roadmap and design.