Add support by yielding by-reference

1 files changed, 4 insertions, 4 deletions

diff --git a/Zend/zend_generators.c b/Zend/zend_generators.c
index bccbb48ca4..20ab9b16c6 100644
--- a/Zend/zend_generators.c
+++ b/Zend/zend_generators.c
@@ -661,12 +661,12 @@ zend_object_iterator *zend_generator_get_iterator(zend_class_entry *ce, zval *ob
 	zend_generator_iterator *iterator;
 	zend_generator *generator;
 
-	if (by_ref) {
-		zend_error(E_ERROR, "By reference iteration of generators is currently not supported");
-	}
-
 	generator = (zend_generator *) zend_object_store_get_object(object TSRMLS_CC);
 
+	if (by_ref && !(generator->execute_data->op_array->fn_flags & ZEND_ACC_RETURN_REFERENCE)) {
+		zend_error(E_ERROR, "You can only iterate a generator by-reference if it declared that it yields by-reference");
+	}
+
 	iterator = emalloc(sizeof(zend_generator_iterator));
 	iterator->intern.funcs = &zend_generator_iterator_functions;
 	iterator->intern.data = (void *) generator;