auto: useful, annoying or bad practice?

[Mark]

On Wednesday, 2 May 2018 at 14:05:49 UTC, H. S. Teoh wrote:
> How else would you do DoI, though?  With Concepts?  The 
> advantage of using structural typing over concepts for DoI is 
> that you would need an exponential number of concepts to catch 
> up with a linear number of optional fields in a structural 
> typing model.  Sure, structural typing has its warts, but it's 
> at least more scalable in this respect.
>
>
> T

Why? I don't think concepts force you to write a specific 
implementation for every possible combination of compile-time 
values.