I do not understand copy constructors

[Paul Backus]

On Friday, 13 August 2021 at 15:26:15 UTC, Steven Schveighoffer 
wrote:
> The issue is that you can't convert const (or immutable or 
> mutable) to inout implicitly, and the member variable is inout 
> inside an inout constructor. Therefore, there's no viable copy 
> constructor to call for the member, and the outer copy 
> constructor cannot be generated.

I'm not quite sure I follow this. Are you saying that the 
constructor call is typechecked as if it were written like this:

```d
this.field = this.field.__ctor(rhs.field);
```

...and not like this?

```d
this.field.__ctor(rhs.field);
```

Because I can see how the first version would involve an 
const-to-inout conversion, but the second version looks like it 
ought to work.