Narrow type on setting offsets of properties

src/Analyser/NodeScopeResolver.php

@@ -5344,9 +5344,17 @@ private function processAssignVar(
 			$originalVar = $var;
 			$assignedPropertyExpr = $assignedExpr;
 			while ($var instanceof ArrayDimFetch) {
-				$varForSetOffsetValue = $var->var;
-				if ($varForSetOffsetValue instanceof PropertyFetch || $varForSetOffsetValue instanceof StaticPropertyFetch) {
-					$varForSetOffsetValue = new OriginalPropertyTypeExpr($varForSetOffsetValue);
+				if (
+					$var->var instanceof PropertyFetch
+					|| $var->var instanceof StaticPropertyFetch
+				) {
+					if (((new ObjectType(ArrayAccess::class))->isSuperTypeOf($scope->getType($var->var))->yes())) {
+						$varForSetOffsetValue = $var->var;
+					} else {
+						$varForSetOffsetValue = new OriginalPropertyTypeExpr($var->var);
+					}
+				} else {
+					$varForSetOffsetValue = $var->var;
 				}
 				$assignedPropertyExpr = new SetOffsetValueTypeExpr(
 					$varForSetOffsetValue,
@@ -5682,9 +5690,17 @@ static function (): void {
 			$dimFetchStack = [];
 			$assignedPropertyExpr = $assignedExpr;
 			while ($var instanceof ExistingArrayDimFetch) {
-				$varForSetOffsetValue = $var->getVar();
-				if ($varForSetOffsetValue instanceof PropertyFetch || $varForSetOffsetValue instanceof StaticPropertyFetch) {
-					$varForSetOffsetValue = new OriginalPropertyTypeExpr($varForSetOffsetValue);
+				if (
+					$var->getVar() instanceof PropertyFetch
+					|| $var->getVar() instanceof StaticPropertyFetch
+				) {
+					if (((new ObjectType(ArrayAccess::class))->isSuperTypeOf($scope->getType($var->getVar()))->yes())) {
+						$varForSetOffsetValue = $var->getVar();
+					} else {
+						$varForSetOffsetValue = new OriginalPropertyTypeExpr($var->getVar());
+					}
+				} else {
+					$varForSetOffsetValue = $var->getVar();
 				}
 				$assignedPropertyExpr = new SetExistingOffsetValueTypeExpr(
 					$varForSetOffsetValue,

tests/PHPStan/Rules/Properties/TypesAssignedToPropertiesRuleTest.php

@@ -689,6 +689,28 @@ public function testBug12131(): void
 		]);
 	}
 
+	public function testBug6398(): void
+	{
+		$this->checkExplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-6398.php'], []);
+	}
+
+	public function testBug6571(): void
+	{
+		$this->checkExplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-6571.php'], []);
+	}
+
+	public function testBug12565(): void
+	{
+		if (PHP_VERSION_ID < 80000) {
+			$this->markTestSkipped('Test requires PHP 8.0.');
+		}
+
+		$this->checkExplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-12565.php'], []);
+	}
+
 	public function testShortBodySetHook(): void
 	{
 		if (PHP_VERSION_ID < 80400) {

tests/PHPStan/Rules/Properties/data/bug-12565.php

@@ -0,0 +1,50 @@
+<?php declare(strict_types = 1);
+
+namespace Bug12565;
+
+class EntryType {
+	public string $title = '';
+	public string $subTitle = '';
+}
+/**
+ * @implements \ArrayAccess<int, EntryType>
+ */
+class ArrayLike implements \ArrayAccess {
+
+	/** @var EntryType[] */
+	private array $values = [];
+	public function offsetExists(mixed $offset): bool
+	{
+		return isset($this->values[$offset]);
+	}
+
+	public function offsetGet(mixed $offset): EntryType
+	{
+		return $this->values[$offset] ?? new EntryType();
+	}
+
+	public function offsetSet(mixed $offset, mixed $value): void
+	{
+		$this->values[$offset] = $value;
+	}
+
+	public function offsetUnset(mixed $offset): void
+	{
+		unset($this->values[$offset]);
+	}
+}
+
+class Wrapper {
+	public ?ArrayLike $myArrayLike;
+
+	public function __construct()
+	{
+		$this->myArrayLike = new ArrayLike();
+
+	}
+}
+
+$baz = new Wrapper();
+$baz->myArrayLike = new ArrayLike();
+$baz->myArrayLike[1] = new EntryType();
+$baz->myArrayLike[1]->title = "Test";

tests/PHPStan/Rules/Properties/data/bug-6398.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace Bug6398;
+
+class AsyncTask{
+	/**
+	 * @phpstan-var \ArrayObject<int, array<string, mixed>>|null
+	 */
+	private static $threadLocalStorage = null;
+
+	/**
+	 * @param mixed  $complexData the data to store
+	 */
+	protected function storeLocal(string $key, $complexData) : void{
+		if(self::$threadLocalStorage === null){
+			self::$threadLocalStorage = new \ArrayObject();
+		}
+		self::$threadLocalStorage[spl_object_id($this)][$key] = $complexData;
+	}
+
+	/**
+	 * @return mixed
+	 */
+	protected function fetchLocal(string $key){
+		$id = spl_object_id($this);
+		if(self::$threadLocalStorage === null or !isset(self::$threadLocalStorage[$id][$key])){
+			throw new \InvalidArgumentException("No matching thread-local data found on this thread");
+		}
+
+		return self::$threadLocalStorage[$id][$key];
+	}
+}

tests/PHPStan/Rules/Properties/data/bug-6571.php

@@ -0,0 +1,31 @@
+<?php declare(strict_types = 1); // lint >= 7.4
+
+namespace Bug6571;
+
+interface ClassLoader{}
+
+class HelloWorld
+{
+	/** @var \Threaded|\ClassLoader[]|null  */
+	private ?\Threaded $classLoaders = null;
+
+	/**
+	 * @param \ClassLoader[] $autoloaders
+	 */
+	public function setClassLoaders(?array $autoloaders = null) : void{
+		if($autoloaders === null){
+			$autoloaders = [];
+		}
+
+		if($this->classLoaders === null){
+			$this->classLoaders = new \Threaded();
+		}else{
+			foreach($this->classLoaders as $k => $autoloader){
+				unset($this->classLoaders[$k]);
+			}
+		}
+		foreach($autoloaders as $autoloader){
+			$this->classLoaders[] = $autoloader;
+		}
+	}
+}