Feature request: Add debugger support to compiler-generated class behind IReadOnly collection expression

[LWChris]

Put this code in a .NET 9/C#13 console app and launch in debug mode:

using System.Collections.ObjectModel;
using System.Diagnostics;

var names1 = GetNames1();
var names2 = GetNames2();
Debugger.Break();
static IReadOnlyCollection<string> GetNames1() => ["Alice", "Bob", "Charlie"];
static IReadOnlyCollection<string> GetNames2() => new ReadOnlyCollection<string>(["Alice", "Bob", "Charlie"]);

The QoL difference between debugging names1 and names2 is tremendous:

It's because names1 is a compiler-generated type without any debugger support, while ReadOnlyCollection for names2 and similar classes all feature amenity attributes like

[DebuggerTypeProxy(typeof(ICollectionDebugView<>))]
[DebuggerDisplay("Count = {Count}")]

Can the compiler-generated class for IReadOnlyCollection<T> and IReadOnlyList<T> collection expressions get support for a prettified debug view, too?

[RikkiGibson]

Feel free to file this as an issue (or click "Create issue from discussion" if it is available to you). I think it would be reasonable to just take a PR to make this change. No language spec change needed.

[LWChris]

I can "Reference in new issue" from the three dot menu on the original post. Not sure if that is what you are referring to?

[RikkiGibson]

That would work fine thanks!

[LWChris]

See #78651. Thank you.