Implicit fn template instantiation

[anthony.difranco at yale.edu]

Can someone explain why I can't instantiate this template implicitly andor
comment on whether I'm overlooking a better way to accomplish what this template
does?

template increment(T, K)
{
void increment(T[K] association, K key)
{
if(key in association)
{
association[key]++;
}
else
{
association[key] = 1;
}
}
}

Thanks,
Anthony