Language: promoted constructor public (private(set)) parameter — parse rejected on 8.4 profile (Zend/zend_compile.c)

[PurHur]

Category

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

Problem

PHP 8.4 allows asymmetric visibility on promoted constructor parameters, e.g. public function __construct(public (private(set)) int $x = 1) {}. Zend 8.4 accepts and runs the program; with PHP_COMPILER_PROFILE=8.4 this compiler fails at parse/compile with unexpected token "private".

Repro	Zend 8.4+	VM profile 8.4 (2026-07-05)
class D { public function __construct(public (private(set)) int $x = 1) {} }	compiles; $d->x readable	syntax error, unexpected token "private"

(Related but distinct from #16142 — duplicate access modifiers on a plain property.)

php-src reference

• php/php-src Zend/zend_compile.c — promoted-parameter asymmetric visibility parsing/lowering
• php/php-src Zend/zend_language_parser.y — grammar for (private(set)) on promoted params

PHP implementation target

• lib/ parser/preprocessor — extend promoted-parameter grammar for parenthesized asymmetric visibility (8.4 profile gate)
• lib/Compiler.php / property hook + visibility lowering — emit correct read/write scopes for promoted asymmetric fields
• Prefer PHP lowering; no new C runtime branches

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && PHP_COMPILER_PROFILE=8.4 php bin/vm.php test/repro/maintainer_gap_promoted_private_set.php'

Done when

• PHP_COMPILER_PROFILE=8.4: promoted public (private(set)) parses and matches Zend read/write access rules
• Compliance .phpt guard under test/compliance/cases/language/
• php-src-strict on 8.4 profile; no php-compiler-strict shortcut

[PurHur]

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

[PurHur]

claim: cursor-agent-lane-b — continuing implementation (rejectPromotedParamParenthesizedAsymmetricSet gate)

[PurHur]

Merged via #16515.

Fix: Gate rejectPromotedParamParenthesizedAsymmetricSet behind CompilerVersion::supportsParenthesizedAsymmetricSetModifier() so public (private(set)) on promoted constructor params parses on the 8.4 profile; existing rewriter markers handle read/write scopes.

Verification:

• ./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && PHP_COMPILER_PROFILE=8.4 php bin/vm.php test/repro/maintainer_gap_promoted_private_set.php' → 1
• VM compliance (5 tests: promoted_private_set, promoted_paren_private, promoted_asymmetric_visibility_public_private, asymmetric_visibility_promoted_ctor, promoted_asymmetric_visibility_fatal) → OK
• PropertyHooksTest::testPromotedAsymmetricVisibilityParenthesizedFormCompilesOn84Profile → OK
• ./script/ci-fast.sh → exit 0