• list_undefined/0 reports undefined predicates
• list_trivial_fails/0 reports calls for which there is no matching clause.
• list_format_errors/0 reports mismatches in format/2,3 templates and the list of arguments.
• list_redefined/0 reports predicates that have a local definition and a global definition. Note that these are not errors.
• list_void_declarations/0 reports on predicates with defined properties, but no clauses.
• list_autoload/0 lists predicates that will be defined at runtime using the autoloader.
• check_predicate_options/0 tests for options passed to predicates such as open/4 that are unknown or are used with an invalid argument.

The checker can be expanded or restricted by modifying the dynamic multifile hook checker/2.

The checker may be used in batch, e.g., for CI workflows by calling SWI-Prolog as below. Note that by using -l to load the program, the program is not started if it used initialization/2 of type main to start the program.

swipl -q --on-warning=status --on-error=status \
      -g check -t halt -l myprogram.pl