annotations_of should not instantiate class template specializations

[katzdm]

Calling annotations_of(^^Cls<int>) should not trigger an instantiation of Cls<int> - but note that the needle needs to be carefully threaded here, as the dependent annotation expressions do need to be instantiated and attached to the specialization's Decl. e.g.,

#include <experimental/meta>

template <class T>
struct [[=1]] C {
    consteval {
        if (sizeof(T) == 1) {
            annotate(^^C<T>, std::meta::reflect_value(42));
        }
    }
};

template <>
struct C<int> { };

static_assert(annotations_of(^^C<bool>).size() == 1);
static_assert(annotations_of(^^C<int>).size() == 0);

(godbolt)