What type does byGrapheme() return?

[Alex]

On Monday, 6 January 2020 at 08:39:19 UTC, Robert M. Münch wrote:
> On 2020-01-05 04:18:34 +0000, H. S. Teoh said:
>
>> At a minimum, I think we should file a bug report to 
>> investigate whether
>> Grapheme.opSlice can be implemented differently, such that we 
>> avoid this
>> obscure referential behaviour that makes it hard to work with 
>> in complex
>> code. I'm not sure if this is possible, but IMO we should at 
>> least
>> investigate the possibilities.
>
> Done... my first bug report :-) I copied togehter all the 
> findings from this thread.

For the sake of completeness
https://issues.dlang.org/show_bug.cgi?id=20483