Language: PHP 8 attributes (#[Attr] on classes, methods, properties)

[PurHur]

Problem

PHP 8 attributes (#[Route('/home')], #[\AllowDynamicProperties]) appear in modern frameworks and on paths toward self-host (vendor/php-cfg may carry attribute nodes). The compiler today does not lower attributes — lint may reject decorated declarations or php-cfg may drop metadata silently.

Wave 3 finish line #1751 tracks landing this with #1360, #1366, #1378.

Goal (minimum viable v1)

1. Parse attribute groups on classes, methods, properties, parameters, constants (host php-parser already tokenizes on PHP 8.2+ — Dependencies: php-parser token map for PHP 8.2+ host runs #113).
2. Store attribute AST on CFG/class metadata (or attach to Compiler symbol table).
3. Runtime: ignore attributes for execution (PHP allows unused attributes) OR expose read-only via future reflection stub.
4. Lint: remove UnsupportedRegistry block when VM accepts decorated declarations.

Defer: JIT/AOT attribute reflection, compile-time #[\Attribute] validation, enum attribute targets.

Implementation hints

Layer	Files	Notes
Parser	vendor/nikic/php-parser	AttributeGroup, Attribute nodes on PHP 8.2 host
CFG	php-cfg / lib/Compiler.php	Preserve attribute list on Class_, ClassMethod, Property
VM	lib/VM.php	Strip before dispatch or store on class metadata bag
Lint	lib/Lint/UnsupportedRegistry.php	Map until VM lands
Self-host	SelfHostBuiltinPolicy	No-op if vendor uses attributes only for static analysis
Docs	docs/capabilities-syntax.md	Regenerate via php script/capability-syntax.php

Tests

• test/compliance/cases/attribute_class.phpt — class with #[\AllowDynamicProperties] instantiates
• test/compliance/cases/attribute_method.phpt — method attribute ignored at runtime
• test/unit/AttributeParseTest.php — lint green on decorated stub

Unblock order

1. Host parser tokens (Dependencies: php-parser token map for PHP 8.2+ host runs #113 if 8.1 host fails)
2. CFG carry-through in Compiler::compileClass
3. VM ignore semantics + compliance PHPT
4. JIT: document deferral in capability matrix (like intersection types Language: Intersection types (A&B) in parameters and properties #1357)

Acceptance criteria

./phpc lint -r '#[\AllowDynamicProperties] class C {}'
./phpc run -r '#[\AllowDynamicProperties] class C {} new C(); echo "ok";'
./script/ci-fast.sh --filter Attribute

Docker:

docker run --rm -v "$(pwd):/compiler" -w /compiler php-compiler:22.04-dev \
  ./script/ci-fast.sh --filter Attribute

No GitHub Actions.

Dependencies

• Dependencies: php-parser token map for PHP 8.2+ host runs #113 — php-parser token map on PHP 8.2+ host runs
• Roadmap wave 3: full PHP language + stdlib gaps tracker (#1354–#1379) #1380 / Wave 3 close-out: land remaining language + debug_backtrace (#1380 finish line) #1751 — wave 3 close-out
• Orthogonal: full reflection API (not required v1)

Links

• ROADMAP 🗺️ ROADMAP: Compile a small PHP web application (living document) #78 Phase 1 Language
• Related backlog Language features wave 2: JIT/syntax gaps tracker (#1222–#1235) #1238
• docs/capabilities-syntax.md

[PurHur]

Still open — no PR on remote. Remaining wave-3 language item without an active branch.