Also note that in a world with perfect forwarding, we shuold
probably specify fill() like

template< class Rng >
void fill( Rng&& rng, range_value<Rng>::type x );

Wouldn't this stop fill from working on ranges of abstract types?

I don't know. Usually when deal with abstract types, I don't use fill()
for anything because those types are not copyable or assignable.

-Thorsten

I have infrequently have abstract types that are assignable. I don't think this alters your key point about the forwarding but I think we should probably have this instead:

template< class Range, class Value >

void fill( Rng&& rng, const Value& x );

Where 'Value' is required to be convertible to one of the right-hand side arguments of an assignment to a range_value<Rng>::type.

Does this look sensible to you?

Regards,

Neil Groves