Simple and effective approaches to constraint error messages

[Meta via Digitalmars-d]

On Tuesday, 26 April 2016 at 15:56:55 UTC, Andrei Alexandrescu 
wrote:
> On 04/26/2016 11:35 AM, Meta wrote:
>> The nice part about 1 is that every constraint gets it for 
>> free.
>
> Only if in CNF, otherwise needs changed. -- Andrei

True, but I bet the majority of template constraints are in this 
form. The wiki page you linked also says that clauses that are 
not in CNF can be rewritten in CNF, but doing that automatically 
in the compiler would probably be difficult, bug-ridden, and 
annoying for end users.

Are you familiar with Nim's implementation of concepts? I think 
somebody actually implemented something close to this in D using 
inheritance and introspection.

http://nim-lang.org/docs/manual.html#generics-concepts