Pointcut expressiveness gaps for modern type/modifier system (union/DNF return types, readonly/private(set)/final)

[lisachenko]

Summary

Two pointcut components lag behind the modern PHP type/modifier system. Neither breaks weaving — matching is just silently impossible or wrong for these constructs. From the PHP 8.5 support audit (PR #597).

1. ReturnTypePointcut cannot match union / intersection / DNF types

src/Aop/Pointcut/ReturnTypePointcut.php:27-29 documents it:

This implementation currently doesn't support properly matching of complex types, thus union/intersection/DNF types are not supported yet here.

Matching is a string compare + wildcard on (string) $reflector->getReturnType() (line ~76), so execution(public **->*(*): Iterator) never matches Iterator|Generator, and member order (A&B vs B&A) defeats exact matches.

Proposed: normalize both sides into sorted member sets (split on | at depth 0, & inside parens), and let a single-type pattern match if any union member matches; document the semantics chosen.

2. ModifierPointcut has no predicates for modern modifiers

src/Aop/Pointcut/ModifierPointcut.php matches only the classic IS_PUBLIC/IS_PROTECTED/IS_PRIVATE/IS_STATIC/IS_FINAL/IS_ABSTRACT bitmask, and src/Aop/Pointcut/PointcutGrammar.php only accepts public|protected|private|final keywords. Not expressible today:

• readonly properties/classes (8.1/8.2)
• asymmetric visibility private(set) / protected(set) (8.4; static asymmetric visibility in 8.5)
• hooked vs plain properties (8.4)
• final properties (8.4)

Proposed: extend the grammar with readonly, private(set), protected(set) modifier tokens mapped onto the corresponding ReflectionProperty predicates (isReadOnly(), isPrivateSet(), isProtectedSet(), isFinal()), with the existing matcher-gate caveat that readonly/hooked/static properties are excluded from access() interception anyway (useful mainly for negative filters and class filters).