OT: C# now has ref and const ref return

[XavierAP]

https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/ref#reference-return-values

This is a good example how C# is getting very competitive not 
only on the high-productivity segment (which Dlang currently 
neglects relatively), but expanding into higher performance. The 
only point of these new features is to enable writing C# code 
that does not allocate in the GCed heap. I think D should pay 
attention

See also:
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/ref#ref-struct-types

Syntactical design-wise they have opted for total explicitness. 
Everything has to be decorated ref: function declaration, return 
statement, and local variable declaration at caller scope. (This 
makes it look at first like it's allowing ref local variable 
declarations like C++, but I understand -- haven't played with it 
yet -- that in reality it's only allowed at the left side of 
calls to ref return methods.) I guess this explicit approach may 
be safer and works for C# since it by design doesn't have 
templates/heterogeneous generics, but polymorphic/homogeneous.

Note in case you're not familiar that C# readonly means D 
immutable and C# const means D enum.