From 29dc6a7cee6ae3303b22e9c1d80c7bea9cb98e41 Mon Sep 17 00:00:00 2001
From: nielsdos <7771979+nielsdos@users.noreply.github.com>
Date: Wed, 7 Jun 2023 17:58:38 +0200
Subject: [PATCH] Allow final modifier when using a method from a trait

Fixes GH-11388.

Following https://wiki.php.net/rfc/horizontalreuse which introduced traits,
this should be allowed.
The implementation was refactored in 3f8c729. That commit is the first time
the "final" check appears AFAICT, but no reason was given for why. That
commit seems to have landed in 5.4.11 and the NEWS for that version doesn't
seem to mention something relevant to the behaviour change.
This patch removes the restriction of the final modifier.

Closes GH-11394.
---
 NEWS                               |  3 +++
 UPGRADING                          |  1 +
 Zend/tests/traits/language019.phpt |  5 ++++-
 Zend/tests/traits/language020.phpt | 21 +++++++++++++++++++++
 Zend/zend_compile.c                |  2 --
 5 files changed, 29 insertions(+), 3 deletions(-)
 create mode 100644 Zend/tests/traits/language020.phpt

diff --git a/NEWS b/NEWS
index 8cf60aeedf88..b86e31ec70fa 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,9 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 8.3.0alpha2
 
+- Core:
+  . Fix GH-11388 (Allow "final" modifier when importing a method from a trait).
+    (nielsdos)
 
 08 Jun 2023, PHP 8.3.0alpha1
 
diff --git a/UPGRADING b/UPGRADING
index 643c8d68ab90..1320b919206c 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -63,6 +63,7 @@ PHP 8.3 UPGRADE NOTES
   . Class, interface, trait, and enum constants now support type
     declarations. RFC: https://wiki.php.net/rfc/typed_class_constants
   . Closures created from magic methods can now accept named arguments.
+  . The final modifier may now be used when using a method from a trait.
 
 - Posix
   . posix_getrlimit() now takes an optional $res parameter to allow fetching a
diff --git a/Zend/tests/traits/language019.phpt b/Zend/tests/traits/language019.phpt
index 299f661db9b3..e64ec08909f5 100644
--- a/Zend/tests/traits/language019.phpt
+++ b/Zend/tests/traits/language019.phpt
@@ -10,6 +10,9 @@ class C1 {
         T1::foo as final;
     }
 }
+class C2 extends C1 {
+    public function foo() {}
+}
 ?>
 --EXPECTF--
-Fatal error: Cannot use "final" as method modifier in trait alias in %s on line %d
+Fatal error: Cannot override final method C1::foo() in %s on line %d
diff --git a/Zend/tests/traits/language020.phpt b/Zend/tests/traits/language020.phpt
new file mode 100644
index 000000000000..bbfa5c82652c
--- /dev/null
+++ b/Zend/tests/traits/language020.phpt
@@ -0,0 +1,21 @@
+--TEST--
+final alias - positive test variation
+--FILE--
+<?php
+trait T1 {
+    function foo() {
+        echo "Done\n";
+    }
+}
+class C1 {
+    use T1 {
+        T1::foo as final;
+    }
+}
+class C2 extends C1 {
+    public function bar() {}
+}
+(new C2)->foo();
+?>
+--EXPECT--
+Done
diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
index 5984206a8b13..b6a4840ab558 100644
--- a/Zend/zend_compile.c
+++ b/Zend/zend_compile.c
@@ -7727,8 +7727,6 @@ static void zend_check_trait_alias_modifiers(uint32_t attr) /* {{{ */
 		zend_error_noreturn(E_COMPILE_ERROR, "Cannot use \"static\" as method modifier in trait alias");
 	} else if (attr & ZEND_ACC_ABSTRACT) {
 		zend_error_noreturn(E_COMPILE_ERROR, "Cannot use \"abstract\" as method modifier in trait alias");
-	} else if (attr & ZEND_ACC_FINAL) {
-		zend_error_noreturn(E_COMPILE_ERROR, "Cannot use \"final\" as method modifier in trait alias");
 	}
 }
 /* }}} */