I’m most excited for the “value types as references” such as ref returns an “in”-parameters. I often use arrays of structs for memory locality, and they often grow larger than the size where they can be passed in registers. In a 64bit app with all double precision floats there isn’t much you can do with 16 bytes or less.

Being able to send 3 structs of e.g 32 bytes each (such as Vector4<double>) to a function without hidden copying will be great.