Switch to C# 8.0

[ilexp]

Summary

We're currently using C# 7.3. Once C# 8.0 is stable and released, consider upgrading in order to access language features like readonly members (see #600).

Analysis

• C# 7.3 is the last version that will be supported on .NET Framework.
• C# 8.0 requires .NET Core 3.0 or .NET Standard 2.1 (also, see here), which isn't implemented in .NET Framework.
• Upgrading to C# 8.0 can only take place after previously upgrading the project to .NET Core 3.0 and .NET Standard 2.1.
• Wait until the overall environment is ready, then proceed with this issue.

[Rick-van-Dam]

Nullable references should work even on older .NET framework versions and so do alot of other features. Not everything though but that doesn't stop us from using C#8.0.

Microsoft does not officially support it though. So might still be better to wait a bit.

[CodingMadness]

Is it possible by now to use Duality with C# 8.0? Would be nice tho

And generally, when can we expect Duality 4.0? is it still under development or was it (hopefully not) aborted?