@Override
    public List<ValidationEvent> validate(Model model) {
        List<ValidationEvent> events = new ArrayList<>();

        for (OperationShape operation : model.getOperationShapesWithTrait(HttpTrait.class)) {
            validateOperationsWithHttpTrait(model, operation).ifPresent(events::add);
        }

        for (StructureShape structure : model.getStructureShapesWithTrait(ErrorTrait.class)) {
            validateError(structure, structure.expectTrait(ErrorTrait.class)).ifPresent(events::add);
        }

        return events;
    }
Ensures that HTTP response codes are appropriate for operations and errors.
smithy-model/src/main/java/software/amazon/smithy/model/validation/validators/HttpResponseCodeSemanticsValidator.java