NodeScopeResolver: do not reassign objects as arrays on ArrayDimFetch

this fixes phpstan/phpstan#3782.
I'm not sure if this may have any side effects, but I can't see any circumstances where it makes sense to reassign an object as an array on array dim fetch.

Author: dktapps

src/Analyser/NodeScopeResolver.php

@@ -97,6 +97,7 @@
 use PHPStan\Type\MixedType;
 use PHPStan\Type\NullType;
 use PHPStan\Type\ObjectType;
+use PHPStan\Type\ObjectWithoutClassType;
 use PHPStan\Type\StaticType;
 use PHPStan\Type\StringType;
 use PHPStan\Type\Type;
@@ -2379,7 +2380,7 @@ private function processAssignVar(
 			$scope = $result->getScope();
 
 			$varType = $scope->getType($var);
-			if (!(new ObjectType(\ArrayAccess::class))->isSuperTypeOf($varType)->yes()) {
+			if (!(new ObjectWithoutClassType())->isSuperTypeOf($varType)->yes()) {
 				// 4. compose types
 				if ($varType instanceof ErrorType) {
 					$varType = new ConstantArrayType([], []);

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -10048,6 +10048,11 @@ public function dataBug2899(): array
 		return $this->gatherAssertTypes(__DIR__ . '/data/bug-2899.php');
 	}
 
+	public function dataBug3782(): array
+	{
+		return $this->gatherAssertTypes(__DIR__ . '/data/bug-3782.php');
+	}
+
 	/**
 	 * @dataProvider dataBug2574
 	 * @dataProvider dataBug2577
@@ -10116,6 +10121,7 @@ public function dataBug2899(): array
 	 * @dataProvider dataBug3133
 	 * @dataProvider dataBug2550
 	 * @dataProvider dataBug2899
+	 * @dataProvider dataBug3782
 	 * @param string $assertType
 	 * @param string $file
 	 * @param mixed ...$args

tests/PHPStan/Analyser/data/bug-3782.php

@@ -0,0 +1,26 @@
+<?php declare(strict_types = 1);
+
+namespace Bug3782;
+
+use function PHPStan\Analyser\assertType;
+
+class HelloWorld
+{
+	/** @param mixed[] $data */
+	public function sayHello(array $data): void
+	{
+		foreach($data as $key => $value){
+			$this[$key] = $value;
+			assertType('$this(Bug3782\\HelloWorld)', $this);
+		}
+	}
+
+	public static function sayHello2(array $data): void
+	{
+		$var = new HelloWorld();
+		foreach ($data as $key => $value){
+			$var[$key] = $value;
+			assertType('Bug3782\\HelloWorld', $var);
+		}
+	}
+}