Language: class const `new` accepted under PROFILE=8.4 — Zend rejects (Zend/zend_compile.c)

[PurHur]

Category

Language · php-src-strict · illegal new in class constant (Pillar 4)

Problem

Under PHP_COMPILER_PROFILE=8.4, public const X = new stdClass; compiles and evaluates. Zend 8.4.23 (and 8.2) reject at compile time: Fatal error: New expressions are not supported in this context. Parameter defaults / static-variable new remain legal on both sides — only class constants (and property defaults) must stay forbidden.

Probed 2026-07-20 vs php:8.4-cli (8.4.23) and PHP_COMPILER_PROFILE=8.4 php bin/vm.php.

Repro	Zend 8.4.23	VM PROFILE=8.4
class A { public const X = new stdClass; }	Fatal: New expressions are not supported in this context	compiles → object ❌
function f($x = new stdClass){}	OK	OK
function g(){ static $x = new stdClass; }	OK	OK

Snapshot #9978 mentioned class-const new; this is the concrete child issue.

php-src reference

• php/php-src Zend/zend_compile.c — const-expr new reject (zend_compile_const_expr)
• PHP 8.1 “new in initializers” RFC — allows param/static-var/attribute defaults, not class constants or property defaults

PHP implementation target

• lib/Compiler/NewWithoutParensCompileCheck.php (and related const-expr compile path) — keep reject on class const / property default for all profiles including forward 8.4
• No new C

Repro

./script/docker-exec.sh -- bash -lc 'export PHP_COMPILER_PROFILE=8.4
printf "%s\n" "<?php class A { public const X = new stdClass; } echo gettype(A::X);" > /tmp/c.php
php bin/vm.php /tmp/c.php; echo exit:$?
# expect compile fatal matching Zend
'

Done when

• Class const / property-default new fatals like Zend under default + PROFILE=8.4 (VM/JIT/AOT parse)
• Param-default + static-var new still work
• Compliance guard + repro exits non-zero / matches Zend message
• php-src-strict

Related

• Pillar 4 (Strategic alignment: compiler excellence pillars (2026 H2) #10533) · snapshot #9978

[PurHur]

claim: worker-lane-B — starting this run

Pillar 1 probe (local): docker OK; bootstrap-inventory.php --check shows doc drift on ext/dom/VmDom.php (method count) — regenerating only if this change touches inventory. Proceeding with language reject for class-const new under PROFILE=8.4.

[PurHur]

Merged via #21496

Verification (php-src-strict):

• PHP_COMPILER_PROFILE=8.4 php test/repro/issue_21493_class_const_new_reject.php → reject class-const / property defaults; allow param-default + static-var
• Ticket repro php bin/vm.php on const X = new stdClass → exit 255, message matches Zend
• VM/JIT compliance filters for reject PHPTs green; capability-syntax class_const_object → no/no/no