freefree.m:020: In predicate `p'/0:
freefree.m:020:   warning: unresolved polymorphism.
freefree.m:020:   The variables with unbound types were:
freefree.m:020:     Y: V_1
freefree.m:020:     X: V_1
freefree.m:020:   The unbound type variables will be implicitly bound to the
freefree.m:020:   builtin type `void'.
freefree.m:020:   The body of the clause contains a call to a polymorphic
freefree.m:020:   predicate, but I can't determine which version should be
freefree.m:020:   called, because the type variables listed above didn't get
freefree.m:020:   bound. (I ought to tell you which call caused the problem,
freefree.m:020:   but I'm afraid you'll have to work it out yourself. My
freefree.m:020:   apologies.)
freefree.m:023: In clause for `p':
freefree.m:023:   mode error in unification of `X' and `Y'.
freefree.m:023:   Variable `X' has instantiatedness `free',
freefree.m:023:   variable `Y' has instantiatedness `free'.