# Types with SWI-Prolog

**URL:** <https://swi-prolog.discourse.group/t/types-with-swi-prolog/1341>\
**Category:** Split Topic\
**Tags:** discussion\
**Created:** [October 2, 2019, 9:58am UTC](https://swi-prolog.discourse.group/t/types-with-swi-prolog/1341 "2019-10-02T09:58:55Z")\
**Posts on this page:** 1\
**Showing post:** 20

<div class="post-metadata">

**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\
**Post date:** [October 3, 2019, 9:30am UTC](https://swi-prolog.discourse.group/t/types-with-swi-prolog/1341/20 "2019-10-03T09:30:09Z")

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The current version already acts appropriate:

```prolog
?- check.
% Checking undefined predicates ...
% Checking trivial failures ...
Warning: The following goals fail because there are no matching clauses.
Warning: binary_tree(foo), which is called from
Warning: /ufs/wielemak/src/swipl-devel/linux/bt.pl:7:4: 1-st clause of foo/0
...

```

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