Runtime: object array offset — isset()/array_key_exists() must TypeError (Illegal offset type) #6500

Category

language | runtime

Problem

Using a plain object as an array lookup key must throw TypeError: Illegal offset type. This compiler emits an internal Unknown index type 5 (or similar) from hash-table helpers instead of a catchable Zend-compatible TypeError.

Distinct from #5853 (enum case write offsets) and #5755 (enum case lookup in builtins) — this is the general illegal offset type guard for arbitrary objects on read/exists paths.

php-src reference

• php/php-src Zend/zend_hash.c — _zend_hash_index_find, illegal offset checks
• php/php-src ext/standard/array.c — array_key_exists() → zend_hash_index_exists

Repro

<?php
class K {}
$a = [];
$a[new K] = 1; // may also need guard on write (separate from enum #5853)

try {
    var_export(array_key_exists(new K, $a));
} catch (Throwable $e) {
    echo get_class($e), ': ', $e->getMessage(), "\n";
}

try {
    var_export(isset($a[new K]));
} catch (Throwable $e) {
    echo get_class($e), ': ', $e->getMessage(), "\n";
}

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php -r "
class K {} \$a=[]; \$a[new K]=1;
try { array_key_exists(new K, \$a); } catch (Throwable \$e) { echo get_class(\$e), \": \", \$e->getMessage(); }
" 2>&1
'

php-src-strict

• Enum case operands follow Stdlib: array_key_exists()/isset() with enum case lookup key must TypeError (zend_hash.c, ext/standard/array.c) #5755 / Language: enum case as array offset must TypeError (Illegal offset type) (zend_hash.c) #5853 — this issue covers non-enum objects and aligns error class/message with Zend.

Scope

Done when

• array_key_exists($obj, $arr), isset($arr[$obj]), and key_exists($obj, $arr) throw TypeError: Illegal offset type
• Repro passes under php bin/vm.php inside script/docker-exec.sh
• ./script/ci-fast.sh --filter illegal_offset_object green
• No regression on int/string key paths

Related

• Language: enum case as array offset must TypeError (Illegal offset type) (zend_hash.c) #5853 · Stdlib: array_key_exists()/isset() with enum case lookup key must TypeError (zend_hash.c, ext/standard/array.c) #5755 · Stdlib: array_combine() with enum case keys — Error not backed int keys (ext/standard/array.c) #5538 · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492