Language: typed class constants — const array/string/int (PHP 8.3, Zend zend_constants.c parity) #3592

Category

language

Problem

PHP 8.3+ allows typed class constants (public const array X = [1, 2];, const string NAME = 'x';). Zend validates types at compile time and stores values in the class constant table. This compiler accepts the syntax but defineClass() rejects non-scalar constant values even when the RHS is a literal array:

LogicException: Class constant value must be a compile-time constant

(VM stack: lib/VM.php:2415, May 2026).

Distinct from #3196 (object constants const X = new Foo();).

php-src reference

• php/php-src Zend/zend_compile.c — typed const validation (zend_compile_class_const)
• php/php-src Zend/zend_constants.c — constant table + type info
• php/php-src Zend/zend_type.c — zend_verify_const_type

Repro (today)

<?php
class C {
    public const array X = [1, 2];
}
echo C::X[0];

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php /path/to/repro.php'

Expected (Zend): 1.
Actual: fatal Class constant value must be a compile-time constant during class registration.

Scope (this repo)

• lib/Compiler.php — materialize literal array/string/int/float/bool/null const values at compile time
• lib/VM.php — store typed constants; enforce type on fetch; C::X[$i] dim fetch on array constants
• Type mismatch assignment at declare time → compile-time TypeError (Zend parity)
• test/compliance/cases/language/typed_class_const.phpt
• script/capability-syntax.php — document PHP 8.3 typed constants row

Done when

• public const array X = [1,2]; and const string S = 'a'; work on VM; wrong-type value fails at compile time
• echo C::X[0]; prints 1 in repro
• JIT/AOT: either lower immutable constant arrays or document VM-only deferral in matrix