Language: static closure bindTo()/bind() with $this must Error (Zend/zend_closures.c parity)

Problem

PHP static function () { ... } closures must not receive a bound $this. Zend rejects Closure::bindTo($obj) and Closure::bind($closure, $obj, ...) on static closures with:

Cannot bind static closure to object

This compiler creates static closures without boundThis (lib/VM.php FLAG_STATIC check) but ClosureSupport::bindTo() (lib/VM/ClosureSupport.php) does not verify the closure is non-static — binding $this succeeds silently, breaking visibility/$this semantics vs Zend.

php-src reference

php/php-src Zend/zend_closures.c — zend_closure_bind(), static-closure guard
php/php-src Zend/zend_closures.h — ZEND_ACC_STATIC on closure function

Repro (behavior gap today)

<?php
declare(strict_types=1);

class C {
    public int $x = 1;
    public function make(): Closure {
        return static function () {
            return 0;
        };
    }
}

$c = new C();
$fn = $c->make();
try {
    $bound = $fn->bindTo($c);
    var_export($bound !== null);
    echo "\n";
} catch (Throwable $e) {
    echo get_class($e), ': ', $e->getMessage(), "\n";
}

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php repro.php
php repro.php
'

Runtime	Result
Zend PHP	`Error: Cannot bind static closure to object`
`bin/vm.php`	`true` (bind appears to succeed) ❌

Also test Closure::bind($fn, $obj, 'C') — same Error on Zend.

Scope (this repo)

Layer	Path
VM	`lib/VM/ClosureSupport.php` — detect static closure (`ClosureState` / wrapped func `FLAG_STATIC`) before assigning `boundThis`
JIT/AOT	`lib/JIT/ClosureBindHelper.php` — emit same Error path
Tests	`test/compliance/cases/language/static_closure_bind.phpt`

Track static fn () => (arrow) separately if desugar omits static flag — should share the same guard.

Done when

Repro throws catchable Error with Zend message on VM
bindTo(null) / unbind still allowed on static closures (Zend permits)
JIT/AOT repro matches VM (./phpc jit repro.php)
./script/ci-fast.sh --filter static_closure_bind green

Language: Closure::fromCallable() and Closure::bindTo() (Zend zend_closures.c parity) #3266 / Language: Closure::bind() static method — rebind callable scope (Zend zend_closures.c) #3673 Closure bind · Language: Closures and anonymous functions #72 closures · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

claim: worker-lane-c — starting this run

Merged via #4619.

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && vendor/bin/phpunit test/compliance/ClosureVMTest.php --filter static_closure_bind' — OK (1 test)
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/jit.php' on issue repro — Error: Cannot bind static closure to object

VM and JIT now match Zend for static function + bindTo/bind with an object $this; bindTo(null) still allowed.

Fix static closure bindTo/bind Error parity (#4613). (#4619)

claim: cursor-agent-lane-c — reopening: static_closure_bind.phpt fatals in returnTypeCallableName (func->class Literal); fixing and re-verifying #4613 done-when.

Fix returnTypeCallableName Literal crash blocking static closure bind (…

Merged via #10425.

Root cause: returnTypeCallableName() concatenated func->class (a PHPCfg\Operand\Literal) when enforcing : Closure return types, fatally aborting before ClosureSupport::bindTo() could throw.

Fix: Read func->class->value for the callable label. VM/JIT now emit Error: Cannot bind static closure to object per Zend; bindTo(null) still returns an object.

Verification:
```bash
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/compliance/cases/language/static_closure_bind.phpt
php bin/jit.php test/compliance/cases/language/static_closure_bind.phpt
./vendor/bin/phpunit --filter static_closure_bind
'
```

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Language: static closure bindTo()/bind() with $this must Error (Zend/zend_closures.c parity) #4613

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Language: static closure bindTo()/bind() with $this must Error (Zend/zend_closures.c parity) #4613

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Problem

php-src reference

Repro (behavior gap today)

Scope (this repo)

Done when

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PurHur commented on Jun 2, 2026

PurHur commented on Jun 2, 2026

PurHur commented on Jun 21, 2026

PurHur commented on Jun 21, 2026

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