Proposed resolution:
This wording is relative to N4529.
In Library Fundamentals 2, change [meta.trans.other] as indicated:
-3- Within this section, define the invocation parameters of INVOKE(f, t1, t2, ..., tN) as follows, in which T1 is the possibly cv-qualified type of t1 and U1 denotes T1& if t1 is an lvalue or T1&& if t1 is an rvalue:
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If f is a class object, the invocation parameters are the parameters matching t1, ..., tN of the best viable function (C++14 §13.3.3) for the arguments t1, ..., tN among the function call operators and surrogate call functions of f.
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