Steven Watanabe wrote:

AMDG

er wrote:

...

The example below illustrates my intent, but obviously it's not the right approach... so I'm hoping someone has a suggestion.

template<typename X> struct enforce_constness{ typedef add_reference<const X> type; };

template struct A{

template<typename X> void operator()(typename T<X>::type x)const{ // Under default I'd like const X& };

}

X x; A<> a; a(x);

no match for call to (A<T>)(X&)

It's impossible to deduce what the template parameter should be.

The easiest way is to use a forwarding function that optionally adds const. template<typename X> void call_impl(X& x) const;

template<typename X> void operator()(const X& x) { return(call_impl(x)); } template<typename X> void operator()(X& x) { return(call_impl(static_cast(x))); }

Thanks!

BTW, your subject line is a bit misleading because this has nothing to do with ADL

In Christ, Steven Watanabe