Address both review findings on the trait composition fix:
1. An abstract trait requirement was discarded without validating the
concrete implementation. composeTraitAst now validates the
implementation - the class's own method, a concrete method from
another trait (in either collection order), or a class method
matching an aliased abstract - against the abstract declaration
before dropping it, following Zend's trait-composition rules:
matching staticness, a kept by-reference return, no additional
required parameters, contravariant parameter types, and a covariant
return type. Type variance reuses the existing override-check
machinery on the preprocessed definitions; late-bound self/static/
parent keywords are unified through the recorded type keywords, and
self-in-trait resolutions are remapped to the consuming class.
Visibility is intentionally not restricted: Zend allows an
implementation of any visibility to fulfill an abstract trait
requirement (verified against Zend 8.4).
2. Multiple alias adaptations of the same method depended on source
order because a same-name visibility change mutated the statement
that later adaptations cloned. Every adaptation now derives its
flags from the immutable original flags, and the original statement
is only mutated after all adaptations are processed, so
`value as protected; value as alias;` leaves `alias` public in both
adaptation orders (matching Zend, where each adaptation derives from
the original and the last same-name adaptation wins).
Both behaviors were pinned against Zend PHP 8.4 before implementing.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Alessio Giacobbe