Language: backed enum case === / == with backing scalar must be false (zend_operators.c)

[PurHur]

Category

language

Problem

Identity and equality between a enum case object and its backing scalar must be false in PHP 8.1+:

• E::A === 1 → false
• E::A == 1 → false

This compiler returns true for both (backing coercion in compare).

php-src reference

• php/php-src Zend/zend_operators.c — compare_function, enum case handling

Repro

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

Engine	===	==
Zend	false	false
VM	true	true

Scope

• lib/VM/Variable.php (or compare helpers) — do not equate TYPE_ENUM_CASE to backing int
• JIT/AOT compare lowering (phase 2)

Done when

• VM returns false for === and == in repro
• PHPT test/compliance/cases/language/enum_compare_backing_scalar.phpt green

Related

• Stdlib: in_array() loose comparison must not match enum case to backing scalar (ext/standard/array.c) #5592, Stdlib: array_search() strict — enum needle must not match coerced backing int in haystack (ext/standard/array.c) #5668 (in_array / array_search loose+strict), Language: (int)/(float) cast on backed enum regression vs closed #5714 (zend_operators.c) #5791 (casts)

[PurHur]

claim: cursor-agent-lane-c — starting this run

[PurHur]

Merged via #5802

Verification: maintainer repro + EnumVMTest filter enum_compare_backing_scalar — VM returns false for E::A === 1, E::A == 1, and string-backed S::B === 'x' / == 'x' (both operand orders).

Change: explicit enum-case vs non-case rejection in Variable::identicalTo / equals so compare never falls through to looseEqual numeric coercion.