Proposed resolution:

This wording is relative to N3691.

1. Modify [forwardlist.ops] p6 as indicated:

   void splice_after(const_iterator position, forward_list& x, const_iterator i);
   void splice_after(const_iterator position, forward_list&& x, const_iterator i);
   

   […]

   -6- Effects: Inserts the element following i into *this, following position, and removes it from x. The result is unchanged if &x == this and the following condition is satisfied: position == i or position == ++i. Pointers and references to *++i continue to refer to the same element but as a member of *this. Iterators to *++i continue to refer to the same element, but now behave as iterators into *this, not into x.

2. Modify [list.ops] p7 as indicated:

   void splice(const_iterator position, list& x, const_iterator i);
   void splice(const_iterator position, list&& x, const_iterator i);
   

   -7- Effects: Inserts an element pointed to by i from list x before position and removes the element from x. The result is unchanged if &x == this and the following condition is satisfied: position == i or position == ++i. Pointers and references to *i continue to refer to this same element but as a member of *this. Iterators to *i (including i itself) continue to refer to the same element, but now behave as iterators into *this, not into x.