"+=" (overloads) with custom array slices on both lhs, and rhs ??

[Paul Backus]

On Sunday, 5 September 2021 at 19:43:20 UTC, james.p.leblanc 
wrote:
> Dear D-ers,
>
> I have constructed a custom array type that works, but is 
> missing
> correct functioning on some operator overloads.

[...]

> ```d
> import std.stdio;
> import myarray_mod;
> ```

Please post the source code for `myarray_mod` so that we can 
reproduce the errors you're seeing.