Documentation: C#9 language features and netstandard2.0

[ptr1120]

I did not find any documentation about which of the new C#9 language features are supported in a library that targets netstandard2.0.
My questions:

1. Records (Champion "Records" (VS 16.8, .NET 5) csharplang#39): are currently working with netstandard 2.0, is this a supported feature?
2. Covariant Returns (Champion "Covariant Return Types" (VS 16.8, .NET 5) csharplang#49), are currently not working, any chance to get this working with netstandard 2.0?

Thank you and best regards!

[PathogenDavid]

Officially speaking, C#9 is only officially supported on .NET 5.

2. Covariant Returns (dotnet/csharplang#49), are currently not working, any chance to get this working with netstandard 2.0?

Covariant returns require support from the runtime, so they will never work on .NET Standard 2.0

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That being said, as you've noticed some feature work just fine. @Sergio0694 Has a nice write-up of what works on unsupported runtimes. (Some features require a small amount of work on your part to make them work.)

[ptr1120]

Thank you very much.

[PathogenDavid]

No problem!