On Thursday, 1 August 2024 at 14:20:29 UTC, user1234 wrote:

We are only talking about it in the context of returning from a function.

struct S {int i;}
function f(S s);
function f(int i);

unittest { f(0); } // both match

You are wasting my time. Show me how this applies to retuning from within a function.

On Thursday, 1 August 2024 at 07:25:53 UTC, Emma wrote:

Option!int something() {
  return None(); // Error: cannot implicitly convert expression `None()` of type `None` to `Option!int`
}

Not D per se, but you can check Adam D. Ruppe's current work.
If I am not mistaken, the thing you are asking for is already possible in the nightly release.

https://dpldocs.info/this-week-in-arsd/Blog.Posted_2024_02_20.html#implicit-construction

Juraj