collection expressions for Option<T>

[FreeApophis]

Since we have the pattern match for Option [var value] with C#12 the question is: should an Option<T> be constructible with a collection expression too?

• Option<T>.None would become []
• Option.Some(value) would become [value]

Open questions.

• this could be an opportunity to remove the implicit operator. (breaking change)
• What would we do if there is more than one value Option<int> number = [42, 1337];
  • We have ignored the problems for the pattern, because you can write such a pattern, but it will never be matched.
  • This could be abused as a abbrevation for SingleOrNone() or FirstOrNone() depending on the decided behaviour in combination with the spread operator. Option<int> number = [..collection];
• Do we really want that?

What would we need to do?

Implement the Collection Builder as described here:
https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/collection-expressions