Overlapping functionality: IFTI, templates, is-expressions

[Russell Lewis]

Bill Baxter wrote:
> Are you saying templates don't need to overload across modules?  If so, 
> what is the D alternative to the non-intrusive traits template pattern 
> used in C++?

I tried, but I failed, to shortcut that rabbit trail.  So let me take 
the next step, and repeat the subtle problems with silent cross-module 
overloading.

The problem comes about when two different programmers, in different 
libraries, write templates with the same name.  Say that programmer A 
writes a template foo with two specializations:

BEGIN CODE
	template foo(int A,TPL...) { ... }
	template foo(TPL...)       { ... }
END CODE

Now, ages later, when somebody links that with another library, we find 
this template:

BEGIN CODE
	template foo(char c,TPL...) { ... }
END CODE

Now, when you use the template:
	alias foo!('c') myTemplateInstance;
which library are you trying to use?