> we will also be upgrading to recent versions of the Mono C# compiler, base class libraries, and runtime for use in the editor
> We will continue to use the Mono C# compiler (and perhaps later, Roslyn). We will continue to use the Mono class libraries. All currently supported features and 3rd party libraries which work with Mono AOT should continue to work with IL2CPP. We are only seeking to provide a replacement for the Mono VM and AOT compiler, and will keep on leveraging the wonderful Mono Project.
Currently they support both - il2cpp isn't done yet. But as the blogpost calls it, it is the future of scripting in Unity.
Also, yes, this is a replacement for the VM and AOT, but the libraries in Mono are still very useful. Many of them are currently being replaced by Microsoft code as well, though, so it looks like .NET, Mono and il2cpp will share lots of code that way. Just not the VMs.
They are (apparently) using Mono (C# compiler + base class libraries + runtime) on the desktop for their IDE, and they are using IL2CPP and parts of Mono (C# compiler + base class libraries, but not the runtime) on their targets (iOS, Android, ...)
I don't know man. Mono moved away from Boehm GC to a real gc (SGen) because it never really worked for them bespite feeding it a lot of metadata.
Others before them have found out that tanspiling to C/C++ isn't really that great (some of the more recent ones where HipHop PHP).
> we will also be upgrading to recent versions of the Mono C# compiler, base class libraries, and runtime for use in the editor
> We will continue to use the Mono C# compiler (and perhaps later, Roslyn). We will continue to use the Mono class libraries. All currently supported features and 3rd party libraries which work with Mono AOT should continue to work with IL2CPP. We are only seeking to provide a replacement for the Mono VM and AOT compiler, and will keep on leveraging the wonderful Mono Project.