More complexity creep in Phobos

[Andrei Alexandrescu]

On 3/30/19 3:22 PM, Jonathan M Davis wrote:
> Either way, isConvertibleToString must go.

Word.

We should have one rcstring type that is reference counted, uses UTF8, 
is not a range, offers ranges (bytes, codepoints, graphemes), and 
consolidate around it. Algorithms should only use ranges, and whenever 
someone wants to use an algorithm with a string, they choose the 
iteration mode that fits the application.