Fix: <interface> [extends <interface> [, <ineterface>]* ]

Zend/zend_compile.c

@@ -2452,7 +2452,7 @@ void zend_do_begin_class_declaration(znode *class_token, znode *class_name, znod
 	new_class_entry->line_start = zend_get_compiled_lineno(TSRMLS_C);
 	new_class_entry->ce_flags |= class_token->u.constant.value.lval;
 
-	if (parent_class_name->op_type != IS_UNUSED) {
+	if (parent_class_name && parent_class_name->op_type != IS_UNUSED) {
 		doing_inheritance = 1;
 	}
 
@@ -2542,10 +2542,6 @@ void zend_do_implements_interface(znode *interface_znode TSRMLS_DC)
 {
 	zend_op *opline = get_next_op(CG(active_op_array) TSRMLS_CC);
 
-	if (CG(active_class_entry)->ce_flags & ZEND_ACC_INTERFACE) {
-		zend_error(E_COMPILE_ERROR, "Interfaces cannot implement other classes/interfaces");
-	}
-
 	opline->opcode = ZEND_ADD_INTERFACE;
 	opline->op1 = CG(implementing_class);
 	opline->op2 = *interface_znode;

Zend/zend_language_parser.y

@@ -274,6 +274,12 @@ unticked_class_declaration_statement:
 			'{'
 				class_statement_list
 			'}' { zend_do_end_class_declaration(&$1, &$2 TSRMLS_CC); }
+	|	interface_entry T_STRING
+			{ zend_do_begin_class_declaration(&$1, &$2, NULL TSRMLS_CC); } 
+			interface_extends_list
+			'{'
+				class_statement_list
+			'}' { zend_do_end_class_declaration(&$1, &$2 TSRMLS_CC); }
 ;
 
 
@@ -281,7 +287,6 @@ class_entry_type:
 		T_CLASS			{  $$.u.constant.value.lval = 0; }
 	|	T_ABSTRACT T_CLASS { $$.u.constant.value.lval = ZEND_ACC_ABSTRACT_CLASS; }
 	|	T_FINAL T_CLASS { $$.u.constant.value.lval = ZEND_ACC_FINAL_CLASS; }
-	|	T_INTERFACE		{ $$.u.constant.value.lval = ZEND_ACC_INTERFACE; }
 ;
 
 extends_from:
@@ -289,6 +294,15 @@ extends_from:
 	|	T_EXTENDS fully_qualified_class_name	{ $$ = $2; }
 ;
 
+interface_entry:
+	T_INTERFACE		{ $$.u.constant.value.lval = ZEND_ACC_INTERFACE; }
+;
+
+interface_extends_list:
+		/* empty */
+	|	T_EXTENDS interface_list
+;
+
 implements_list:
 		/* empty */
 	|	T_IMPLEMENTS interface_list

tests/classes/interface_doubled.phpt

@@ -1,5 +1,5 @@
 --TEST--
-ZE2 An interface may both inherit and implement base interfaces
+ZE2 An interface extends base interfaces
 --SKIPIF--
 <?php if (version_compare(zend_version(), '2.0.0-dev', '<')) die('skip ZendEngine 2 needed'); ?>
 --FILE--
@@ -25,7 +25,7 @@ interface if_e {
 	abstract function f_d();
 }
 
-interface if_f extends if_e, if_a, if_b, if_c, if_d, if_e {
+interface if_f extends /*if_e,*/ if_a, if_b, if_c, if_d /*, if_e*/ {
 }
 
 class base {
@@ -154,6 +154,7 @@ echo $t->test('if_d');
 echo $t->test('if_e');
 
 ?>
+===DONE===
 --EXPECTF--
 class_a
 is_a(class_a, if_a) yes
@@ -196,4 +197,5 @@ is_a(class_g, if_a) yes
 is_a(class_g, if_b) yes
 is_a(class_g, if_c) yes
 is_a(class_g, if_d) yes
-is_a(class_g, if_e) yes
+is_a(class_g, if_e) no
+===DONE===