[yoeunes]

Stacked on #3.

What

The capturing groups and the whole match now take their types from the capture shape analysis the parser computes beside the patterns it reads. Only the topology stays in RegexGroupParser: which group sits in which branch of which alternation, under which optional quantifier.

Topology rules that mirror what the matcher folds:

• an optional quantifier marks the one node it wraps, and only that one — a group further below learns its optionality from its parent chain;
• a capturing parent carries its optionality to its children;
• a group a (?(DEFINE)...) block defines holds the empty string alone: it is numbered, it is optional, and nothing more is true of it;
• the branches of a conditional run one at a time and are read as exclusive as an alternation's, and a lookaround condition counts its groups before them.

The subject narrows on its own channel. $matches[0] is the match the engine wrote, constants included; the subject merely contains the match, so it narrows to the accessories the match leaves open — never to the match's constants or digits, and $ admits one final newline ("a\n" matches /^(a|b|c)$/).

Against the engine

PHPRegexBackendParityTest matches every pattern family for real and checks what preg_match() writes into $matches against the shape: the group count, the values, the optionality of what the engine leaves unset. About 200 assertions across 17 nsrt fixtures re-pin what the sharper shapes read:

• constant unions for literals and alternations ('a'|'b'|'c', 'foobar'|'foobarbaz');
• numeric-string for digit runs, '0'|'1'|…|'9' for single digits;
• non-falsy-string where a mandatory neighbour pins the value off zero (3(/.*)?, (c(\d+)?)?, (\w+)z);
• the empty string alone where a zero-width first branch wins the match ((^|foo) reads '').

NodeScopeResolverTest: 1879/1879. Static analysis of the repository: 0 errors. Known imprecision, documented here rather than hidden: a lone (?(DEFINE)...) group renders as a union of the empty match and the match with the defined group at '' — both arms true, the second never taken by the engine.

Packaging

The Hoa retreat's residue leaves with this pull request too: the autoload fix in bin/phpstan, the scoper stub and the Hoa prefix exclusion. The shapes cache on the judged engine, and the ignored-error validator reads its patterns with their modifiers, so /x patterns in ignoreErrors no longer read as if their blanks were literal.

[yoeunes]

Folded into #1: the stack now travels as one pull request while the series is being built. The branch content is unchanged — read-regex-shapes-through-phpregex points at the same commits.