modes_erroneous.m:020: In clause for `p(in, out)':
modes_erroneous.m:020:   mode error in conjunction. The next 2 error messages
modes_erroneous.m:020:   indicate possible causes of this error.
modes_erroneous.m:020: 
modes_erroneous.m:020:   In clause for `p(in, out)':
modes_erroneous.m:020:   in argument 1 of call to predicate
modes_erroneous.m:020:   `modes_erroneous.p'/2:
modes_erroneous.m:020:   mode error: variable `V_5' has instantiatedness
modes_erroneous.m:020:   `free',
modes_erroneous.m:020:   expected instantiatedness was `ground'.
modes_erroneous.m:020: 
modes_erroneous.m:019:   In clause for `p(in, out)':
modes_erroneous.m:019:   in argument 2 of clause head:
modes_erroneous.m:019:   mode error in unification of `HeadVar__2' and `X'.
modes_erroneous.m:019:   Variable `HeadVar__2' has instantiatedness `free',
modes_erroneous.m:019:   variable `X' has instantiatedness `free'.