Expressing range constraints in CNF form

[Andrei Alexandrescu via Digitalmars-d]

On 06/12/2017 03:18 AM, Walter Bright wrote:
> On 6/11/2017 5:13 PM, Adam D. Ruppe wrote:
>>        supportsFront!R &&
> 
> That doesn't work because there may be a local symbol:
> 
>      T front(R r) { }
> 
> which will not be in scope in supportsFront().

Yah, this was part of the original design: migrate all checks to 
std.traits. At a point I realized that queries of the form "does a.b 
work?" need to be accompanied by passing a number of modules to import 
in order to resolve possible UFCS for "b". At the moment I had a 
standard library artifact import a user-defined module, I decided things 
got too odd and gave up on that. -- Andrei