Why is there no readonly ref record struct?

[hugener]

I'm an functional programming beginner, but wonder why there is no readonly ref record struct, now that we got record structs in C# 10?

Wouldn't that make for a powerful tool for FP in C# avoiding the cost of copying large structs/allocating record classes when doing recursion?

Not sure if I'm missing something obvious here, but for now I'm trying readonly ref struct, although I loose the simplified declaration that records have. Or why doesn't structs have record style declaration as well?

[CyrusNajmabadi]

You don't need a ref struct for this. Just use a readonly record struct, and pass using in.

[hugener]

Great thanks!

[hypeartist]

You don't need a ref struct for this`.

Oh, sure I do if I need to have a member of, say, ReadOnlySpan<> type

[CyrusNajmabadi]

you can use a readonly ref struct for that case.

[333fred]

record struct S implies implementing IEquatable<S>. ref structs cannot implement interfaces.

[aelij]

@333fred can we revisit this now that interfaces are supported? It could be a simple alternative to #2584, e.g. for passing Spans into String.Create().

[333fred]

We could, though I don't know how this would subsume #2584. Seems like that would still be wanted.