Fixed covariance of return-by-ref constraints

diff --git a/Zend/tests/objects_032.phpt b/Zend/tests/objects_032.phpt
new file mode 100644 (file)
index 0000000..e5e3eca
--- /dev/null
+++ b/Zend/tests/objects_032.phpt
@@ -0,0 +1,40 @@
+--TEST--
+Covariant return-by-ref constraints
+--FILE--
+<?php
+
+class A implements ArrayAccess {
+    public $foo = array();
+
+    public function &offsetGet($n) {
+        return $this->foo[$n];
+    }
+
+    public function offsetSet($n, $v) {
+    }
+    public function offsetUnset($n) {
+    }
+    public function offsetExists($n) {
+    }
+}
+
+$a = new A;
+
+$a['foo']['bar'] = 2;
+
+var_dump($a);
+
+?>
+==DONE==
+--EXPECTF--
+object(A)#1 (1) {
+  ["foo"]=>
+  array(1) {
+    ["foo"]=>
+    array(1) {
+      ["bar"]=>
+      int(2)
+    }
+  }
+}
+==DONE==

diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
index 08b70b226724e78f384f1018b481f534e4c0c98e..c49dce6fcb76c0ae4d3f49afe17e5a2ab7295f0f 100644 (file)
--- a/Zend/zend_compile.c
+++ b/Zend/zend_compile.c
@@ -2956,8 +2956,9 @@ static zend_bool zend_do_perform_implementation_check(const zend_function *fe, c
                return 0;
        }
 
-       if ((fe->common.fn_flags & ZEND_ACC_RETURN_REFERENCE) !=
-           (proto->common.fn_flags & ZEND_ACC_RETURN_REFERENCE)) {
+       /* by-ref constraints on return values are covariant */
+       if ((proto->common.fn_flags & ZEND_ACC_RETURN_REFERENCE)
+               && !(fe->common.fn_flags & ZEND_ACC_RETURN_REFERENCE)) {
                return 0;
        }
 
@@ -2981,6 +2982,8 @@ static zend_bool zend_do_perform_implementation_check(const zend_function *fe, c
                        /* Incompatible type hint */
                        return 0;
                }
+
+               /* by-ref constraints on arguments are invariant */
                if (fe->common.arg_info[i].pass_by_reference != proto->common.arg_info[i].pass_by_reference) {
                        return 0;
                }