Regression: enum trait instance methods on cases — Method call on non-object (re-#6623, zend_enum.c)

[PurHur]

Category

language — regression

Problem

Enums may use traits with instance methods; calling those methods on enum cases must work like Zend. Closed #5709 / #6623 fixed trait merge on enums, but VM now fails case method dispatch.

php-src reference

• php/php-src Zend/zend_enum.c — enum object model
• php/php-src Zend/zend_traits.c — trait method merge

Repro

test/repro/maintainer_enum_use_trait.php:

<?php
trait T {
    public function m(): void {
        echo "trait\n";
    }
}
enum E: int {
    use T;
    case A = 1;
}
E::A->m();

php test/repro/maintainer_enum_use_trait.php
# Zend: trait

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_enum_use_trait.php'
# VM today: Method call on non-object

	Zend	VM today
E::A->m()	prints trait	Method call on non-object

Scope

• VM enum case object dispatch — trait-merged methods on backed enum cases
• JIT/AOT must match when enum method calls are lowered
• PHP implementation in lib/ / ext/ — no new C runtime branches

Done when

• Repro prints trait under php bin/vm.php
• JIT/AOT agree if enum instance calls are in scope
• Targeted compliance PHPT or repro guard green in ./script/ci-fast.sh
• php-src-strict

Links

• Language: enum using traits — trait instance methods on enum cases (zend_enum.c, zend_traits.c) #5709, Language: enum use Trait — trait methods not merged (php-cfg + VM, zend_enum.c) #6623 (closed fixes)
• Regression: backed enum case fetch materializes backing scalar not enum object (re-#8725, zend_enum.c) #8746 (enum case materialization — related object-model regression)

[PurHur]

claim: worker-lane-c — starting this run

[PurHur]

Merged via #8823.

Finding: The regression described in this issue was already fixed on master before this run — enum case fetches now materialize as enum case objects (#8767 / #8725), so E::A->m() dispatches trait methods correctly.

This PR adds:

• test/repro/maintainer_enum_use_trait.php (issue repro)
• Regression: enum trait instance methods on cases — Method call on non-object (re-#6623, zend_enum.c) #8808 tag on existing enum_trait_use.phpt compliance guard

Verification:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/repro/maintainer_enum_use_trait.php
php vendor/bin/phpunit test/compliance/EnumTraitMethodTest.php --filter enum_trait_use
php vendor/bin/phpunit test/compliance/EnumTraitMethodJitTest.php --filter enum_trait_use
'
# trait
# OK (1 test, 1 assertion) ×2

[PurHur]

Maintainer triage (2026-06-16): Reopened — repro still red on master.

```bash
php bin/vm.php test/repro/maintainer_enum_use_trait.php

Method call on non-object (exit 255)

php test/repro/maintainer_enum_use_trait.php

trait (Zend 8.2)

```

Pairs #8746 enum case materialization. Compliance test/compliance/cases/language/enum_trait_use.phpt should guard fix.

[PurHur]

claim: worker-lane-c — starting this run