Proposed resolution:

This wording is relative to N4810.

1. Modify [functional.syn], header <functional> synopsis, as indicated:

   template<class T> struct unwrap_reference;
   template<class T> using unwrap_reference_t = typename unwrap_reference<T>::type;
   template<class T> struct unwrap_ref_decay : unwrap_reference<decay_t<T>> {};
   template<class T> using unwrap_ref_decay_t = typename unwrap_ref_decay<T>::type;
   

2. Modify [refwrap.unwrapref] as indicated:

   template<class T>
     struct unwrap_reference;
   

   -1- If T is a specialization […]

   template<class T>
     struct unwrap_ref_decay;
   

   -?- The member typedef type of unwrap_ref_decay<T> denotes the type unwrap_reference_t<decay_t<T>>.

[ 2019-04-30 Priority to 0 and Status to Tentatively Ready after six positive votes on the reflector. ]

P0318R1 was discussed in Batavia and the requested changes were made in D0318R2. In San Diego the R1 paper was voted into the WP, despite not having the requested changes. There were also changes to D0318R2 suggested on the reflector, which are incorporated below.