PHP Wiki

bound_erased_generic_types - ''getGenericArgumentsForParentInterface()'' returns ''list''

azjezz (azjezz@undisclosed.example.com) — 2026-05-14T21:18:57+00:00

2026/05/13 19:29		current
Line 1:		Line 1:
	====== PHP RFC: Bound-Erased Generic Types ======		====== PHP RFC: Bound-Erased Generic Types ======
-	* Version: 0.20	+	* Version: 0.21
	* Date: 2026-05-08		* Date: 2026-05-08
	* Author: Seifeddine Gmati, azjezz@carthage.software		* Author: Seifeddine Gmati, azjezz@carthage.software
Line 988:		Line 988:

	/**		/**
-	* @return list<ReflectionType>	+	* Every generic argument set this class supplies for the named ancestor
		+	* interface, in inheritance traversal order. The outer list contains one
		+	* entry per binding: a class may bind the same generic interface multiple
		+	* times either directly (''implements Foo<int>, Foo<string>'') or
		+	* transitively through different inheritance paths. Each inner list holds
		+	* the type arguments for that binding in source order. Returns an empty
		+	* outer list when no generic bindings to the ancestor exist.
		+	*
		+	* @return list<list<ReflectionType>>
	* @throws ReflectionException if $name is not an ancestor interface		* @throws ReflectionException if $name is not an ancestor interface
	*/		*/
Line 1024:		Line 1032:
	// $params[0]->hasBound() === false		// $params[0]->hasBound() === false
	// $params[0]->getVariance() === ReflectionGenericVariance::Invariant		// $params[0]->getVariance() === ReflectionGenericVariance::Invariant
		+
		+	interface Foo<T> {}
		+	class Dup implements Foo<string>, Foo<int> {}
		+
		+	$bindings = (new ReflectionClass(Dup::class))->getGenericArgumentsForParentInterface('Foo');
		+	// count($bindings) === 2
		+	// $bindings[0][0]->getName() === "string"
		+	// $bindings[1][0]->getName() === "int"
	</PHP>		</PHP>

Line 1030:		Line 1046:
	''getDefault()'' throw when there is no bound or default - they are		''getDefault()'' throw when there is no bound or default - they are
	escape-hatch accessors paired with ''hasBound()'' and ''hasDefault()''.		escape-hatch accessors paired with ''hasBound()'' and ''hasDefault()''.
		+
		+	''getGenericArgumentsForParentInterface()'' returns a list of bindings -
		+	one inner list per generic argument set the class supplies for the
		+	ancestor. The plural shape is forced by the language: a class may bind
		+	the same interface more than once, either directly (as in ''Dup'' above)
		+	or transitively through two different inheritance paths (the diamond
		+	shape covered in [[#Diamond inheritance\|Diamond inheritance]]). A
		+	single-binding class returns a single-entry outer list. The parent-class
		+	and used-trait lookups stay singular because PHP allows at most one
		+	''extends'' clause and at most one ''use'' of any given trait.

	==== Diamond inheritance ====		==== Diamond inheritance ====
Line 2113:		Line 2139:
	* 2026-05-13: Promoted the enforcement framing higher; added a turbofish-optional paragraph; led the Turbofish section with optionality (v0.19).		* 2026-05-13: Promoted the enforcement framing higher; added a turbofish-optional paragraph; led the Turbofish section with optionality (v0.19).
	* 2026-05-13: ''ReflectionGenericVariance'' is now a unit enum (v0.20).		* 2026-05-13: ''ReflectionGenericVariance'' is now a unit enum (v0.20).
		+	* 2026-05-14: ''getGenericArgumentsForParentInterface()'' returns ''list<list<ReflectionType>>'' (v0.21).

deprecations_php_8_6

lamentxu (lamentxu@undisclosed.example.com) — 2026-05-14T07:53:48+00:00

2026/05/14 07:53		current
Line 31:		Line 31:
	* Deprecate <php>ArrayIterator</php> methods that inherit <php>ArrayObject</php> implementation		* Deprecate <php>ArrayIterator</php> methods that inherit <php>ArrayObject</php> implementation
	* Deprecate <php>metaphone</php> function		* Deprecate <php>metaphone</php> function
-	* Deprecate changing by-reference return modifier via inheritance	+	* Deprecate changing by-reference return modifier via inheritance
-	* Deprecate dechunk php filter	+

	===== Proposal =====		===== Proposal =====

rfc

eskyuu (eskyuu@undisclosed.example.com) — 2026-05-13T14:05:07+00:00

2026/05/13 14:05		current
Line 95:		Line 95:

	===== Accepted =====		===== Accepted =====
-
-	* [[rfc:snmp_improvements_2026\|SNMP Improvements]] (Created 2026-03-30; Accepted 2026-05-08)

	==== Process and Policy ====		==== Process and Policy ====
Line 136:		Line 134:
	==== Pending Implementation / Landing ====		==== Pending Implementation / Landing ====

		+	* [[rfc:snmp_improvements_2026\|SNMP Improvements]] (Created 2026-03-30; Accepted 2026-05-08)
	* [[rfc:tls_session_resumption_api\|TLS Session Resumption Support for Streams]] (Created 2025-12-22; discussion started 2025-12-22)		* [[rfc:tls_session_resumption_api\|TLS Session Resumption Support for Streams]] (Created 2025-12-22; discussion started 2025-12-22)
	* [[rfc:pack-unpack-float-endianness-modifier\|Add pack()/unpack() endianness modifiers for floating-point numbers]] (Created 2026-01-30)		* [[rfc:pack-unpack-float-endianness-modifier\|Add pack()/unpack() endianness modifiers for floating-point numbers]] (Created 2026-01-30)

snmp_improvements_2026 - Close voting and mark accepted

eskyuu (eskyuu@undisclosed.example.com) — 2026-05-13T14:03:42+00:00

2026/04/22 13:33		current
Line 3:		Line 3:
	* Date: 2026-03-27		* Date: 2026-03-27
	* Author: Steven Wilton, swilton@fluentit.au		* Author: Steven Wilton, swilton@fluentit.au
-	* Status: Voting	+	* Status: Accepted
	* Implementation:		* Implementation:
	* https://github.com/php/php-src/pull/21451 (Increase security protocol options)		* https://github.com/php/php-src/pull/21451 (Increase security protocol options)
Line 126:		Line 126:
	Primary Vote requiring a 2/3 majority to accept the RFC:		Primary Vote requiring a 2/3 majority to accept the RFC:

-	<doodle title="Increase the number of SNMPv3 security protocols supported" voteType="single" closed="false" closeon="2026-05-08T00:00:00Z">	+	<doodle title="Increase the number of SNMPv3 security protocols supported" voteType="single" closed="true" closeon="2026-05-08T00:00:00Z">
	* Yes		* Yes
	* No		* No
Line 132:		Line 132:
	</doodle>		</doodle>

-	<doodle title="Allow the SNMP MIB to be reset" voteType="single" closed="false" closeon="2026-05-08T00:00:00Z">	+	<doodle title="Allow the SNMP MIB to be reset" voteType="single" closed="true" closeon="2026-05-08T00:00:00Z">
	* Yes		* Yes
	* No		* No
Line 138:		Line 138:
	</doodle>		</doodle>

-	<doodle title="Implement more MIB parsing and value output controls" voteType="single" closed="false" closeon="2026-05-08T00:00:00Z">	+	<doodle title="Implement more MIB parsing and value output controls" voteType="single" closed="true" closeon="2026-05-08T00:00:00Z">
	* Yes		* Yes
	* No		* No

debugable-enums - implementation merged

daniels (daniels@undisclosed.example.com) — 2026-05-10T17:08:18+00:00

2026/04/18 00:33		current
Line 3:		Line 3:
	* Date: 2026-03-12		* Date: 2026-03-12
	* Author: Daniel Scherzer, daniel.e.scherzer@gmail.com		* Author: Daniel Scherzer, daniel.e.scherzer@gmail.com
-	* Status: Pending implementation/landing	+	* Status: Implemented (in PHP 8.6)
	* Implementation: https://github.com/php/php-src/pull/21425		* Implementation: https://github.com/php/php-src/pull/21425
	* Discussion thread: https://news-web.php.net/php.internals/130303		* Discussion thread: https://news-web.php.net/php.internals/130303

friends - under discussion

daniels (daniels@undisclosed.example.com) — 2026-05-10T16:35:40+00:00

2026/05/08 21:35		current
Line 3:		Line 3:
	* Date: 2026-05-04		* Date: 2026-05-04
	* Author: Daniel Scherzer, daniel.e.scherzer@gmail.com		* Author: Daniel Scherzer, daniel.e.scherzer@gmail.com
-	* Status: Draft	+	* Status: Under discussion
	* Implementation: https://github.com/php/php-src/pull/21937		* Implementation: https://github.com/php/php-src/pull/21937
		+	* Discussion thread: https://news-web.php.net/php.internals/130815

	This RFC proposes adding support for friendship in PHP, allowing classes to specify other classes as friends. Those friends would then be able to access protected and private properties, constants, and methods of the declaring class.		This RFC proposes adding support for friendship in PHP, allowing classes to specify other classes as friends. Those friends would then be able to access protected and private properties, constants, and methods of the declaring class.

template - add placeholder for discussion thread at the top

daniels (daniels@undisclosed.example.com) — 2026-05-10T16:29:54+00:00

2026/01/16 11:08		current
Line 5:		Line 5:
	* Status: Draft (Later in the RFC process "Under Discussion", "Voting", and finally "Accepted", "Declined" or "Implemented")		* Status: Draft (Later in the RFC process "Under Discussion", "Voting", and finally "Accepted", "Declined" or "Implemented")
	* Implementation: https://github.com/...		* Implementation: https://github.com/...
		+	* Discussion thread:

	This is the suggested template for PHP Request for Comments (RFCs). Change this template to suit your RFC. Not all RFCs need all the sections below.		This is the suggested template for PHP Request for Comments (RFCs). Change this template to suit your RFC. Not all RFCs need all the sections below.

deprecated_interfaces - created

daniels (daniels@undisclosed.example.com) — 2026-05-10T16:18:37+00:00

2026/05/15 06:33	current
Line 1:	Line 1:
	+	====== PHP RFC: #[\Deprecated] for interfaces ======
	+	* Version: 0.1
	+	* Date: 2026-05-10
	+	* Author: Daniel Scherzer, daniel.e.scherzer@gmail.com
	+	* Status: Draft
	+	* Implementation: https://github.com/php/php-src/pull/21998
	+	* Discussion thread:

	+	===== Introduction =====
	+
	+	The <php>#[\Deprecated]</php> attribute was introduced in PHP 8.4 ([[rfc:deprecated_attribute]]) and could be used to emit deprecation warnings when calling a function (or class method), or when accessing a class constant (or enum case). Starting in 8.5, deprecation warnings could also be emitted when accessing a global constant ([[rfc:attributes-on-constants]]) or when <php>use</php>ing a trait ([[rfc:deprecated_traits]]). This RFC proposes to add support for emitting deprecation warnings when an interface is extended or implemented.
	+
	+	<PHP>
	+	<?php
	+
	+	#[\Deprecated]
	+	trait DemoInterface {}
	+
	+	class DemoClass implements DemoInterface {}
	+
	+	// Reports:
	+	// Deprecated: Interface DemoInterface implemented by DemoClass is deprecated in %s on line %d
	+	?>
	+	</PHP>
	+
	+	===== Proposal =====
	+	The <php>#[\Deprecated]</php> attribute will be allowed on interfaces. The existing target validation when applied to classes or enums is maintained.
	+
	+	When the interfaces that a class implements are loaded, any deprecated interfaces emit a deprecation message; these can be converted to an exception via a user error handler, and an uncaught exception will be treated the same as trying to implement a non-interface in terms of registration behavior. The same applies to interfaces extending other interfaces if those other interfaces are marked as deprecated.
	+
	+	Interfaces only emit deprecation warnings when //directly// extended or implemented, implementing child interfaces or extending implementing classes does not result in extra errors. See the comparison with existing tools below.
	+
	+	==== Examples ====
	+
	+	Simple example:
	+	<PHP>
	+	<?php
	+
	+	#[\Deprecated]
	+	trait DemoInterface {}
	+
	+	class DemoClass implements DemoInterface {}
	+
	+	// Reports:
	+	// Deprecated: Interface DemoInterface implemented by DemoClass is deprecated in %s on line %d
	+	?>
	+	</PHP>
	+
	+	With an exception:
	+	<PHP>
	+	<?php
	+
	+	function my_error_handler(int $errno, string $errstr, ?string $errfile = null, ?int $errline = null) {
	+	throw new \ErrorException($errstr, 0, $errno, $errfile, $errline);
	+	}
	+
	+	set_error_handler('my_error_handler');
	+
	+	#[\Deprecated]
	+	interface DemoInterface {}
	+
	+	class DemoClass implements DemoInterface {}
	+
	+	// Reports:
	+	// Fatal error: Uncaught ErrorException: Interface DemoInterface implemented by DemoClass is deprecated in %s:%d
	+
	+	?>
	+	</PHP>
	+
	+	==== Tool comparison ====
	+
	+	Given the following code:
	+	<PHP>
	+	<?php
	+
	+	/**
	+	* @deprecated
	+	*/
	+	interface BaseInterface {}
	+
	+	interface ChildInterface extends BaseInterface {}
	+
	+	class ImplementsBase implements BaseInterface {}
	+
	+	class ImplementsBoth implements BaseInterface, ChildInterface {}
	+
	+	class ImplementsChild implements ChildInterface {}
	+
	+	class ExtendsBaseImplementor extends ImplementsBase {}
	+
	+	?>
	+	</PHP>
	+
	+	existing static analysis tools emit warnings for different sets of declarations. The behavior of the tools and the engine is as follows, where "yes" means a warning is emitted (with the engine behavior coming from using <php>#[\Deprecated]</php> rather than a comment):
	+
	+	^ Declaration ^ Phan ^ PHPStan ^ Mago ^ Psalm ^ Engine ^
	+	\| <php>interface ChildInterface... </php> \| yes \| yes \| yes \| no \| yes \|
	+	\| <php>class ImlementsBase... </php> \| yes \| yes \| no \| yes \| yes \|
	+	\| <php>class ImlementsBoth... </php> \| yes \| yes \| no \| yes \| yes \|
	+	\| <php>class ImlementsChild... </php> \| no \| no \| no \| yes \| no \|
	+	\| <php>class ExtendsBaseImplementor...</php> \| no \| no \| no \| yes \| no \|
	+
	+
	+	PHPStan is as of the version on the playground (https://phpstan.org/try) on 2026.05.10, Psalm is as of commit 5c1c31c which was on its playground (https://psalm.dev/) on the same date. Phan is as of version 6.0.5, Mago is as of version 1.26.0.
	+
	+	===== Backward Incompatible Changes =====
	+	None
	+
	+	===== Proposed PHP Version(s) =====
	+	Next PHP (8.6)
	+
	+	===== RFC Impact =====
	+	==== To the Ecosystem ====
	+	IDEs and static analyzers will likely want to update to surface deprecation messages when an interface is extended or implemented without waiting for PHP to emit the errors.
	+
	+	==== To Existing Extensions ====
	+	This lays the engine support for deprecating PHP-provided interfaces, but none are currently marked as deprecated.
	+
	+	==== To SAPIs ====
	+	No impact other than deprecations being emitted when a deprecated interface is used.
	+
	+	===== Open Issues =====
	+	Make sure there are no open issues when the vote starts!
	+
	+	===== Future Scope =====
	+	Other places that <php>#[\Deprecated]</php> could eventually be supported include
	+
	+	* extending a class
	+	* overriding a method
	+	* accessing a property
	+
	+	But the support for deprecating the use of a interface is pretty straightforward and there isn't room for future improvements within the context of deprecating interface.
	+
	+
	+	===== Voting Choices =====
	+	<doodle title="Add support for #[\Deprecated] on interfaces?" voteType="single" closed="true" closeon="2025-08-07T23:59:59Z" auth="daniels">
	+	* Yes
	+	* No
	+	</doodle>
	+
	+	===== Patches and Tests =====
	+	https://github.com/php/php-src/pull/21998
	+
	+	===== Implementation =====
	+	After the RFC is implemented, this section should contain:
	+	- the version(s) it was merged into
	+	- a link to the git commit(s)
	+	- a link to the PHP manual entry for the feature
	+
	+	===== References =====
	+
	+	* [[rfc:deprecated_attribute]]
	+	* [[rfc:attributes-on-constants]]
	+	* [[rfc:deprecated_traits]]
	+
	+	===== Rejected Features =====
	+	Keep this updated with features that were discussed on the mail lists.
	+
	+	===== Changelog =====
	+	If there are major changes to the initial proposal, please include a short summary with a date or a link to the mailing list announcement here, as not everyone has access to the wikis' version history.
	+
	+	* v0.1: created

limit-maximum-number-of-filter-chains - Under discussion

sjoerd (sjoerd@undisclosed.example.com) — 2026-05-09T13:18:02+00:00

2026/05/09 13:12		current
Line 1:		Line 1:
	====== PHP RFC: Limit maximum number of filter chains ======		====== PHP RFC: Limit maximum number of filter chains ======

-	* Version: 0.3	+	* Version: 1.0
	* Date: 2026-05-05		* Date: 2026-05-05
	* Author: Sjoerd Langkemper <sjoerd-php@linuxonly.nl>		* Author: Sjoerd Langkemper <sjoerd-php@linuxonly.nl>
-	* Status: Draft	+	* Status: Under discussion
	* Implementation: https://github.com/php/php-src/pull/16699		* Implementation: https://github.com/php/php-src/pull/16699

Line 143:		Line 143:
	* 0.2 2026-05-08 Added iconv vulns, dechunk behaviour change		* 0.2 2026-05-08 Added iconv vulns, dechunk behaviour change
	* 0.3 2026-05-09 Added "Number of filters" section		* 0.3 2026-05-09 Added "Number of filters" section
		+	* 1.0 2026-05-09 Under discussion

scope-functions - Improve structure of examples and restrictions

edorian (edorian@undisclosed.example.com) — 2026-05-08T22:57:17+00:00

2026/05/08 22:27		current
Line 227:		Line 227:

	===== Restrictions =====		===== Restrictions =====
		+
		+	==== Closure operations ====

	* ''static fn() {}'': ''$this'' is already shared, a static scope function would be incoherent.		* ''static fn() {}'': ''$this'' is already shared, a static scope function would be incoherent.
Line 237:		Line 239:
	Parse error: syntax error, unexpected token "use", expecting "{" in %s on line %d		Parse error: syntax error, unexpected token "use", expecting "{" in %s on line %d
	</code>		</code>
-
-	A scope function cannot leave the lifetime of its defining function as its variables live in the parent.
-
-	This requires some constraints to be enforced:

	* Recursion: Recursive calls will raise an ''Error''.		* Recursion: Recursive calls will raise an ''Error''.
Line 259:		Line 257:
	$fn = fn() { print $this->call(); };		$fn = fn() { print $this->call(); };
	(Closure::bind($fn, $this, "Ancestor"))(); // Allowed, prints "parent"		(Closure::bind($fn, $this, "Ancestor"))(); // Allowed, prints "parent"
-	Closure::bind($fn, null); // Error: Cannot rebind $this of a scope function	+	Closure::bind($fn, null); // Cannot rebind $this of a scope function
	}		}
	}		}
	</code>		</code>

-	* Re-evaluation: The same scope function declaration (same source code location) invalidates the previous instance. Should it still be called, an error is raised.	+	==== Lifetime ====
-	Any scope closure is only allocated a single slot, preventing recursion and double declaration. There are two choices: guaranteeing uniqueness (returning the active Closure again) or invalidating the previous Closure. We chose the second option to avoid the misconception that scope functions would capture the current variables. E.g. in foreach loops, it will always print the current active value and never the value at declaration time.	+

-	<code php>	+	A scope function cannot leave the lifetime of its defining function as its variables live in the parent.
-	$closures = [];	+
-	for ($i = 0; $i < 3; $i++) {	+
-	$closures[] = fn() { return $i; };	+
-	}	+
-	var_dump($closures[2]()); // int(3)	+
-		+
-	$closures[0](); // Error: Cannot call scope function: defining scope has exited	+
-	</code>	+
-		+
-	* Generators & Fibers: ''yield'', ''yield from'', and ''Fiber::suspend()'' inside a scope function work normally. If the parent exits while the coroutine is suspended inside an active scope function call, the coroutine is unwound.	+
-		+
-	==== Outliving the parent ====	+

	A scope function may be invoked any number of times while that frame is alive. Once a functions exits, via ''return'', an exception, or through a generator/fiber being closed the closure is invalidated.		A scope function may be invoked any number of times while that frame is alive. Once a functions exits, via ''return'', an exception, or through a generator/fiber being closed the closure is invalidated.
Line 299:		Line 284:

	Should the thrown error be caught and the stored scope Closure be accessed afterwards, the Closure will throw when called. The eager error is intended as a debugging aid. Every other operation on the Closure remains valid".		Should the thrown error be caught and the stored scope Closure be accessed afterwards, the Closure will throw when called. The eager error is intended as a debugging aid. Every other operation on the Closure remains valid".
		+
		+	* Generators & Fibers: ''yield'', ''yield from'', and ''Fiber::suspend()'' inside a scope function work normally. If the parent exits while the coroutine is suspended inside an active scope function call, the coroutine is unwound.

	=== Suspended callers ===		=== Suspended callers ===
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	require 'include.php';		require 'include.php';
	var_dump(isset($f)); // bool(false)		var_dump(isset($f)); // bool(false)
		+	</code>
		+
		+	==== Re-evaluation ====
		+
		+	The same scope function declaration (same source code location) invalidates the previous instance. Should it still be called, an error is raised.
		+
		+	Any scope closure is only allocated a single slot, preventing recursion and double declaration. There are two choices: guaranteeing uniqueness (returning the active Closure again) or invalidating the previous Closure. We chose the second option to avoid the misconception that scope functions would capture the current variables. E.g. in foreach loops, it will always print the current active value and never the value at declaration time.
		+
		+	<code php>
		+	$closures = [];
		+	for ($i = 0; $i < 3; $i++) {
		+	$closures[] = fn() { return $i; };
		+	}
		+	var_dump($closures[2]()); // int(3)
		+
		+	$closures[0](); // Error: Cannot call scope function: defining scope has exited
	</code>		</code>

Line 375:		Line 378:
	* [[https://wiki.php.net/rfc/closure-optimizations\|Closure optimizations]]		* [[https://wiki.php.net/rfc/closure-optimizations\|Closure optimizations]]
	* [[https://wiki.php.net/rfc/auto-capture-closure\|(Declined) Short Closures 2.0 RFC]]		* [[https://wiki.php.net/rfc/auto-capture-closure\|(Declined) Short Closures 2.0 RFC]]
		+

deprecate-return-value-from-construct - Add discussion link

timwolla (timwolla@undisclosed.example.com) — 2026-05-08T10:34:40+00:00

2026/05/08 08:44		current
Line 115:		Line 115:
	* Mailing List Discussion of making <php>new</php> emit an error if a value is returned: https://news-web.php.net/php.internals/129980		* Mailing List Discussion of making <php>new</php> emit an error if a value is returned: https://news-web.php.net/php.internals/129980
	* An earlier, similar, RFC: [[make_ctor_ret_void\|PHP RFC: Make constructors and destructors return void]]		* An earlier, similar, RFC: [[make_ctor_ret_void\|PHP RFC: Make constructors and destructors return void]]
		+	* Discussion of this RFC: https://news-web.php.net/php.internals/130808

	===== Rejected Features =====		===== Rejected Features =====

deprecate-metaphone

lamentxu (lamentxu@undisclosed.example.com) — 2026-05-08T08:27:56+00:00

2026/04/27 14:41		current
Line 3:		Line 3:
	* Date: 2026-04-25		* Date: 2026-04-25
	* Author: Weilin Du, lamentxu@163.com		* Author: Weilin Du, lamentxu@163.com
-	* Status: Under Discussion	+	* Status: Withdrawn
	* Implementation: https://github.com/php/php-src/pull/21889		* Implementation: https://github.com/php/php-src/pull/21889

override_constants - fix discussion thread link

daniels (daniels@undisclosed.example.com) — 2026-05-08T02:00:05+00:00

2026/05/08 02:00		current
Line 23:		Line 23:

	* Public and protected constants of a parent class or implemented interface satisfy <php>#[\Override]</php>. Private constants do not satisfy the attribute.		* Public and protected constants of a parent class or implemented interface satisfy <php>#[\Override]</php>. Private constants do not satisfy the attribute.
-	* <php>#[\Override]</php> is ignored on traits, but constants from a used trait behave as if the property definition was copied and pasted into the target class. Specifically the <php>#[\Override]</php> attribute on a trait constant requires the existence of a matching constant in a parent class or implemented interface.	+	* <php>#[\Override]</php> is ignored on traits, but constants from a used trait behave as if the constant definition was copied and pasted into the target class. Specifically the <php>#[\Override]</php> attribute on a trait constant requires the existence of a matching constant in a parent class or implemented interface.
	* <php>#[\Override]</php> works as expected on anonymous classes.		* <php>#[\Override]</php> works as expected on anonymous classes.
	* <php>#[\Override]</php> works as expected on interfaces: a matching constant needs to exist in a parent interface.		* <php>#[\Override]</php> works as expected on interfaces: a matching constant needs to exist in a parent interface.

foreach_void

jbafford (jbafford@undisclosed.example.com) — 2026-05-07T21:33:46+00:00

2025/04/03 13:08		current
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	====== PHP RFC: foreach iteration of keys without values ======		====== PHP RFC: foreach iteration of keys without values ======
-	* Version: 0.1	+	* Version: 0.2
-	* Date: 2016-01-09	+	* Date: 2026-05-08
		+	* Created Date: 2016-01-09
	* Author: John Bafford, john@bafford.com		* Author: John Bafford, john@bafford.com
-	* Status: Inactive	+	* Status: Draft
-	* First Published at: http://wiki.php.net/rfc/foreach_void	+	* First Published at: https://wiki.php.net/rfc/foreach_void
		+	* Implementation: https://github.com/jbafford/php-src/tree/foreachvoid

	===== Introduction =====		===== Introduction =====
-	When iterating with foreach, it is not possible to retrieve only the keys (and not also the values) without unnecessary extra work or semantic overhead. This RFC proposes new syntax that makes this possible.	+	When iterating with foreach, it is not possible to retrieve only the keys (and not also the values) without unnecessary extra work or semantic overhead. This RFC proposes the following new syntax that makes this possible.

-	===== Background =====	+	<PHP>
		+	foreach ($iterable as $key => void) {
		+	}
		+	</PHP>

-	At present, there are two main patterns in use to iterate over all of the keys of an array, both of which have drawbacks:	+	Although the primary motivation of this RFC is to introduce an explicit way to semantically iterate _only_ on keys, there are also performance benefits for doing this as well. The performance benefits are secondary to the semantic proposal.
		+
		+
		+	===== Background =====
		+	At present, there are two main patterns used to iterate over all of the keys of an array, both of which have drawbacks:

-	<code php>	+	<PHP>
	foreach ($source as $key => $value) {		foreach ($source as $key => $value) {
	// use the $key, ignore the $value		// use the $key, ignore the $value
	}		}
-	</code>	+	</PHP>

-	Retrieving the $value and ignoring it has a performance cost in that an opcode is emitted in compilation (and executed during iteration) to retrieve the value at each iteration. If the $value is never actually used, this is an unnecessary cost.	+	Retrieving the ``$value`` and ignoring it has a performance cost in that an opcode is emitted in compilation (and executed during iteration) to retrieve the value at each iteration. If the ``$value`` is never actually used, this is an unnecessary cost. Note that retrieving the value can be "expensive", such as if ``$source`` is an iterator.

-	Additionally, there is a semantic cost, in that even though the $value is intended to be unused, it still exists. There is no clear indication strictly via code that the value is intended to be unused. Even when the variable is named accordingly, such as $unused, $dummy, $ignore, $_, etc, it is not always clear as to the intent. For example, $unused, $dummy, and $ignore could be all be an accurate representation of the meaning of an array's values.	+	Additionally, there is a semantic cost, in that even though the ``$value`` is intended to be unused, it still exists. There is no clear indication strictly via code that the value is intended to be unused. Even when the variable is named accordingly, such as ``$unused``, ``$dummy``, ``$ignore``, ``$_``, etc, it is not always clear as to the intent. For example, ``$unused``, ``$dummy``, and `$ignore`` could be all be an accurate representation of the meaning of an array's values, causing unnecessary semantic confusion.


-	<code php>	+	<PHP>
	foreach (array_keys($array) as $key) {		foreach (array_keys($array) as $key) {
	}		}
-	</code>	+	</PHP>

-	Retrieving the list of array keys for iteration in this manner is more semantically pure because it clearly indicates intent, but it involves a performance cost as a result of the call to array_keys. (An additional traversal of the array, as well as the time and memory cost of allocating/deallocating a new array to receive copies of the keys from the source array.)	+	Retrieving the list of array keys for iteration in this manner is more semantically pure because it clearly indicates intent, but it involves a performance cost as a result of the call to array_keys: an additional traversal of the array, as well as the time and memory cost of allocating/deallocating a new array to receive copies of the keys from the source array.
		+
		+	Also, this method will not work when ``$array`` is not actually an array (such as if it is an iterator; in that case, one would need to call ``array_keys(iterator_to_array($array))``, and now there's even more of the same kind of overhead.


	===== Proposal =====		===== Proposal =====
		+	In order to iterate over an array (or generator, iterator, or other object that can be iterated) and retrieve only its keys, we add the following syntax:

-	In order to iterate over an array (or generator, or other object that can be iterated) and retrieve only its keys, we add the following syntax:	+	<PHP>
-		+
-	<code php>	+
	foreach ($source as $key => void) {		foreach ($source as $key => void) {
	}		}
-	</code>	+	</PHP>


	By adding this syntax, we gain the ability to iterate over the keys in a performant and semantically appropriate manner.		By adding this syntax, we gain the ability to iterate over the keys in a performant and semantically appropriate manner.

-	By not having a target variable that receives the value, an opcode is no longer emitted (or executed) to copy that value from the source. This provides a minor performance enhancement at runtime at the expense of a slightly more complicated parser and compiler for foreach.	+	In the implementation provided (see the implementation link in the header), this is accomplished with a slightly more complicated parser and compilation step.

		+	By not having a target variable that receives the value, an opcode is no longer emitted (or executed) to copy that value from the source. This provides a minor performance enhancement at runtime at the expense of a slightly more complicated parser and compiler for foreach. Because this is a change at the compilation level,

-	A new E_COMPILE_ERROR is also added. The error “foreach value target must be variable or void” is emitted if a key is requested and the value target specified is not a variable (or reference to a variable), or void.	+	A new ``E_COMPILE_ERROR`` is also added. The error “foreach value target must be variable or void” is emitted if a key is requested and the value target specified is not a variable (or reference to a variable), or void.

-	===== Patches and Tests =====
-	The GitHub Pull Request for this change is here: https://github.com/php/php-src/pull/XXX

-	While in draft, the direct link to the relevant tree is: https://github.com/jbafford/php-src/tree/foreachvoid	+	=== Syntax Decisions ===

		+	The following potential syntaxes have been previously suggested. They are not are being considered for this RFC, for the reasons stated below.
		+
		+
		+	==== Raw Underscore ====
		+
		+	<PHP>
		+	foreach ($array as $key => _) {
		+	}
		+	</PHP>
		+
		+	While ``_`` is used in some other languages to signify intent that a result will be ignored, PHP itself does not have that concept. Additionally, since ``_`` is a valid constant name, the above code would be semantically incongruous, because it would imply writing a value to a constant. Thus, it is not an appropriate syntax to consider for this feature.
		+
		+
		+	==== $ Underscore ====
		+	<PHP>
		+	foreach ($array as $key => $_) {
		+	}
		+	</PHP>
		+
		+
		+	It has also been suggested to use the variable ``$_`` to indicate that the value should be ignored, and also this could serve as a signal to static analyzers that the value should be ignored. PHP does not have a culture of using ``$_`` to indicate this. Even if that changed, and even if static analyzers understood this, there is no performance benefit to writing the code this way: PHP will still retrieve the value, even though it won't be used.
		+
		+
		+	==== Empty Target ====
		+
		+	<PHP>
		+	foreach ($array as $key => ) {
		+	}
		+	</PHP>
		+
		+	Leaving the value target empty visually looks like a mistake, rather than signaling a clear intent.
		+
		+
		+	==== Null ====
		+
		+	<PHP>
		+	foreach ($array as $key => null) {
		+	}
		+	</PHP>
		+
		+	In PHP, ``null`` is a value. Semantically, this would be similar to trying to assign to a constant, or a bool, int, float, or string literal. ``void`` is used to mean the complete absence of a value, as in the ``void`` return type.
		+
		+
		+	==== Examples ====
		+	•••• TODO ••••

	===== Backward Incompatible Changes =====		===== Backward Incompatible Changes =====
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	===== Proposed PHP Version(s) =====		===== Proposed PHP Version(s) =====
-	Next PHP 7.x.	+	Next PHP 8.x.

	===== RFC Impact =====		===== RFC Impact =====
-	There should be no adverse impact to SAPIs or existing extensions.	+	==== To the Ecosystem ====
		+	There are no backward-incompatible changes, so end-user code will not need changes, and will observe no impact.

-	The only change to opcodes emitted is that when the foreach value target is void, the opcode that sets the target variable is omitted. Accordingly, there should be no adverse impact to opcache.	+	The only change to opcodes emitted is that when the foreach value target is void, the opcode that sets the target variable is omitted. Accordingly, there should be no adverse impact to opcache. (••• this statement was correct in 2016, but it might be bogus now. verify. •••)
		+
		+	Code that reads and interprets PHP source code (such as IDEs, language servers (LSPs), static analyzers, auto-formatters, linters, and related userland PHP libraries) will need to:
		+	* add support for the `foreach($iterable as $key => void)` syntax;
		+	* infer that the `foreach($iterable as $key => void)` loop will be iterated with only the `$key`, and no value being set.
		+
		+	==== To Existing Extensions ====
		+	There should be no impact to extensions as a result of this syntax addition.
		+
		+	==== To SAPIs ====
		+	There should be no impact to SAPIs as a result of this syntax addition.

	===== Open Issues =====		===== Open Issues =====
	There are no open issues at this time.		There are no open issues at this time.

-	===== Proposed Voting Choices =====	+	===== Future Scope =====
-	* Whether to add ''foreach ($source as $key => void)'' syntax	+	Iterating over an `Iterator` or a generator will still cause the creation of each value, even though they are not emitted into the `foreach` loop. This might be expensive. It might be possible to extend the relevant APIs to allow explicitly iterating over keys, so that expensive values do not need to be produced when they are not used.
		+
		+	`foreach($iterable as void)`, where the loop body is called once per each element in the iterable, without receiving any keys or values, is technically feasible, but is not proposed by this RFC.
		+
		+	===== Voting Choices =====
		+	Pick a title that reflects the concrete choice people will vote on.
		+
		+	Please consult [[https://github.com/php/policies/blob/main/feature-proposals.rst#voting-phase\|the php/policies repository]] for the current voting guidelines.
		+
		+	----
		+
		+	Primary Vote requiring a 2/3 majority to accept the RFC:
		+
		+	<doodle title="Implement foreach-void as outlined in the RFC?" voteType="single" closed="true" closeon="2026-04-08T00:00:00Z">
		+	* Yes
		+	* No
		+	* Abstain
		+	</doodle>
		+
		+	===== Patches and Tests =====
		+	The GitHub Pull Request for this change is here: https://github.com/php/php-src/pull/XXX
		+
		+	While in draft, the direct link to the relevant tree is: https://github.com/jbafford/php-src/tree/foreachvoid
		+
		+	===== Implementation =====
		+	After the RFC is implemented, this section should contain:
		+	- the version(s) it was merged into
		+	- a link to the git commit(s)
		+	- a link to the PHP manual entry for the feature
		+
		+	===== References =====
		+	* [2020 thread on Internals](https://externals.io/message/111774)
		+
		+	===== Rejected Features =====
		+	Keep this updated with features that were discussed on the mail lists.
		+
		+	===== Changelog =====
		+	* v0.1: Created in 2016
		+	* v0.2: Revised in 2026. No changes to the core of the proposal, just clarifications of the rationale and inclusion of benchmarks.
		+
		+	••• todo: benchmarks •••

-	This proposal adds new syntax. Accordingly, it requires a 2/3 vote.

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