Implicit conversion to mutable if no indirections?

[Simen Kjærås]

On Tuesday, 6 September 2022 at 17:45:50 UTC, Nick Treleaven 
wrote:
> On Tuesday, 6 September 2022 at 10:06:59 UTC, Quirin Schroll 
> wrote:
>> * Aforementioned `const(int*)` becoming `const(int)*`. That 
>> does not happen with custom `struct S(T)` automatically even 
>> in cases where it is provably correct, and there is no way to 
>> tell the D compiler that copies of `const(S!int)` are better 
>> understood to be `S!(const int)`.
>
> There is at least a library pattern:
> https://dlang.org/blog/2020/06/25/a-pattern-for-head-mutable-structures/

I really wish that had gone somewhere. There's not a lot of code 
to it, it's almost all library code that the user doesn't see, 
and it would provide a solution while we wait for the promised 
compiler support for the same thing (which I don't think would be 
very different - you'll need to specify the behavior for complex 
cases anyway). Also, it's not worth a whole lot as a library if 
Phobos doesn't implement it.

--
   Simen