Attempt to match number of template arguments to prune references for unresolved lookup expressions

[varungandhi-src]

In the following code

template <typename T>
void f() {}

template <typename T, typename U>
void f() {}

template <typename T>
void g() { f<T>(); }

Here, even though f is unresolved, it cannot match the second case because U doesn't have a default value.