diff --git a/src/Rules/RuleLevelHelper.php b/src/Rules/RuleLevelHelper.php
index 43f57d7223..cba600b029 100644
--- a/src/Rules/RuleLevelHelper.php
+++ b/src/Rules/RuleLevelHelper.php
@@ -6,7 +6,6 @@
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\ReflectionProvider;
 use PHPStan\Type\BenevolentUnionType;
-use PHPStan\Type\CompoundType;
 use PHPStan\Type\ErrorType;
 use PHPStan\Type\Generic\TemplateMixedType;
 use PHPStan\Type\MixedType;
@@ -98,7 +97,7 @@ public function accepts(Type $acceptingType, Type $acceptedType, bool $strictTyp
 		}
 
 		$accepts = $acceptingType->accepts($acceptedType, $strictTypes);
-		if (!$accepts->yes() && $acceptingType instanceof UnionType && !$acceptedType instanceof CompoundType) {
+		if (!$accepts->yes() && $acceptingType instanceof UnionType) {
 			foreach ($acceptingType->getTypes() as $innerType) {
 				if (self::accepts($innerType, $acceptedType, $strictTypes)) {
 					return true;
diff --git a/tests/PHPStan/Rules/Functions/ReturnTypeRuleTest.php b/tests/PHPStan/Rules/Functions/ReturnTypeRuleTest.php
index af0a1ece0d..292d219563 100644
--- a/tests/PHPStan/Rules/Functions/ReturnTypeRuleTest.php
+++ b/tests/PHPStan/Rules/Functions/ReturnTypeRuleTest.php
@@ -13,16 +13,19 @@
 class ReturnTypeRuleTest extends RuleTestCase
 {
 
-	private bool $checkExplicitMixed = false;
+	private bool $checkNullables;
+
+	private bool $checkExplicitMixed;
 
 	protected function getRule(): Rule
 	{
-		return new ReturnTypeRule(new FunctionReturnTypeCheck(new RuleLevelHelper($this->createReflectionProvider(), true, false, true, $this->checkExplicitMixed, false)));
+		return new ReturnTypeRule(new FunctionReturnTypeCheck(new RuleLevelHelper($this->createReflectionProvider(), $this->checkNullables, false, true, $this->checkExplicitMixed, false)));
 	}
 
 	public function testReturnTypeRule(): void
 	{
 		require_once __DIR__ . '/data/returnTypes.php';
+		$this->checkNullables = true;
 		$this->checkExplicitMixed = false;
 		$this->analyse([__DIR__ . '/data/returnTypes.php'], [
 			[
@@ -71,6 +74,7 @@ public function testReturnTypeRule(): void
 	public function testReturnTypeRulePhp70(): void
 	{
 		$this->checkExplicitMixed = false;
+		$this->checkNullables = true;
 		$this->analyse([__DIR__ . '/data/returnTypes-7.0.php'], [
 			[
 				'Function ReturnTypes\Php70\returnInteger() should return int but empty return statement found.',
@@ -82,6 +86,7 @@ public function testReturnTypeRulePhp70(): void
 	public function testIsGenerator(): void
 	{
 		$this->checkExplicitMixed = false;
+		$this->checkNullables = true;
 		$this->analyse([__DIR__ . '/data/is-generator.php'], []);
 	}
 
@@ -89,6 +94,7 @@ public function testBug2568(): void
 	{
 		require_once __DIR__ . '/data/bug-2568.php';
 		$this->checkExplicitMixed = false;
+		$this->checkNullables = true;
 		$this->analyse([__DIR__ . '/data/bug-2568.php'], []);
 	}
 
@@ -96,6 +102,7 @@ public function testBug2723(): void
 	{
 		require_once __DIR__ . '/data/bug-2723.php';
 		$this->checkExplicitMixed = false;
+		$this->checkNullables = true;
 		$this->analyse([__DIR__ . '/data/bug-2723.php'], [
 			[
 				'Function Bug2723\baz() should return Bug2723\Bar<Bug2723\Foo<T4>> but returns Bug2723\BarOfFoo<string>.',
@@ -107,36 +114,42 @@ public function testBug2723(): void
 	public function testBug5706(): void
 	{
 		$this->checkExplicitMixed = false;
+		$this->checkNullables = true;
 		$this->analyse([__DIR__ . '/data/bug-5706.php'], []);
 	}
 
 	public function testBug5844(): void
 	{
 		$this->checkExplicitMixed = false;
+		$this->checkNullables = true;
 		$this->analyse([__DIR__ . '/data/bug-5844.php'], []);
 	}
 
 	public function testBug7218(): void
 	{
 		$this->checkExplicitMixed = true;
+		$this->checkNullables = true;
 		$this->analyse([__DIR__ . '/data/bug-7218.php'], []);
 	}
 
 	public function testBug5751(): void
 	{
 		$this->checkExplicitMixed = true;
+		$this->checkNullables = true;
 		$this->analyse([__DIR__ . '/data/bug-5751.php'], []);
 	}
 
 	public function testBug3931(): void
 	{
 		$this->checkExplicitMixed = true;
+		$this->checkNullables = true;
 		$this->analyse([__DIR__ . '/data/bug-3931.php'], []);
 	}
 
 	public function testBug3801(): void
 	{
 		$this->checkExplicitMixed = true;
+		$this->checkNullables = true;
 		$this->analyse([__DIR__ . '/data/bug-3801.php'], [
 			[
 				'Function Bug3801\do_foo() should return array{bool, null}|array{null, bool} but returns array{false, true}.',
@@ -149,4 +162,23 @@ public function testBug3801(): void
 		]);
 	}
 
+	public function testListWithNullablesChecked(): void
+	{
+		$this->checkExplicitMixed = false;
+		$this->checkNullables = true;
+		$this->analyse([__DIR__ . '/data/return-list-nullables.php'], [
+			[
+				'Function ReturnListNullables\doFoo() should return array<string>|null but returns array<int, string|null>.',
+				16,
+			],
+		]);
+	}
+
+	public function testListWithNullablesUnchecked(): void
+	{
+		$this->checkExplicitMixed = false;
+		$this->checkNullables = false;
+		$this->analyse([__DIR__ . '/data/return-list-nullables.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Functions/data/return-list-nullables.php b/tests/PHPStan/Rules/Functions/data/return-list-nullables.php
new file mode 100644
index 0000000000..ae6762061f
--- /dev/null
+++ b/tests/PHPStan/Rules/Functions/data/return-list-nullables.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace ReturnListNullables;
+
+/**
+ * @param array<string|null> $x
+ * @return array<string>|null
+ */
+function doFoo(array $x): ?array
+{
+	$list = [];
+	foreach ($x as $v) {
+		$list[] = $v;
+	}
+
+	return $list;
+}