Linkage of explicit class template instantiation

Are multiple instantiations of the same class template with the same type allowed in different compilation units? What about function templates?

A sample code is as follow:

test.hpp

template <typename T>
class A
{
    public:
        T out();
};

template <typename T>
T A<T>::out()
{
    return T(1);
}

test1.cpp

#include "test.hpp"
template class A<int>;
int testFn()
{
    return A<int>().out();
}

test2.cpp

#include "test.hpp"
template class A<int>;
extern int testFn();
int main()
{
    return testFn() == A<int>().out();
}

If I run

g++ -std=c++11 test1.cpp test2.cpp -o test

it compiles without complaining duplicated definitions.

I was refering to an old draft of standard [1], and assuming linkage part doesn't change too much (except for anonymous namespaces). The class template has external linkage by 3.5.4 and 14.0.4. If that's the case, I would reason that g++ should complain duplicated definitions of A::out(). Am I missing something here?

What if test.hpp defines a function template without "static" or "inline" instead?

Thank you.

[1] http://ift.tt/1JaUT74