Implement delyed early binding for classes without parents

Fixes GH-8846

Author: iluuu1994

Zend/zend_compile.c

@@ -8098,7 +8098,7 @@ static void zend_compile_class_decl(znode *result, zend_ast *ast, bool toplevel)
 		zend_add_literal_string(&key);
 
 		opline->opcode = ZEND_DECLARE_CLASS;
-		if (extends_ast && toplevel
+		if (toplevel
 			 && (CG(compiler_options) & ZEND_COMPILE_DELAYED_BINDING)
 				/* We currently don't early-bind classes that implement interfaces or use traits */
 			 && !ce->num_interfaces && !ce->num_traits

Zend/zend_inheritance.c

@@ -3184,6 +3184,10 @@ ZEND_API zend_class_entry *zend_do_link_class(zend_class_entry *ce, zend_string
 /* Check whether early binding is prevented due to unresolved types in inheritance checks. */
 static inheritance_status zend_can_early_bind(zend_class_entry *ce, zend_class_entry *parent_ce) /* {{{ */
 {
+	if (parent_ce == NULL) {
+		return INHERITANCE_SUCCESS;
+	}
+
 	zend_string *key;
 	zend_function *parent_func;
 	zend_property_info *parent_info;
@@ -3278,7 +3282,9 @@ ZEND_API zend_class_entry *zend_try_early_bind(zend_class_entry *ce, zend_class_
 	zend_class_entry *orig_linking_class;
 	uint32_t is_cacheable = ce->ce_flags & ZEND_ACC_IMMUTABLE;
 
-	UPDATE_IS_CACHEABLE(parent_ce);
+	if (parent_ce) {
+		UPDATE_IS_CACHEABLE(parent_ce);
+	}
 	if (is_cacheable) {
 		if (zend_inheritance_cache_get && zend_inheritance_cache_add) {
 			zend_class_entry *ret = zend_inheritance_cache_get(ce, parent_ce, NULL);
@@ -3321,7 +3327,9 @@ ZEND_API zend_class_entry *zend_try_early_bind(zend_class_entry *ce, zend_class_
 				zend_begin_record_errors();
 			}
 
-			zend_do_inheritance_ex(ce, parent_ce, status == INHERITANCE_SUCCESS);
+			if (parent_ce) {
+				zend_do_inheritance_ex(ce, parent_ce, status == INHERITANCE_SUCCESS);
+			}
 			if (parent_ce && parent_ce->num_interfaces) {
 				zend_do_inherit_interfaces(ce, parent_ce);
 			}

Zend/zend_vm_def.h

@@ -7791,7 +7791,7 @@ ZEND_VM_HANDLER(144, ZEND_DECLARE_CLASS, CONST, ANY)
 	ZEND_VM_NEXT_OPCODE_CHECK_EXCEPTION();
 }
 
-ZEND_VM_HANDLER(145, ZEND_DECLARE_CLASS_DELAYED, CONST, CONST)
+ZEND_VM_HANDLER(145, ZEND_DECLARE_CLASS_DELAYED, CONST, CONST|UNUSED)
 {
 	USE_OPLINE
 
@@ -7801,7 +7801,7 @@ ZEND_VM_HANDLER(145, ZEND_DECLARE_CLASS_DELAYED, CONST, CONST)
 		zval *zv = zend_hash_find_known_hash(EG(class_table), Z_STR_P(lcname + 1));
 		if (zv) {
 			SAVE_OPLINE();
-			ce = zend_bind_class_in_slot(zv, lcname, Z_STR_P(RT_CONSTANT(opline, opline->op2)));
+			ce = zend_bind_class_in_slot(zv, lcname, OP2_TYPE == IS_CONST ? Z_STR_P(RT_CONSTANT(opline, opline->op2)) : NULL);
 			if (!ce) {
 				HANDLE_EXCEPTION();
 			}