fix(preprocessor): reject variadic promoted properties and callable property/constant types

[AlessioGiacobbe]

Two declaration gaps: variadic promoted constructor properties (__construct(public int ...$x)) compiled — the promotion was registered before the variadic check (Zend: "Cannot declare variadic promoted property") — and callable in property types (declared, promoted, union members) and class/interface constant types was accepted, where Zend rejects it ("Property A::$x cannot have type callable"; constants previously failed only incidentally with a confusing default-value error).

Messages include the full type string for composite types. Each rule probed against Zend 8.4.13.

Part of the split of #39.

[matyhtf]

typeDeclContainsCallable() deliberately returns false for every IntersectionType, but there is no merged fallback check on current master. A callable nested in DNF therefore reaches gen_stub.php and crashes on an assertion instead of producing a compiler diagnostic:

class Bag {
    public (Traversable&callable)|stdClass $value;
}

Current result: AssertionError: assert(!$type->isBuiltin) in StubType::getDnfTypeDeclarations(). Zend rejects this at the declaration (Type callable cannot be part of an intersection type). The same gap applies to typed class constants and interface properties/constants.

Please make this PR safe independently: recurse into intersection members and reject callable with a stable fatal diagnostic, or rebase after the generic compound-type validator is merged and add explicit DNF callable tests proving the assertion is unreachable. The focused tests currently pass (5/5), but only cover bare and top-level union forms.

[AlessioGiacobbe]

Fixed. Probing showed Zend rejects callable while compiling the intersection type itself, in every declaration context, with "Type callable cannot be part of an intersection type" — and that this wins over the property-specific ban (callable|(Traversable&callable) reports the intersection error). So instead of teaching typeDeclContainsCallable() to return the wrong (property) diagnostic for intersections, a dedicated walk over nullable/union/intersection members now runs before the existing callable checks at all four guard sites (class constants, declared + promoted properties, interface constants, interface properties).

Your exact case flips from the gen_stub assert(!$type->isBuiltin) crash to Zend's diagnostic; bare intersections, second-DNF-member, promoted, constant and interface variants are all covered, and a callable-free DNF ((Countable&Traversable)|stdClass) still compiles — proving the assertion is unreachable without over-rejection. 7 new fixtures, 31/31 focused tests green.

[matyhtf]

Please rebase this branch onto the latest master; #45, #52, #59, #63, and #66 have now been merged.

assertTypeDeclIntersectionsHaveNoCallable() is currently invoked only from property and class/interface constant paths. The same invalid type in a function parameter or return declaration still bypasses this check and can reach the later generator path:

function consume(Traversable&callable $value): void {}
function produce(): Traversable&callable {}

Zend rejects both while compiling the type with Type callable cannot be part of an intersection type.

Please move this rule into the common type-declaration validation path used by parameters, returns, properties, promoted properties, class constants, interface members, and closures, rather than maintaining repeated per-context calls. Add negative parameter and return tests, including callable inside a DNF member.

[AlessioGiacobbe]

Rebased onto current master. The rule now lives on the common path:

• assertTypeDeclIntersectionsHaveNoCallable() moved into parseTypeDecl() (behind resolveTypeDecl()), the funnel that parameters, returns, properties, promoted properties, class constants, interface constants and interface hooked properties all reach; the four per-context calls are removed. The diagnostic text matches Zend: Type callable cannot be part of an intersection type, anchored at the offending member node.
• Closures and arrow functions previously never resolved their full type nodes, so doGenClosure() now routes their parameter and return declarations through resolveTypeDecl() as well.
• The separate bare/nullable/union callable property/constant bans remain distinct rules (as in Zend), but resolveTypeDecl() is hoisted above them so callable|(Traversable&callable) reports the intersection conflict first, matching Zend's precedence.

Tests (each verified against Zend 8.4.13 first): negative parameter Traversable&callable, negative return, DNF member (Traversable&callable)|stdClass in a parameter, closure parameter and closure return; positive bare-callable parameter stays accepted.