Language: public private(set) property — parse accepted, Zend rejects multiple access modifiers (Zend/zend_compile.c)

[PurHur]

Category

language · php-src-strict · PHP 8.4 asymmetric visibility

Problem

Combining explicit public with private(set) on the same property is a parse/compile error in Zend ("Multiple access type modifiers are not allowed"). This compiler accepts the declaration and runs user code.

Repro	Zend 8.2+	VM (2026-07-04)
public private(set) string \$x;	parse error (multiple access modifiers)	compiles; echoes hi then Error on external write

php-src reference

• php/php-src Zend/zend_compile.c — property modifier validation (zend_compile_property_decl)
• php/php-src Zend/zend_language_parser.y — asymmetric visibility grammar

PHP implementation target

• lib/Compiler.php / parser — reject public + private(set) / protected(set) combinations at parse or compile time
• lib/ property visibility lowering — do not treat as valid asymmetric visibility until grammar matches php-src

Repro

./script/docker-exec.sh -- php bin/vm.php test/repro/maintainer_gap_asymmetric_visibility_public_private_set.php

Done when

• Repro fails at parse/compile with Zend-equivalent diagnostic (not runtime Error on valid-looking code)
• Compliance .phpt guard under test/compliance/cases/language/
• php-src-strict; no php-compiler-strict shortcut

[PurHur]

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

[PurHur]

claim released: public private(set) is valid PHP 8.4 asymmetric visibility (php.net); reference profile already rejects via AsymmetricVisibilityRejector + asymmetric_double_modifier_reference_profile.phpt. Pivoting to #16133 (AOT build regression).

[PurHur]

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

[PurHur]

claim released: reference profile already rejects via AsymmetricVisibilityRejector (Fatal: Multiple access type modifiers). On PHP_COMPILER_PROFILE=8.4, public private(set) is valid PHP 8.4 per php.net — matches intended forward-profile behavior. Pivoting to another lane C issue.

[PurHur]

claim: cursor-agent-lane-a — starting this run (lane A queue stale; language parity #16142)

[PurHur]

Merged via #16613.

Verification:

• php test/repro/maintainer_gap_asymmetric_public_private_set_compile.php — Zend fatal (exit 255)
• php bin/vm.php test/repro/maintainer_gap_asymmetric_public_private_set_compile.php — compile fatal: Multiple access type modifiers are not allowed (exit 255)
• php vendor/bin/phpunit --filter asymmetric_visibility_public_private_set_compile — OK
• Parenthesized public (private(set)) path unchanged (existing compliance tests green).