Proposed resolution:

This wording is relative to N4810.

1. Modify [time.cal.year.members] as indicated:

   constexpr bool ok() const noexcept;
   

   -18- Returns: min().y_ <= y_ && y_ <= max().y_.

[ 2019-06-13; Priority to 0 and Status to Tentatively Ready after seven positive votes on the reflector. ]

The expression in the Returns element of year::ok in [time.cal.year.members] p18:

min() <= y_ && y_ <= max()

is ill-formed, as it attempts to compare type short (type of y_ member) with type year (type of year::min() and year::max()).