C# Have TryGetNonEnumeratedCount check for IReadOnlyCollection<T>

[vsfeedback]

This issue has been moved from a ticket on Developer Community.

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You can have a type that has a Count property and implements IEnumerable but not any of the collection interfaces.
The IReadOnlyCollection interface provides just that.

Currently, Enumerable.TryGetNonEnumeratedCount does not check for IReadOnlyCollection and therefore these types will be fully enumerated when trying to determine the count.

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Original Comments

Feedback Bot on 2/27/2024, 09:37 PM:

(private comment, text removed)

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[stephentoub]

Duplicate of #42254