Implicit conversions

[domn1995]

As a dunet user, I want some unions to support assigning its members' inner values directly, so that my code is more terse and less noisy.

For example, we should be able to do this:

using Result = Result<System.Exception, string>;

// No `new Result.Err()` required here.
Result exception = new Exception("Boom!");
// No `new Result.Ok()` required here.
Result success = "Success!";
// Compiler error.
Result invalid = 1;

[Union]
public partial record Result<TError, TSuccess>
{
    partial record Ok(TSuccess Value);
    partial record Err(TError Error);
}

[domn1995]

This feature probably doesn't make sense for all union types. What is the best way to determine when the implicit conversions should be generated?

[domn1995]

This feature probably doesn't make sense for all union types. What is the best way to determine when the implicit conversions should be generated?

Here's some thoughts:

Restrictions

Union members may have implicit conversions if and only if the member has a single parameter (generic or not).

Feature Opt-in?

Should users opt into this feature or should all union members matching the above criteria get implicit conversions?

Nullability

How does null fit into this?