Fix #11687: Method call on unioned class type analysis is broken

[phpstan-bot]

Summary

When calling a static method that returns static on a union of class types (e.g., $clUnioned::retStatic() where $clUnioned is class-string<A>|class-string<X>), PHPStan incorrectly resolved the static return type to the entire union instead of just the class that declares the method. This caused A::retStatic() (returning static) to resolve as A|X instead of just A.

Changes

• Modified src/Type/UnionType.php in getUnresolvedMethodPrototype(): stopped calling withCalledOnType($this) for non-template union types. Each member type now keeps its own called-on type, so static resolves correctly per-class.
• Template union types (TemplateUnionType, TemplateBenevolentUnionType) still pass the full union as the called-on type, preserving template type identity (e.g., T of DateTime|DateTimeImmutable stays as the template type rather than being split).
• Updated expected assertion in tests/PHPStan/Analyser/nsrt/static-late-binding.php from bool|StaticLateBinding\A|StaticLateBinding\X to bool|StaticLateBinding\A.
• Added regression test tests/PHPStan/Analyser/nsrt/bug-11687.php.

Root cause

In UnionType::getUnresolvedMethodPrototype(), each member type's method prototype had its calledOnType overridden with the full union via ->withCalledOnType($this). Later, in CalledOnTypeUnresolvedMethodPrototypeReflection::transformStaticType(), when a StaticType was encountered in a method's return type, it was replaced with $this->calledOnType — the full union. This meant A::retStatic() returning static(A) would become A|X instead of just A.

The fix conditionally applies withCalledOnType($this) only when the union is a TemplateType (i.e., TemplateUnionType or TemplateBenevolentUnionType), where preserving the full union/template identity is correct. For plain unions, each member keeps its own type as the called-on type.

Test

Added tests/PHPStan/Analyser/nsrt/bug-11687.php which tests:

• A::retStaticConst() returns int
• X::retStaticConst() returns bool
• $clUnioned::retStaticConst() returns bool|int (correct, no static involved)
• A::retStatic() returns A (uses @return static)
• X::retStatic() returns bool
• $clUnioned::retStatic() returns bool|A (previously was bool|A|X)

Fixes phpstan/phpstan#11687

Closes phpstan/phpstan#12562