Proposed resolution:

This wording is relative to N4023.

1. Change Table 3, [meta.trans.other] in the Library TS as indicated:

   Table 3 — Other type transformations

   Template	Condition	Comments
   …
   template <class Fn, class... ArgTypes> struct invocation_type<Fn(ArgTypes...)>;	Fn and all types in the parameter pack ArgTypes shall be complete types, (possibly cv-qualified) void, or arrays of unknown bound.	The nested typedef invocation_type<Fn(ArgTypes...)>::type shall be defined as follows. If raw_invocation_type<Fn(ArgTypes...)>::type does not exist, there shall be no member typedef type. Otherwise: Let A1, A2, … denote ArgTypes... Let R(T1, T2, …) denote raw_invocation_type_t<Fn(ArgTypes...)> Then the member typedef type shall name the function type R(U1, U2, …) where Ui is decay_t<Ai> if declval<Ai>() is an rvalue otherwise Ti. If raw_invocation_type<Fn(ArgTypes...)>::type is the function type R(T1, T2, …) and Fn is a pointer to member type and T1 is an rvalue reference, then R(decay<T1>::type, T2, …). Otherwise, raw_invocation_type<Fn(ArgTypes...)>::type.