Fix isset() type narrowing lost when result stored in variable for property access

- Extended processSureTypesForConditionalExpressionsAfterAssign and
  processSureNotTypesForConditionalExpressionsAfterAssign to store conditional
  expressions for PropertyFetch, ArrayDimFetch, and StaticPropertyFetch in
  addition to Variable expressions
- Previously, when `$notEmpty = isset($a->worlds[0])` was used in a condition
  like `if ($notEmpty && $a->worlds[0]->x === 1)`, the type narrowing for
  `$a->worlds` (HasOffsetType) was discarded because only Variable expressions
  were stored as conditional expressions
- New regression test in tests/PHPStan/Rules/Arrays/data/bug-12574c.php

Closes phpstan/phpstan#12574

Author: phpstan-bot

src/Analyser/NodeScopeResolver.php

@@ -6776,14 +6776,19 @@ private function unwrapAssign(Expr $expr): Expr
 	private function processSureTypesForConditionalExpressionsAfterAssign(Scope $scope, string $variableName, array $conditionalExpressions, SpecifiedTypes $specifiedTypes, Type $variableType): array
 	{
 		foreach ($specifiedTypes->getSureTypes() as $exprString => [$expr, $exprType]) {
-			if (!$expr instanceof Variable) {
-				continue;
-			}
-			if (!is_string($expr->name)) {
-				continue;
-			}
+			if ($expr instanceof Variable) {
+				if (!is_string($expr->name)) {
+					continue;
+				}
 
-			if ($expr->name === $variableName) {
+				if ($expr->name === $variableName) {
+					continue;
+				}
+			} elseif (
+				!$expr instanceof PropertyFetch
+				&& !$expr instanceof ArrayDimFetch
+				&& !$expr instanceof StaticPropertyFetch
+			) {
 				continue;
 			}
 
@@ -6810,14 +6815,19 @@ private function processSureTypesForConditionalExpressionsAfterAssign(Scope $sco
 	private function processSureNotTypesForConditionalExpressionsAfterAssign(Scope $scope, string $variableName, array $conditionalExpressions, SpecifiedTypes $specifiedTypes, Type $variableType): array
 	{
 		foreach ($specifiedTypes->getSureNotTypes() as $exprString => [$expr, $exprType]) {
-			if (!$expr instanceof Variable) {
-				continue;
-			}
-			if (!is_string($expr->name)) {
-				continue;
-			}
+			if ($expr instanceof Variable) {
+				if (!is_string($expr->name)) {
+					continue;
+				}
 
-			if ($expr->name === $variableName) {
+				if ($expr->name === $variableName) {
+					continue;
+				}
+			} elseif (
+				!$expr instanceof PropertyFetch
+				&& !$expr instanceof ArrayDimFetch
+				&& !$expr instanceof StaticPropertyFetch
+			) {
 				continue;
 			}
 

tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php

@@ -1038,6 +1038,13 @@ public function testBug12574b(): void
 		$this->analyse([__DIR__ . '/data/bug-12574b.php'], []);
 	}
 
+	public function testBug12574c(): void
+	{
+		$this->reportPossiblyNonexistentGeneralArrayOffset = true;
+
+		$this->analyse([__DIR__ . '/data/bug-12574c.php'], []);
+	}
+
 	public function testBug12926(): void
 	{
 		$this->reportPossiblyNonexistentGeneralArrayOffset = true;

tests/PHPStan/Rules/Arrays/data/bug-12574c.php

@@ -0,0 +1,32 @@
+<?php declare(strict_types = 1);
+
+namespace Bug12574c;
+
+class Galaxy
+{
+	/** @var list<World> $worlds */
+	public array $worlds = [];
+}
+
+class World
+{
+	public int $x = 1;
+}
+
+
+function hello(Galaxy $a): void
+{
+	$notEmpty = isset($a->worlds[0]);
+	if ($notEmpty && $a->worlds[0]->x === 1) {
+		echo 'hello';
+	}
+}
+
+function hello2(Galaxy $a): void
+{
+	$worlds = $a->worlds;
+	$notEmpty = isset($worlds[0]);
+	if ($notEmpty && $worlds[0]->x === 1) {
+		echo 'hello';
+	}
+}