x:012: In module `bug10':
x:012:   warning: module `list' is imported in the interface, but it is not
x:012:   used in the interface.
x:013: Warning: this `:- import_module' declaration for module `io' is out of
x:013:   order with respect to the preceding `:- import_module' declaration for
x:013:   module `list'.
x:020: In clause for predicate `main'/2:
x:020:   error: call to undefined predicate `foo'/2.