Skip raw generic ObjectType method/property prototype when GenericObjectType ancestor is present in IntersectionType

[phpstan-bot]

Summary

When an intersection type like Datagrid&DatagridInterface<Proxy> is formed (e.g. via assert($x instanceof Datagrid) on a DatagridInterface<Proxy>), calling a method like getPager() previously returned *NEVER* instead of the expected PagerInterface<Proxy>.

Root cause

IntersectionTypeMethodReflection::getVariants() intersects return types from all types in the intersection that provide the method. When a raw (unparameterized) ObjectType for a generic class is part of the intersection alongside a GenericObjectType of its ancestor:

1. The raw ObjectType('Datagrid') resolves its template parameters to their bounds (e.g. T → ProxyQueryInterface), so getPager() returns PagerInterface<ProxyQueryInterface>
2. The GenericObjectType('DatagridInterface', [Proxy]) resolves templates to the specific type args, so getPager() returns PagerInterface<Proxy>
3. TypeCombinator::intersect(PagerInterface<ProxyQueryInterface>, PagerInterface<Proxy>) returns never because PagerInterface is invariant in T and ProxyQueryInterface !== Proxy

The underlying method is the same (inherited from DatagridInterface), so intersecting two different resolutions of the same method's return type is incorrect.

Changes

• src/Type/IntersectionType.php:
  • In getUnresolvedMethodPrototype(): skip the raw ObjectType's prototype when a GenericObjectType ancestor that also declares the method is present in the intersection
  • In getUnresolvedInstancePropertyPrototype(): same fix for instance properties
  • In getUnresolvedStaticPropertyPrototype(): same fix for static properties
  • Added helper methods hasGenericAncestorWithMethodInIntersection() and hasGenericAncestorWithPropertyInIntersection() that check whether a raw generic ObjectType has a GenericObjectType ancestor in the intersection that also declares the member being accessed
• phpstan-baseline.neon: added baseline entries for the instanceof checks on internal IntersectionType members (these are valid internal checks on concrete type components)

Analogous cases probed:

• Instance properties: fixed (same pattern applied)
• Static properties: fixed (same pattern applied)
• Methods unique to the raw type (not on ancestor): verified they still resolve correctly (the skip condition requires the ancestor to also have the method)
• Both types being GenericObjectType: verified this still works correctly (the skip only applies to raw ObjectType)
• Multi-level inheritance (ChildDatagrid&DatagridInterface): tested and works

Test

Added tests/PHPStan/Analyser/nsrt/bug-5357.php with assertions covering:

• The original reproducer from the issue (assert + method call)
• Direct @param Datagrid&DatagridInterface<Proxy> annotation
• Explicit @param Datagrid<Proxy> (already worked, sanity check)
• Parent class generic intersection (ChildDatagrid&Datagrid<Proxy>)
• Grandparent interface (ChildDatagrid&DatagridInterface<Proxy>)
• Both types having explicit generics (Datagrid<Proxy>&DatagridInterface<Proxy>)
• Method unique to the raw type not affected by the skip logic

Fixes phpstan/phpstan#5357