Extensions and Generic Constraints

[fitdev]

Really excited to see Shapes/Roles finally being implemented (hopefully in C# 13) via implicit and explicit Extensions. Since it was mentioned several times by the team that the functionality of existing extension methods will be fully available via new implicit extensions, I wanted to know if it applies to generic constraints:

Current C#

public static int Area<TRect>(this TRect r) where TRect : IRectangle<int> => ...

Future C#

public implicit extension RectangleExtension<TRect> for TRect where TRect : IRectangle<int> { //NOTE: TRect - generic (constrained) type parameter and not a concrete type

  public int Area => ...

}

So will syntax like the one above be used, or some other syntax, or such feature will not be supported?

Generic constraints like this are hugely useful for performance reasons, because if structs are involved they will not be boxed due to JIT optimizations. Hopefully with the new extensions this functionality will be preserved.