Fix type narrowed too much after identical comparison with never-typed generic method

[phpstan-bot]

Summary

Fixes phpstan/phpstan#14281

When a generic class like Collection<TElement> is constructed with an empty array default (new TestCollection()), the template TElement resolves to never. This causes method return types like TElement|null to collapse to null. Subsequent assert($data[0] === $collection->get(0)) comparisons are then seen as always-false (e.g. 0 === null), making code unreachable and narrowing $data to *NEVER*.

Root cause

In ResolvedFunctionVariantWithOriginal::resolveResolvableTemplateTypes(), class-level template types that resolve to never were used literally in method return types. For the object type itself (TestCollection<never>), this is correct — never is the bottom type and passes covariance checks. But for method return types, it produces overly narrow types that break type narrowing in the caller.

Fix

When resolving class-level template types in method return types, if the resolved type is never, replace it with the template's declared bound (e.g. mixed for unbounded, stdClass for @template T of stdClass). This is skipped when the return type contains ConditionalType nodes, since conditional return types like (T is never ? false : bool) need the actual never value to evaluate correctly.

Changed files

• src/Reflection/ResolvedFunctionVariantWithOriginal.php — the fix
• tests/PHPStan/Analyser/nsrt/bug-14281.php — regression test
• tests/PHPStan/Analyser/nsrt/generics.php — updated assertion: empty StdClassCollection now returns array<stdClass> from getAll() instead of array{}, reflecting the template bound instead of never

Impact

• Collection<never>::get() now returns mixed (bound) instead of null (never|null)
• StdClassCollection<never, never>::getAll() now returns array<stdClass> instead of array{}
• Conditional return types like (T is never ? false : bool) are preserved unchanged
• All 11,869 tests pass, PHPStan self-analysis clean