Proposed resolution:

This wording is relative to N4971.

1. Modify [util.smartptr.shared.create] as indicated:

   [Drafting note: As the issue submitter prefers option (2), this is wording for that.]

   template<class T, ...>
     shared_ptr<T> make_shared(args);
   template<class T, class A, ...>
     shared_ptr<T> allocate_shared(const A& a, args);
   template<class T, ...>
     shared_ptr<T> make_shared_for_overwrite(args);
   template<class T, class A, ...>
     shared_ptr<T> allocate_shared_for_overwrite(const A& a, args);
   

   -2- Preconditions: […]

   […]

   -7- Remarks:

   1. (7.1) — […]

   2. […]

   3. (7.5) — When a (sub)object of a non-array type U is specified to have an initial value of v, or U(l...), where l... is a list of constructor arguments, allocate_shared shall initialize this (sub)object via the expression

      1. (7.5.1) — allocator_traits<A2>::construct(a2, pv, v) or

      2. (7.5.2) — allocator_traits<A2>::construct(a2, pv, l...)

      respectively, where pv has type remove_cv_t<U>* and points to storage suitable to hold an object of type U and a2 of type A2 is a rebound copy of the allocator a passed to allocate_shared such that its value_type is remove_cv_t<U>.

   4. (7.6) — […]

   5. (7.7) — When a (sub)object of non-array type U is specified to have a default initial value, allocate_shared shall initialize this (sub)object via the expression allocator_traits<A2>::construct(a2, pv), where pv has type remove_cv_t<U>* and points to storage suitable to hold an object of type U and a2 of type A2 is a rebound copy of the allocator a passed to allocate_shared such that its value_type is remove_cv_t<U>.