private static String toString(ImmutableSDField field) {
        return field.getName() + " (" + String.join(", ", getStructFieldAttributes(field.getStructFields(), false)) + ")";
    }
Validates that complex fields (of type struct or map) that have struct field attributes are supported.

Only applies for indexed search clusters.

@author geirst
config-model/src/main/java/com/yahoo/vespa/model/application/validation/ComplexFieldsWithStructFieldAttributesValidator.java