c#-7.2

Everyone is writing about how great the new type Span<T> is so I eagerly wanted to start rewriting a couple of methods in my libraries but where do I actually find it? I've updated Visual Studio 2017 to the latest version 15.5.0 where the change-log says: The C# compiler now supports the 7.2 set of language features including: Support for the Span<T> type being used throughout Kestrel and CoreFX via the ref struct modifier. but when I try to use it my code I'm getting an error and intellisense cannot resolve it. It's a .net 4.6.2 project and the language version is set to latest minor . Do I

So, I (think I) understand what the in parameter modifier does. But what it does appears to be quite redundant. Usually, I'd think that the only reason to use a ref would be to modify the calling variable, which is explicitly forbidden by in . So passing by in reference seems logically equivalent to passing by value. Is there some sort of performance advantage? It was my belief that on the back-end side of things, a ref parameter must at least copy the physical address of the variable, which should be the same size as any typical object reference. So, then is the advantage just in larger

As part of the Roslyn documentation on GitHub, there's a page called Language feature implementation status , with planned language features for C# and VB. One feature I couldn't wrap my head around was private protected access modifier: private protected string GetId() { … } There is also a page of C# Language Design Notes , which explains many new features, but not this one. Eric Lippert said in a comment : Your error is in thinking of the modifiers as increasing restrictions. The modifiers in fact always decrease restrictions. Remember, things are "private" by default; only by adding