In what .Net version "xOrDefault" linq methods became nullable?

[maxkoshevoi]

Right now SingleOrDefault is nullable: https://github.com/dotnet/runtime/blob/main/src/libraries/System.Linq/src/System/Linq/Single.cs#L32

But in .Net Standard 2.1 it's not. I'm using Xamarin, so cannot use anything higher than .Net Standard 2.1, but still curious, when did "?" was added there?

[GeraudFabien]

Well the change was done in this commit. Release in the version 16 days ago

[gfoidl]

I'd say it came with 122c438

The commit you linked changed

-[return: System.Diagnostics.CodeAnalysis.MaybeNullAttribute]
-public static T SingleOrDefault<T>(this System.Collections.Immutable.ImmutableArray<T> immutableArray) { throw null; }
+public static T? SingleOrDefault<T>(this System.Collections.Immutable.ImmutableArray<T> immutableArray) { throw null; }

[maxkoshevoi]

Oh, so it's not even present in a stable .Net version yet? Got it, thank you