Don't load classes of an intersection if parent has object

Refactor a bit the handling of iterable as a by product.

Author: Girgias

Zend/tests/type_declarations/intersection_types/variance/invalid4.phpt renamed to Zend/tests/type_declarations/intersection_types/variance/valid9.phpt

@@ -13,5 +13,5 @@ class Test2 extends Test {
 
 ?>
 ===DONE===
---EXPECTF--
-Fatal error: Could not check compatibility between Test2::method(): X&Y and Test::method(): object, because class X is not available in %s on line %d
+--EXPECT--
+===DONE===

Zend/zend_inheritance.c

@@ -606,24 +606,31 @@ static inheritance_status zend_perform_covariant_type_check(
 	bool have_unresolved = false;
 
 	if (ZEND_TYPE_IS_INTERSECTION(fe_type)) {
-		if (proto_type_mask & (MAY_BE_OBJECT|MAY_BE_ITERABLE)) {
-			bool any_class = (proto_type_mask & MAY_BE_OBJECT) != 0;
+		/* As an intersection type can only be composed of class types (checked at compile stage),
+		 * it is trivially covariant to the object type.
+		 * Handle this case separately to ensure it never requires class loading. */
+		if (proto_type_mask & MAY_BE_OBJECT) {
+			return INHERITANCE_SUCCESS;
+		}
+
+		// TODO: Make "iterable" an alias of "array|Traversable" instead,
+		// so this special cases will be handled automatically.
+		if (proto_type_mask & MAY_BE_ITERABLE) {
 			ZEND_TYPE_FOREACH(fe_type, single_type) {
 				zend_class_entry *fe_ce;
 				zend_string *fe_class_name = get_class_from_type(&fe_ce, fe_scope, *single_type);
-				if (!fe_class_name) {
-					continue;
-				}
+
+				ZEND_ASSERT(fe_class_name);
 				if (!fe_ce) {
 					fe_ce = lookup_class(fe_scope, fe_class_name);
 				}
-				if (fe_ce) {
-					if (any_class || unlinked_instanceof(fe_ce, zend_ce_traversable)) {
-						track_class_dependency(fe_ce, fe_class_name);
-						return INHERITANCE_SUCCESS;
-					}
-				} else {
+				if (!fe_ce) {
 					have_unresolved = true;
+					continue;
+				}
+				if (unlinked_instanceof(fe_ce, zend_ce_traversable)) {
+					track_class_dependency(fe_ce, fe_class_name);
+					return INHERITANCE_SUCCESS;
 				}
 			} ZEND_TYPE_FOREACH_END();
 		}