void verify(ErrorCollector errorCollector, @Nullable List<Object> values, @Nullable String text, int line, int column, @Nullable String message) {
      if (HamcrestFacade.matches(matcher, actual)) return;

      if (values != null) {
        CollectionUtil.setLastElement(values, shortSyntax ? actual : false);
        replaceMatcherValues(values);
      }

      String description = HamcrestFacade.getFailureDescription(matcher, actual, message);
      Condition condition = new Condition(values, text, TextPosition.create(line, column), description, null, null);
      errorCollector.collectOrThrow(new ConditionNotSatisfiedError(condition));
    }
A condition of the form "foo equalTo(bar)" or "that(foo, equalTo(bar)"
or "expect(foo, equalTo(bar)", where 'equalTo' returns a Hamcrest matcher.
spock-core/src/main/java/org/spockframework/runtime/SpockRuntime.java