diff --git a/composer.json b/composer.json
index 2582bd0..341cc7c 100644
--- a/composer.json
+++ b/composer.json
@@ -19,7 +19,7 @@
     "phpunit/phpunit": "^9.4.2",
     "slevomat/coding-standard": "^6.4.1",
     "squizlabs/php_codesniffer": "^3.5.0",
-    "bonami/collections": "^0.3"
+    "bonami/collections": "dev-jm-phpstan-1.0"
   },
   "config": {
     "bin-dir": "bin"
diff --git a/extension.neon b/extension.neon
index 50c9956..8b236ae 100644
--- a/extension.neon
+++ b/extension.neon
@@ -1,4 +1,8 @@
 services:
+	-
+		class: Bonami\Collection\Phpstan\ArrayListWithoutNullsReturnTypeExtension
+		tags:
+			- phpstan.broker.dynamicMethodReturnTypeExtension
 	-
 		class: Bonami\Collection\Phpstan\LateStaticBindingStaticMethodReturnTypeExtension
 		factory: Bonami\Collection\Phpstan\LateStaticBindingStaticMethodReturnTypeExtension::forMethods('Bonami\Collection\ArrayList', ['fromEmpty', 'of', 'fill', 'fromIterable'])
@@ -21,7 +25,7 @@ services:
 			- phpstan.broker.dynamicMethodReturnTypeExtension
 	-
 		class: Bonami\Collection\Phpstan\LateStaticBindingStaticMethodReturnTypeExtension
-		factory: Bonami\Collection\Phpstan\LateStaticBindingStaticMethodReturnTypeExtension::forMethods('Bonami\Collection\LazyList', ['fill', 'fromEmpty', 'fromArray', 'fromTraversable', 'fromIterable', 'of'])
+		factory: Bonami\Collection\Phpstan\LateStaticBindingStaticMethodReturnTypeExtension::forMethods('Bonami\Collection\LazyList', ['fill', 'fromEmpty', 'fromArray', 'fromIterable', 'of'])
 		tags:
 			- phpstan.broker.dynamicStaticMethodReturnTypeExtension
 	-
diff --git a/phpstan.neon b/phpstan.neon
index 43916cf..9cc4f44 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -1,9 +1,8 @@
 includes:
     - extension.neon
 parameters:
-    inferPrivatePropertyTypeFromConstructor: true
     reportUnmatchedIgnoredErrors: true
-    level: 8
+    level: 9
     paths:
         - src/
         - tests/
diff --git a/src/Bonami/Collection/Phpstan/ArrayListWithoutNullsReturnTypeExtension.php b/src/Bonami/Collection/Phpstan/ArrayListWithoutNullsReturnTypeExtension.php
new file mode 100644
index 0000000..ebee986
--- /dev/null
+++ b/src/Bonami/Collection/Phpstan/ArrayListWithoutNullsReturnTypeExtension.php
@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Bonami\Collection\Phpstan;
+
+use Bonami\Collection\ArrayList;
+use PhpParser\Node\Expr\MethodCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\MethodReflection;
+use PHPStan\Type\DynamicMethodReturnTypeExtension;
+use PHPStan\Type\Generic\GenericObjectType;
+use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
+
+class ArrayListWithoutNullsReturnTypeExtension implements DynamicMethodReturnTypeExtension
+{
+
+    public function getClass(): string
+    {
+        return ArrayList::class;
+    }
+
+    public function isMethodSupported(MethodReflection $methodReflection): bool
+    {
+        return $methodReflection->getName() === 'withoutNulls';
+    }
+
+    public function getTypeFromMethodCall(
+        MethodReflection $methodReflection,
+        MethodCall $methodCall,
+        Scope $scope
+    ): Type {
+        $type = $scope->getType($methodCall->var);
+
+        $declaringClassReflection = $methodReflection->getDeclaringClass();
+        $referencedClasses = $type->getReferencedClasses();
+
+        if (in_array(ArrayList::class, $referencedClasses, true)) {
+            $types = $declaringClassReflection->typeMapToList(
+                $declaringClassReflection->getTemplateTypeMap()->resolveToBounds()
+            );
+
+            return new GenericObjectType(
+                $declaringClassReflection->getName(),
+                array_map(static function (Type $type) {
+                    return TypeCombinator::removeNull($type);
+                }, $types)
+            );
+        }
+
+        return $type;
+    }
+}
diff --git a/src/Bonami/Collection/Phpstan/GroupByMethodReturnTypeExtension.php b/src/Bonami/Collection/Phpstan/GroupByMethodReturnTypeExtension.php
index 20bdae1..913e840 100644
--- a/src/Bonami/Collection/Phpstan/GroupByMethodReturnTypeExtension.php
+++ b/src/Bonami/Collection/Phpstan/GroupByMethodReturnTypeExtension.php
@@ -18,6 +18,7 @@
 
 class GroupByMethodReturnTypeExtension implements DynamicMethodReturnTypeExtension
 {
+    /** @var string */
     private $class;
 
     public function __construct(string $class)
diff --git a/src/Bonami/Collection/Phpstan/LateStaticBindingMethodReturnTypeExtension.php b/src/Bonami/Collection/Phpstan/LateStaticBindingMethodReturnTypeExtension.php
index 98b2903..3162ce4 100644
--- a/src/Bonami/Collection/Phpstan/LateStaticBindingMethodReturnTypeExtension.php
+++ b/src/Bonami/Collection/Phpstan/LateStaticBindingMethodReturnTypeExtension.php
@@ -12,6 +12,7 @@
 
 class LateStaticBindingMethodReturnTypeExtension implements DynamicMethodReturnTypeExtension
 {
+    /** @var string */
     private $class;
 
     /** @var array<string, int> */
diff --git a/src/Bonami/Collection/Phpstan/LateStaticBindingStaticMethodReturnTypeExtension.php b/src/Bonami/Collection/Phpstan/LateStaticBindingStaticMethodReturnTypeExtension.php
index 5c77507..de94871 100644
--- a/src/Bonami/Collection/Phpstan/LateStaticBindingStaticMethodReturnTypeExtension.php
+++ b/src/Bonami/Collection/Phpstan/LateStaticBindingStaticMethodReturnTypeExtension.php
@@ -15,6 +15,7 @@
 
 class LateStaticBindingStaticMethodReturnTypeExtension implements DynamicStaticMethodReturnTypeExtension
 {
+    /** @var string */
     private $class;
 
     /** @var array<string, int> */
diff --git a/tests/Bonami/Collection/Phpstan/ArrayListTest.php b/tests/Bonami/Collection/Phpstan/ArrayListTest.php
index b8ab0ed..da05b87 100644
--- a/tests/Bonami/Collection/Phpstan/ArrayListTest.php
+++ b/tests/Bonami/Collection/Phpstan/ArrayListTest.php
@@ -143,11 +143,15 @@ public function testSliceReturnType(): void
 
     public function testWithoutNullsReturnType(): void
     {
-        $genericList = ArrayList::fromIterable([new Foo()])->withoutNulls();
+        /** @var iterable<int, Foo|null> $iterable */
+        $iterable = [new Foo(), null];
+        /** @var ArrayList<Foo|null> $list */
+        $list = ArrayList::fromIterable($iterable);
+        $genericList = $list->withoutNulls();
         $this->requireArrayListOfFoo($genericList->withoutNulls());
         self::assertInstanceOf(ArrayList::class, $genericList);
 
-        $concreteList = FooArrayList::fromIterable([new Foo()])->withoutNulls();
+        $concreteList = FooArrayList::fromIterable($iterable)->withoutNulls();
         $this->requireFooList($concreteList->withoutNulls());
         self::assertInstanceOf(FooArrayList::class, $concreteList);
     }
diff --git a/tests/Bonami/Collection/Phpstan/LazyListTest.php b/tests/Bonami/Collection/Phpstan/LazyListTest.php
index 16bfe8f..0e34a83 100644
--- a/tests/Bonami/Collection/Phpstan/LazyListTest.php
+++ b/tests/Bonami/Collection/Phpstan/LazyListTest.php
@@ -44,17 +44,6 @@ public function testFromArrayReturnType(): void
         self::assertInstanceOf(FooLazyList::class, $concreteList);
     }
 
-    public function testFromTraversableReturnType(): void
-    {
-        $genericList = LazyList::fromTraversable(new ArrayIterator([new Foo()]));
-        $this->requireLazyListOfFoo($genericList);
-        self::assertInstanceOf(LazyList::class, $genericList);
-
-        $concreteList = FooLazyList::fromTraversable(new ArrayIterator([new Foo()]));
-        $this->requireFooList($concreteList);
-        self::assertInstanceOf(FooLazyList::class, $concreteList);
-    }
-
     public function testFromIterableReturnType(): void
     {
         $genericList = LazyList::fromIterable([new Foo()]);