template<class OuterA1, class OuterA2, class... InnerAllocs> bool operator==(const scoped_allocator_adaptor<OuterA1, InnerAllocs...>& a, const scoped_allocator_adaptor<OuterA2, InnerAllocs...>& b) noexcept;
a.outer_allocator() == b.outer_allocator()
a.outer_allocator() == b.outer_allocator() && a.inner_allocator() == b.inner_allocator()