Fix phpstan/phpstan#13920: Anonymous class causes "variable might not be defined" issue

[phpstan-bot]

Summary

When an anonymous class with an explicit constructor calling parent::__construct() was used inside a try block, PHPStan incorrectly reported that variables defined before the try block "might not be defined" in the finally block.

Changes

• Modified src/Analyser/ExprHandler/NewHandler.php to replace the scope on throw points extracted from the anonymous class constructor's statement result with the outer scope (the scope at the new expression site)
• Added replaceScope() method to src/Analyser/InternalThrowPoint.php
• Added regression test in tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php and tests/PHPStan/Rules/Variables/data/bug-13920.php

Root cause

When processing new class() extends Foo { public function __construct() { parent::__construct(); } }, the NewHandler extracted throw points from the constructor's body analysis. These throw points carried scopes from within the constructor method, which naturally didn't contain the outer method's variables. When the try/finally handling merged these throw point scopes into the finallyScope via mergeWith(), any outer variable present in the finally scope but absent from the inner constructor scope was downgraded from "definitely defined" (Yes certainty) to "might not be defined" (Maybe certainty).

The fix replaces the inner scope on these throw points with the outer $scope at the call site, matching the behavior already used for inherited constructors (the else branch at line 196, which uses getConstructorThrowPoint() with the outer scope).

Test

Added a regression test that verifies no errors are reported when a variable is defined before a try block containing an anonymous class with parent::__construct(), and that variable is used in the finally block.

Fixes phpstan/phpstan#13920