private List<ErrorMessage> validate(Query query, IndexFacts.Session indexFacts) {
        ValidatePredicateVisitor visitor = new ValidatePredicateVisitor(indexFacts);
        ToolBox.visit(visitor, query.getModel().getQueryTree().getRoot());
        return visitor.errorMessages;
    }
Checks that predicate queries don't use values outside the defined upper/lower bounds.

@author Magnar Nedland
container-search/src/main/java/com/yahoo/prelude/searcher/ValidatePredicateSearcher.java