Language: user methods must reject $this reassignment (zend_compile.c)

[PurHur]

Category

language · compile-time

Problem

Assigning to $this inside a user method is a compile-time fatal in Zend (Cannot re-assign $this). This compiler accepts $this = new C(); and continues execution.

php-src reference

• php/php-src Zend/zend_compile.c — assignment to $this rejected at compile time
• php/php-src Zend/zend_language_parser.y

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php test/repro-maintainer/parity_reassign_this.php; echo zend:$?
php bin/vm.php test/repro-maintainer/parity_reassign_this.php; echo vm:$?
'

Engine	Output	exit
Zend	Fatal error: Cannot re-assign $this	255
VM	prints reassigned	0

Repro script: test/repro-maintainer/parity_reassign_this.php

Scope (this repo)

Area	Files
Compiler	lib/Compiler.php / CFG builder — reject $this as assignment target in user functions
VM	belt-and-suspenders runtime guard if compile path missed
Tests	test/compliance/cases/language/reassign_this.phpt

Done when

• Repro fails at compile time with Zend message (VM + JIT + AOT)
• Legitimate $this reads/writes to properties still work
• ./script/ci-fast.sh --filter reassign_this green

Links

• Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

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

[PurHur]

Merged via #4869.

Verification: issue repro — Zend and VM both exit 255 with Cannot re-assign $this; vendor/bin/phpunit --filter ReassignThisCompileTest and --filter reassign_this green in Docker.