Language: first-class callable (strlen(...), Foo::bar(...)) must yield Closure objects (zend_compile.c)

Problem

PHP 8.1+ first-class callables must be Closure instances (or invokable objects with __invoke), not compile-time string/[class, method] placeholders. This build lowers strlen(...), array_slice(...), and Foo::bar(...) to strings or array pairs, so is_object($f) is false and var_export() shows 'strlen' instead of a Closure::__set_state array.

Related closed tracker #1230 (parse/lowering landed) but runtime zval type still diverges from Zend.

php-src reference

php/php-src Zend/zend_compile.c — zend_compile_first_class_callable()
php/php-src Zend/zend_closures.c — zend_create_closure()

Repro

test/tmp/repro-fcc-closure-object.php:

<?php
declare(strict_types=1);
$f = strlen(...);
var_export(is_object($f));
echo PHP_EOL;
var_export($f instanceof Closure);
echo PHP_EOL;

./script/docker-exec.sh -- bash -lc 'php test/tmp/repro-fcc-closure-object.php; php bin/vm.php test/tmp/repro-fcc-closure-object.php'

Check	Zend	This compiler
`is_object($f)`	`true`	`false`
`$f instanceof Closure`	`true`	`false`

Also: array_slice(...) — Zend true, VM false (same lowering).

Scope

Module	Path
Compiler	`lib/Compiler.php` — `compileFirstClassCallable()`
VM	Closure / callable object construction
Tests	`test/compliance/cases/language/` + JIT when execute probe green

Done when

strlen(...), static Foo::bar(...), and instance [$o, 'm'](...) FCC forms are Closure (or Zend-equivalent invokable)
is_callable($fcc) / call_user_func($fcc, ...) parity with Zend on the repro
./script/ci-fast.sh --filter first_class (or new compliance case name) green

true / true (Zend) → true / true (VM)

vendor/bin/phpunit --filter first_class_callable_closure_object # OK (2 tests)
```

Function/static FCC are Closure objects on VM+JIT; instance-method FCC still blocked at compile by TypeReconstructor::array() (tracked separately).

Fix first-class callables to produce Closure objects (#4810) (#4961)

Cleanup: deleting leftover test/tmp/ scratch repro for this closed issue — same coverage lives under test/compliance/cases/ (see PR chore/cleanup-stale-test-tmp-repros).

Cleanup follow-up: merged #25413 — test/tmp scratch repro removed.

Chore: drop stale test/tmp repros superseded by compliance (#4812/#4810/

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Language: first-class callable (`strlen(...)`, `Foo::bar(...)`) must yield Closure objects (zend_compile.c) #4810

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php-src reference

Repro

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Done when

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true / true (Zend) → true / true (VM)

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Language: first-class callable (strlen(...), Foo::bar(...)) must yield Closure objects (zend_compile.c) #4810

Description

Category

Problem

php-src reference

Repro

Scope

Done when

Related

Activity

PurHur commented on Jun 3, 2026

PurHur commented on Jun 3, 2026

true / true (Zend) → true / true (VM)

PurHur commented on Jul 30, 2026

PurHur commented on Jul 30, 2026

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Language: first-class callable (`strlen(...)`, `Foo::bar(...)`) must yield Closure objects (zend_compile.c) #4810