DO variable for an implied-
DO construct in a
DATA statement may not be used as the
for an outer implied-
DO construct. For example, this
fragment is disallowed by
DATA ((A(I, I), I= 1, 10), I= 1, 10) /.../
This also is disallowed by Fortran 90, as it offers no additional capabilities and would have a variety of possible meanings.
Note that it is very unlikely that any production Fortran code tries to use this unsupported construct.