Constrained Templates

[Walter Bright]

Nick Sabalausky wrote:
> "and a line number pointing into the template body. The error is being 
> reported as occurring somewhere other than where the actual problem is"
> 
> That would be a good place to point out that recent versions of DMD display 
> template instantiation traces upon template instatiation errors (Does C++ do 
> that?). Then, of course, it could go on to "but better yet...".

I wished to avoid quality of implementation issues, and instead focus on 
characteristics of the language.