Proposed resolution:

This wording is relative to N4762.

• Edit [stack.defn], class template stack definition, as indicated:

  template<class... Args>
    decltype(auto) emplace(Args&&... args)
      { return c.emplace_back(c.end(), std::forward<Args>(args)...); }
  

• Edit [queue.defn], class template queue definition, as indicated:

  template<class... Args>
    decltype(auto) emplace(Args&&... args)
      { return c.emplace_back(c.end(), std::forward<Args>(args)...); }
  

Any sequence container supporting operations back(), push_back() and pop_back() can be used to instantiate stack.

but then in [stack.defn] we have the following code:

template<class... Args>
  decltype(auto) emplace(Args&&... args)
    { return c.emplace_back(std::forward<Args>(args)...); }

The same pattern appears in [queue].

The calls to c.emplace_back(std::forward<Args>(args)...) should be replaced with c.emplace(c.end(), std::forward<Args>(args)...).

We can do this w/o messing with the list above because emplace is part of the sequence container requirements, while emplace_back is not.