VQMC, chapter 16 (Attributes), page 264

     A declaration of a feature `f' introducing a manifest
     constant    is    valid    if   and   only   if   the
     Manifest_constant `m' used in the declaration matches
     the type `T' declared for `f' in one of the following
     ways:

       `m' is a Boolean_constant and `T' is `BOOLEAN'.

       `m' is a Character_constant and `T' is `CHARACTER'.

       `m' is an Integer_constant and `T' is `INTEGER'.

       `m'  is  a  Real_constant  and  `T'  is  `REAL'  or
          `DOUBLE'.

       `m' is a Manifest_string and `T' is `STRING'.

       `m' is a Bit_constant and `T' is a Bit_type.