I know the C++ Concepts proposal is intended, perhaps among other things, to place restrictions on template parameters (say, being a "Sequence"), over the current situation in which whatever manages to compile is good enough (and the error messages are abysmal).
But - what about namespaces? I mean, currently, we can't use them as template parameters, but one would think that if a method only uses the static methods and members of a class, then a namespace should also be a satisfactory thing to pass to it. Does the current version of / current implements of the Concepts proposal support that? If not, was this considered and rejected or just not considered?
Related question:
Is a class with only static methods better than a namespace with only non-member functions?
Concepts adds no mechanism to pass namespaces at compile or run time. So there is no way to test a namesoace against a conceot, or parametarize code with a namespace, barring macros.
The reflection TS may permit reflection over namespaces (I am not up to date on its current status), but that is orthogonal to concepts. Maybe reification and reflection of namespaces can be manipulated to permit concept checking of namespaces and passimg them around somehow, but if it does today it might not tomorrow and vice vers as it relies on two different plastic features where such a side effect would be accidental at best.