Checking if a function definition is a of a member function

[deadlocklogic]

As the title says consider:

class A
{
public:
    void a();
};
// Impl
void A::a()
{
}

Is there a way to check if a (Impl) is an outer member function definition? (without creating a manual hierarchy)?
@foonathan Any thoughts?

[deadlocklogic]

Ok cpp_forward_declarable::semantic_parent does the job. Thanks!