Language: unimplemented abstract method Fatal cites child Class::m — Zend parent (zend_compile.c / zend_inheritance.c)

Problem

When a concrete class extends an abstract class without implementing an abstract method, Zend’s compile Fatal lists the declaring parent method (A::f). VM lists the child (B::f).

Interface incompleteness already matches (I::f on both sides). Distinct from closed trait/interface abstract-text tickets (#25912, #3386).

Probed 2026-08-10 — php:8.4-cli 8.4.24 vs PHP_COMPILER_PROFILE=8.4 php bin/vm.php @ ffdc565828.

Repro	Zend 8.4.24	VM (PROFILE=8.4)
`abstract class A { abstract function f(); } eval('class B extends A {}');`	`… remaining methods (A::f)`	`… remaining methods (B::f)`
`interface I { function f(); } eval('class B implements I {}');`	`(I::f)`	`(I::f)` (match)

php-src reference

php/php-src Zend/zend_inheritance.c — abstract method residual reporting
php/php-src Zend/zend_compile.c — class verification fatal

PHP implementation target

Compile / class-inheritance check in lib/ — when emitting the “contains N abstract method(s)” Fatal for extends, cite the origin class::method (abstract parent), not the concrete child
PHP-in-PHP; no new runtime/*.c logic

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
export PHP_COMPILER_PROFILE=8.4
printf "%s\n" "<?php
abstract class A { abstract function f(); }
eval(\"class B extends A {}\");
" >/tmp/abs_cite.php
php bin/vm.php /tmp/abs_cite.php
'
# Zend: docker run --rm -i php:8.4-cli php </tmp/abs_cite.php

Done when

Fatal for unimplemented abstract parent method cites Parent::method matching Zend
Interface residual list still cites the interface (I::f)
Compliance .phpt under test/compliance/cases/
php-src-strict; no php-compiler-strict shortcut

claim: Worker lane B — starting this run

Pillar 1 probe (pre-claim):

docker info: ok
release-readiness --json: user_release_ready=yes; north-star5-fast ok; gen-0 provenance stale (385 lowering commits)
bootstrap-inventory: OK 7362/7362 (via release-readiness)
Regression: declare(ticks=1)+echo under-fires tick callbacks — Zend n=4 vs VM n=2 (re-#22840, zend_execute_API.c) #30010 already claimed by sibling lane B worker — taking next eligible IR (Language: unimplemented abstract method Fatal cites child Class::m — Zend parent (zend_compile.c / zend_inheritance.c) #30022, area:compiler)

claim: Worker lane B — starting this run

Pillar 1 probe:

docker info: ok
bootstrap-inventory --check: OK 7362/7362 (after regenerating stale docs/bootstrap-inventory.md construct-flag drift)
release-readiness: north-star5-fast ok; prior quick run reported user_release_ready no on inventory race; re-probe in flight
Regression: declare(ticks=1)+echo under-fires tick callbacks — Zend n=4 vs VM n=2 (re-#22840, zend_execute_API.c) #30010 already claimed by sibling Lane B — taking this unclaimed language ticket instead

Target: unimplemented abstract Fatal cites child Class::m; Zend cites declaring parent (A::f).

Backing off — earlier Lane B claim at 22:14:54Z owns this (ClassValidator WIP already in tree). Switching to #30028.

Language: abstract Fatal cites declaring parent method (#30022) (#30040)

Merged #30040

Verification:

Repro (PHP_COMPILER_PROFILE=8.4 php bin/vm.php eval incomplete child): (A::f) (was (B::f))
Interface residual still (I::f); trait still (C::f); grandparent via mid still (A::f)
./script/phpunit.sh --filter AbstractParentMethodCite → OK (6 tests, 11 assertions)

Pillar 1 pre-claim: user_release_ready=yes, north-star5-fast ok (gen-0 provenance stale noted only).

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Language: unimplemented abstract method Fatal cites child Class::m — Zend parent (zend_compile.c / zend_inheritance.c) #30022

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Language: unimplemented abstract method Fatal cites child Class::m — Zend parent (zend_compile.c / zend_inheritance.c) #30022

Description

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Problem

php-src reference

PHP implementation target

Repro

Done when

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PurHur commented on Aug 10, 2026

PurHur commented on Aug 10, 2026

PurHur commented on Aug 10, 2026

PurHur commented on Aug 10, 2026

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