Remove ZEND_ACC_IMPLEMENT_INTERFACES flag

This is equivalent to checking ce->num_interfaces. The only subtle
moment is during inheritance, where num_interface may change when
parent interfaces are inherited. The check in zend_do_link_class
thus uses "interfaces", not "ce->num_interfaces".

Author: nikic

Zend/zend_compile.c

@@ -6523,7 +6523,6 @@ void zend_compile_implements(zend_ast *ast) /* {{{ */
 		interface_names[i].lc_name = zend_string_tolower(interface_names[i].name);
 	}
 
-	ce->ce_flags |= ZEND_ACC_IMPLEMENT_INTERFACES;
 	ce->num_interfaces = list->children;
 	ce->interface_names = interface_names;
 }
@@ -6664,7 +6663,7 @@ zend_op *zend_compile_class_decl(zend_ast *ast, zend_bool toplevel) /* {{{ */
 
 	if (toplevel
 		/* We currently don't early-bind classes that implement interfaces or use traits */
-	 && !(ce->ce_flags & ZEND_ACC_IMPLEMENT_INTERFACES) && !ce->num_traits
+	 && !ce->num_interfaces && !ce->num_traits
 	 && !(CG(compiler_options) & ZEND_COMPILE_PRELOAD)) {
 		if (extends_ast) {
 			zend_class_entry *parent_ce = zend_lookup_class_ex(
@@ -6725,7 +6724,7 @@ zend_op *zend_compile_class_decl(zend_ast *ast, zend_bool toplevel) /* {{{ */
 		if (extends_ast && toplevel
 			 && (CG(compiler_options) & ZEND_COMPILE_DELAYED_BINDING)
 				/* We currently don't early-bind classes that implement interfaces or use traits */
-			 && !(ce->ce_flags & ZEND_ACC_IMPLEMENT_INTERFACES) && !ce->num_traits
+			 && !ce->num_interfaces && !ce->num_traits
 		) {
 			CG(active_op_array)->fn_flags |= ZEND_ACC_EARLY_BINDING;
 			opline->opcode = ZEND_DECLARE_CLASS_DELAYED;

Zend/zend_compile.h

@@ -229,7 +229,7 @@ typedef struct _zend_oparray_context {
 /* op_array or class is preloaded                         |     |     |     */
 #define ZEND_ACC_PRELOADED               (1 << 10) /*  X  |  X  |     |     */
 /*                                                        |     |     |     */
-/* Class Flags (unused: 13, 15, 24...)                    |     |     |     */
+/* Class Flags (unused: 13, 14, 15, 24...)                |     |     |     */
 /* ===========                                            |     |     |     */
 /*                                                        |     |     |     */
 /* Special class types                                    |     |     |     */
@@ -251,9 +251,6 @@ typedef struct _zend_oparray_context {
 /* Class constants updated                                |     |     |     */
 #define ZEND_ACC_CONSTANTS_UPDATED       (1 << 12) /*  X  |     |     |     */
 /*                                                        |     |     |     */
-/* Class implements interface(s)                          |     |     |     */
-#define ZEND_ACC_IMPLEMENT_INTERFACES    (1 << 14) /*  X  |     |     |     */
-/*                                                        |     |     |     */
 /* User class has methods with static variables           |     |     |     */
 #define ZEND_HAS_STATIC_IN_METHODS       (1 << 16) /*  X  |     |     |     */
 /*                                                        |     |     |     */

Zend/zend_inheritance.c

@@ -1161,7 +1161,7 @@ ZEND_API void zend_do_inheritance_ex(zend_class_entry *ce, zend_class_entry *par
 
 	/* Inherit interfaces */
 	if (parent_ce->num_interfaces) {
-		if (!(ce->ce_flags & ZEND_ACC_IMPLEMENT_INTERFACES)) {
+		if (!ce->num_interfaces) {
 			zend_do_inherit_interfaces(ce, parent_ce);
 		} else {
 			uint32_t i;
@@ -2463,7 +2463,7 @@ ZEND_API int zend_do_link_class(zend_class_entry *ce, zend_string *lc_parent_nam
 	if (ce->num_traits) {
 		zend_do_bind_traits(ce);
 	}
-	if (ce->ce_flags & ZEND_ACC_IMPLEMENT_INTERFACES) {
+	if (interfaces) {
 		zend_do_implement_interfaces(ce, interfaces);
 	}
 	if ((ce->ce_flags & (ZEND_ACC_IMPLICIT_ABSTRACT_CLASS|ZEND_ACC_INTERFACE|ZEND_ACC_TRAIT|ZEND_ACC_EXPLICIT_ABSTRACT_CLASS)) == ZEND_ACC_IMPLICIT_ABSTRACT_CLASS) {