Regression: enum case ::class — operand still backing int after #9827 (Zend/zend_compile.c)

[PurHur]

Category

language · php-src-strict · regression (re-#9811, merged #9827)

Problem

E::Case::class must return the enum FQCN string on enum case operands. #9827 added tests and resolveClassPseudoConstFromOperand() for TYPE_ENUM_CASE, but direct TYPE_CLASS_CONST_FETCH on E::A::class still sees the class operand as a backing scalar int — resolveClassPseudoConstFromOperand() returns null and VM emits:

TypeError: Cannot use "::class" on value of type int

Root cause: enum case fetch at use-site materializes backing value before ::class pseudo-constant resolution (same enum-preservation cluster as #9727, #9712).

php-src reference

• php/php-src Zend/zend_compile.c — ZEND_FETCH_CLASS_CONSTANT, ::class on enum cases without scalarizing
• php/php-src Zend/zend_enum.c — enum case object identity

Repro (failure on master 2026-06-19)

<?php
enum E: int { case A = 1; case B = 2; }
echo E::A::class, "\n";
echo (E::B)::class, "\n";
$a = E::A;
echo $a::class, "\n";
enum U { case C; }
echo U::C::class, "\n";

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

Engine	Output
Zend PHP 8.3+	four lines: E, E, E, U
VM today	Fatal TypeError on first E::A::class

Existing guard file: test/repro/maintainer_enum_case_class_pseudo.php.

Scope (this repo)

Layer	Path
Compiler	lib/Compiler.php — preserve enum case object (or dedicated opcode) through ::class fetch
VM	lib/VM.php — TYPE_CLASS_CONST_FETCH + resolveClassPseudoConstFromOperand()
JIT	lib/JIT.php — same identity rules when lowering fetch
Tests	extend test/compliance/cases/language/enum_case_class_pseudo.phpt

PHP-in-PHP only — no new C runtime branches.

Done when (php-src-strict)

• Repro prints four FQCN lines on VM matching Zend
• Parenthesized, variable, and unit-enum cases from maintainer repro stay green
• ./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && vendor/bin/phpunit --filter enum_case_class_pseudo' green
• ./script/ci-fast.sh --filter enum_case_class_pseudo green

Related

• Closed Language: enum case ::class pseudo-constant — TypeError when case materialized as backing scalar (Zend/zend_compile.c) #9811 / Close #9811: enum case ::class pseudo-const guard tests #9827 (incomplete) · enum cluster Regression: enum case loose == / != with backing scalar returns true (re-#9660/#9583, Zend/zend_operators.c) #9727 · North star #1492

[PurHur]

claim: worker-lane-c — starting this run

[PurHur]

claim released: verified on current master — issue repro and acceptance criteria all green; no code change required this run.

Verification (2026-06-19, docker-exec):

```bash
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/repro/maintainer_enum_case_class_pseudo.php
php bin/jit.php test/repro/maintainer_enum_case_class_pseudo.php
vendor/bin/phpunit --filter enum_case_class_pseudo'
```

Output:
```
E
E
E
U
E
E
E
U
OK (2 tests, 2 assertions)
```

Root cause from #9827 (`tryFoldEnumCaseClassPseudoConstFqcn` + `resolveClassPseudoConstFromOperand` for `TYPE_ENUM_CASE`) is present on master. Recommend closing #9830 as stale filing.

[PurHur]

claim: worker-lane-c — starting this run

[PurHur]

Verified fixed on master (2026-06-20, worker-lane-c).

Verification:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/repro/maintainer_enum_case_class_pseudo.php
vendor/bin/phpunit --filter enum_case_class_pseudo'

Output:

E
E
E
U
OK (2 tests, 2 assertions)

Root cause from #9827 (tryFoldEnumCaseClassPseudoConstFqcn + resolveClassPseudoConstFromOperand for TYPE_ENUM_CASE) is present on master. Closing as stale filing — no code change required.