LDM Notes for July 12th, 2023

[333fred]

https://github.com/dotnet/csharplang/blob/main/meetings/2023/LDM-2023-07-12.md

Agenda

• Collection Literals
  • Create methods
  • Extension methods
• Interceptors

[mungojam]

have I understood correctly from the point on collection literals extension methods that for now the below is true?

we won't be able to do:

var a = [1, 2, 3].AsImmutableArray();

but we will be able to do:

var a = AsImmutableArray([1, 2, 3])

assuming we have a function like:

public static ImmutableArray<T> AsImmutableArray<T>(this ImmutableArray<T> array) {
     return array;
}

[CyrusNajmabadi]

@mungojam correct. and that method can be a static method you bring in with a static-using.

[huoyaoyuan]

now, instead of an out Span that the compiler would write into, the compiler passes in a ReadOnlySpan, which the collection will then copy out of

Will non-copy initialization of ImmutableArray still be supported in this release?

[CyrusNajmabadi]

Yes. That is the intent.

[huoyaoyuan]

What API will be used then?

[CyrusNajmabadi]

https://learn.microsoft.com/en-us/dotnet/api/system.runtime.interopservices.immutablecollectionsmarshal.asimmutablearray?view=net-8.0

[huoyaoyuan]

Is there any attribute connecting the method? Or is it a specially known initializer?
I do want to see less things specially known.

[CyrusNajmabadi]

It's specially known.