Template constraints in D

[Walter Bright]

Lutger wrote:
> Whether this is compelling *for D* I don't know.

My general approach is unless compelling use cases can be found for D, 
it isn't worth implementing (because there are already many ideas with 
compelling use cases).

I think the jury will be out for 3 or 4 years for C++ concept maps as to 
whether the identified use cases are compelling or not.