in module/geb-core/src/main/groovy/geb/content/PageContentTemplateParams.groovy [126:134]
private void validateRequired(required) {
def message = '''contains conflicting bounds and 'required' options'''
if (required == true && (min == 0 || max == 0)) {
throwInvalidContent(message)
}
if (required == false && min > 0) {
throwInvalidContent(message)
}
}