Also warn about ?? on $this->prop when property has a default value

For $this->prop access on native-typed properties with a default value,
the property is always initialized so ?? on non-nullable types is useless.
Only skip the warning for $this->prop when the property has no default
value (could be uninitialized).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

src/Rules/IssetCheck.php

@@ -182,14 +182,6 @@ static function (Type $type) use ($typeMessageCallback): ?string {
 				}
 
 				if (!$scope->hasExpressionType($expr)->yes()) {
-					if (
-						$expr instanceof Node\Expr\PropertyFetch
-						&& $expr->var instanceof Expr\Variable
-						&& $expr->var->name === 'this'
-					) {
-						return $this->checkUndefined($expr->var, $scope, $operatorDescription, $identifier);
-					}
-
 					if ($expr instanceof Node\Expr\StaticPropertyFetch) {
 						if ($expr->class instanceof Expr) {
 							return $this->checkUndefined($expr->class, $scope, $operatorDescription, $identifier);

tests/PHPStan/Rules/Variables/NullCoalesceRuleTest.php

@@ -373,6 +373,10 @@ public function testBug13921(): void
 	public function testBug14393(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-14393.php'], [
+			[
+				'Property Bug14393\MyClass::$i (int) on left side of ?? is not nullable.',
+				11,
+			],
 			[
 				'Property Bug14393\MyClass::$i (int) on left side of ?? is not nullable.',
 				27,