Error for C# 8.0 on Mac: "Target runtime doesn't support default interface implementation"


Hello everyone!

I have a problem with Rider when compiling C# 8.0 code. Even tho I switched to the newest .NET / .NET Core (doesn't matter) and language version to 8.0, enabled Nullable Types etc. the code doesn't want to compile, it throws the following error "Target runtime doesn't support default interface implementation" on Rider for Mac. What's interesting, on Visual Studio 2019 for Mac (which is horrible by the way) everything works without a problem.

Do you know how can I fix that? I'd be grateful for help. 

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Hello Michał,

Please try Rider EAP as was suggested above.

And if the issue persists please create a YouTrack issue and attach:

  1. Rider logs collected using the following instructions
  2. Csproj file of the project.

Thank you in advance and have a great day!


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