Make DirectoryIterator current() / key() return types tentative

Fixes GH-8192.

NEWS

@@ -23,6 +23,8 @@ PHP                                                                        NEWS
 - SPL:
   . Fixed bug GH-8121 (SplFileObject - seek and key with csv file inconsistent).
     (cmb)
+  . Fixed bug GH-8192 (Cannot override DirectoryIterator::current() without
+    return typehint in 8.1). (Nikita)
 
 - Standard:
   . Fixed bug GH-8048 (Force macOS to use statfs). (risner)

ext/spl/spl_directory.stub.php

@@ -123,10 +123,16 @@ class DirectoryIterator extends SplFileInfo implements SeekableIterator
     /** @tentative-return-type */
     public function valid(): bool {}
 
-    /** @return int */
+    /**
+     * @tentative-return-type
+     * @return int
+     */
     public function key(): mixed {} // TODO change return type to string
 
-    /** @return DirectoryIterator */
+    /**
+     * @tentative-return-type
+     * @return DirectoryIterator
+     */
     public function current(): mixed {} // TODO narrow return type
 
     /** @tentative-return-type */

ext/spl/spl_directory_arginfo.h

@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: eab71d8a7172dba2dac3c6fa97b2064c7a99191f */
+ * Stub hash: 3f2caf1c46760d8ef629ccb2e94ab0dba09f713b */
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_class_SplFileInfo___construct, 0, 0, 1)
 	ZEND_ARG_TYPE_INFO(0, filename, IS_STRING, 0)
@@ -102,7 +102,7 @@ ZEND_END_ARG_INFO()
 
 #define arginfo_class_DirectoryIterator_valid arginfo_class_SplFileInfo_isWritable
 
-ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_class_DirectoryIterator_key, 0, 0, IS_MIXED, 0)
+ZEND_BEGIN_ARG_WITH_TENTATIVE_RETURN_TYPE_INFO_EX(arginfo_class_DirectoryIterator_key, 0, 0, IS_MIXED, 0)
 ZEND_END_ARG_INFO()
 
 #define arginfo_class_DirectoryIterator_current arginfo_class_DirectoryIterator_key