Don't enforce LSP if prototype method is private

Fixes bug #72496.

Author: pmmaga

NEWS

@@ -5,6 +5,8 @@ PHP                                                                        NEWS
 - Core:
   . Fix bug #71936 (Segmentation fault destroying HTTP_RAW_POST_DATA).
     (mike dot laspina at gmail dot com, Remi)
+  . Fix bug #72496 (Cannot declare public method with signature incompatible
+    with parent private method). (Pedro Magalhães)
 
 - bz2:
   . Fix bug #72447 (Type Confusion in php_bz2_filter_create()). (gogil at 

Zend/tests/bug72496.phpt

@@ -0,0 +1,43 @@
+--TEST--
+Bug #72496 (declare public method with signature incompatible with parent private method should not throw a warning)
+--FILE--
+<?php
+class Foo
+{
+    private function getFoo()
+    {
+        return 'Foo';
+    }
+
+    private function getBar()
+    {
+        return 'Bar';
+    }
+
+    private function getBaz()
+    {
+        return 'Baz';
+    }
+}
+
+class Bar extends Foo
+{
+    public function getFoo($extraArgument)
+    {
+        return $extraArgument;
+    }
+
+    protected function getBar($extraArgument)
+    {
+        return $extraArgument;
+    }
+
+    private function getBaz($extraArgument)
+    {
+        return $extraArgument;
+    }
+}
+
+echo "OK\n";
+--EXPECT--
+OK

Zend/zend_compile.c

@@ -3252,8 +3252,8 @@ static zend_bool zend_do_perform_implementation_check(const zend_function *fe, c
 		return 1;
 	}
 
-	/* If both methods are private do not enforce a signature */
-    if ((fe->common.fn_flags & ZEND_ACC_PRIVATE) && (proto->common.fn_flags & ZEND_ACC_PRIVATE)) {
+	/* If the prototype method is private do not enforce a signature */
+	if (proto->common.fn_flags & ZEND_ACC_PRIVATE) {
 		return 1;
 	}