Stdlib: settype() on enum cases — must emit Warning before int coercion (ext/standard/type.c, php-src-strict)

[PurHur]

Category

stdlib | php-src-strict

Problem

settype($var, 'int') (and other scalar targets) on a backed enum case variable silently coerces to the backing value in this compiler. Zend emits Warning: Object of class E could not be converted to int before applying the conversion — observable via error handlers and error_reporting.

The VM path uses EnumCaseSupport::tryCastToInt() in ext/standard/VmSettype.php without surfacing the php-src warning.

php-src reference

• php/php-src ext/standard/type.c — php_settype, zend_convert_to_long object branch
• php/php-src Zend/zend_operators.c — object-to-scalar conversion warnings

Repro (verified 2026-06-16)

test/repro-maintainer/parity_settype_enum_warning.php:

<?php
declare(strict_types=1);

enum E: int { case A = 1; }

$e = E::A;
settype($e, 'int');
var_export($e);
echo "\n";

./script/docker-exec.sh -- bash -lc 'php test/repro-maintainer/parity_settype_enum_warning.php 2>&1'
./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro-maintainer/parity_settype_enum_warning.php 2>&1'

Runtime	Output
Zend PHP 8.2	Warning: Object of class E could not be converted to int then 1
VM (today)	1 (no warning) ❌

Scope (PHP-in-PHP)

Layer	Path
VM	ext/standard/VmSettype.php, ext/standard/VmScalarType.php — emit E_WARNING via VM error API before enum backing coercion
JIT	ext/standard/JitSettype.php — match warning + result
Tests	test/compliance/cases/stdlib/settype_enum_warning.phpt

Implement in ext/standard/ — no new runtime/*.c coercion tables.

Done when

• VM emits Warning matching Zend substring before coercing enum case to int/float/string targets
• settype($e, 'object') on enum still preserves enum object (existing behavior)
• ./script/ci-fast.sh --filter settype_enum_warning green
• php-src-strict: VM/JIT agree

Related

• Stdlib: bindec()/hexdec()/octdec() — enum case operands must TypeError (ext/standard/string.c, php-src-strict) #8863 bindec/hexdec/octdec enum TypeError (input rejection, not settype)
• Regression: gettype() on backed enum cases returns integer not object (re-#5496, basic_functions.c) #8810 gettype() enum return type
• Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492 self-host

[PurHur]

claim: worker-lane-b — batch (issues #8977, #8974, #8998, #9025)

[PurHur]

claim released: worker-lane-b — already green on master (E_WARNING + settype_backed_enum.phpt).

[PurHur]

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

[PurHur]

claim released: warning already emitted — settype_backed_enum.phpt green on master (Object of class E could not be converted to int). Pivoting.

[PurHur]

claim: cursor-agent-lane-b — starting this run (fix @settype + var_export(gettype()) misbind; settype_backed_enum_int.phpt red on master)

[PurHur]

Merged via #16309.

Fix: @settype() suppress return slot no longer aliases the first dead-temp arg of a later sibling call when an adjacent nested callee (e.g. gettype()) feeds that arg — var_export(gettype($x)) after @settype($x,'int') now prints 'integer' not true.

Verify:

• vendor/bin/phpunit --filter settype_backed_enum — 4/4 OK
• vendor/bin/phpunit --filter ErrorSuppressInlineReturnSlotTest — 8/8 OK
• php bin/vm.php test/repro/maintainer_gap_settype_var_export_gettype.php → 1\n'integer'
• make bootstrap-selfhost-link — OK