diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index 7ac09d1e92..589fd947d2 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -208,7 +208,7 @@ public function __construct(
 		private ScopeContext $context,
 		private PhpVersion $phpVersion,
 		private bool $declareStrictTypes = false,
-		private FunctionReflection|ExtendedMethodReflection|null $function = null,
+		private PhpFunctionFromParserNodeReflection|null $function = null,
 		?string $namespace = null,
 		private array $expressionTypes = [],
 		private array $nativeExpressionTypes = [],
@@ -310,9 +310,8 @@ public function getTraitReflection(): ?ClassReflection
 
 	/**
 	 * @api
-	 * @return FunctionReflection|ExtendedMethodReflection|null
 	 */
-	public function getFunction()
+	public function getFunction(): ?PhpFunctionFromParserNodeReflection
 	{
 		return $this->function;
 	}
diff --git a/src/Analyser/NodeScopeResolver.php b/src/Analyser/NodeScopeResolver.php
index 6871211346..c9ae804546 100644
--- a/src/Analyser/NodeScopeResolver.php
+++ b/src/Analyser/NodeScopeResolver.php
@@ -728,7 +728,7 @@ private function processStmtNode(
 				$classReflection = $scope->getClassReflection();
 
 				$methodReflection = $methodScope->getFunction();
-				if (!$methodReflection instanceof ExtendedMethodReflection) {
+				if (!$methodReflection instanceof PhpMethodFromParserNodeReflection) {
 					throw new ShouldNotHappenException();
 				}
 
diff --git a/src/Analyser/Scope.php b/src/Analyser/Scope.php
index 53ceaa3443..0c1682209d 100644
--- a/src/Analyser/Scope.php
+++ b/src/Analyser/Scope.php
@@ -16,6 +16,7 @@
 use PHPStan\Reflection\NamespaceAnswerer;
 use PHPStan\Reflection\ParameterReflection;
 use PHPStan\Reflection\ParametersAcceptor;
+use PHPStan\Reflection\Php\PhpFunctionFromParserNodeReflection;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeWithClassName;
@@ -49,10 +50,7 @@ public function isInTrait(): bool;
 
 	public function getTraitReflection(): ?ClassReflection;
 
-	/**
-	 * @return FunctionReflection|ExtendedMethodReflection|null
-	 */
-	public function getFunction();
+	public function getFunction(): ?PhpFunctionFromParserNodeReflection;
 
 	public function getFunctionName(): ?string;
 
diff --git a/src/Node/FunctionReturnStatementsNode.php b/src/Node/FunctionReturnStatementsNode.php
index 0b065f8a25..4ab53d25c3 100644
--- a/src/Node/FunctionReturnStatementsNode.php
+++ b/src/Node/FunctionReturnStatementsNode.php
@@ -9,7 +9,7 @@
 use PhpParser\NodeAbstract;
 use PHPStan\Analyser\ImpurePoint;
 use PHPStan\Analyser\StatementResult;
-use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Reflection\Php\PhpFunctionFromParserNodeReflection;
 use function count;
 
 /**
@@ -32,7 +32,7 @@ public function __construct(
 		private StatementResult $statementResult,
 		private array $executionEnds,
 		private array $impurePoints,
-		private FunctionReflection $functionReflection,
+		private PhpFunctionFromParserNodeReflection $functionReflection,
 	)
 	{
 		parent::__construct($function->getAttributes());
@@ -91,7 +91,7 @@ public function getSubNodeNames(): array
 		return [];
 	}
 
-	public function getFunctionReflection(): FunctionReflection
+	public function getFunctionReflection(): PhpFunctionFromParserNodeReflection
 	{
 		return $this->functionReflection;
 	}
diff --git a/src/Node/MethodReturnStatementsNode.php b/src/Node/MethodReturnStatementsNode.php
index 0103f58059..96218713d3 100644
--- a/src/Node/MethodReturnStatementsNode.php
+++ b/src/Node/MethodReturnStatementsNode.php
@@ -10,7 +10,7 @@
 use PHPStan\Analyser\ImpurePoint;
 use PHPStan\Analyser\StatementResult;
 use PHPStan\Reflection\ClassReflection;
-use PHPStan\Reflection\ExtendedMethodReflection;
+use PHPStan\Reflection\Php\PhpMethodFromParserNodeReflection;
 use function count;
 
 /**
@@ -36,7 +36,7 @@ public function __construct(
 		private array $executionEnds,
 		private array $impurePoints,
 		private ClassReflection $classReflection,
-		private ExtendedMethodReflection $methodReflection,
+		private PhpMethodFromParserNodeReflection $methodReflection,
 	)
 	{
 		parent::__construct($method->getAttributes());
@@ -88,7 +88,7 @@ public function getClassReflection(): ClassReflection
 		return $this->classReflection;
 	}
 
-	public function getMethodReflection(): ExtendedMethodReflection
+	public function getMethodReflection(): PhpMethodFromParserNodeReflection
 	{
 		return $this->methodReflection;
 	}
diff --git a/src/Rules/Api/ApiInstanceofRule.php b/src/Rules/Api/ApiInstanceofRule.php
index 7882c3473e..db7c28afff 100644
--- a/src/Rules/Api/ApiInstanceofRule.php
+++ b/src/Rules/Api/ApiInstanceofRule.php
@@ -84,6 +84,9 @@ private function processCoveredClass(Node\Expr\Instanceof_ $node, Scope $scope,
 		if ($classReflection->getName() === Type::class || $classReflection->isSubclassOf(Type::class)) {
 			return [];
 		}
+		if ($classReflection->isInterface()) {
+			return [];
+		}
 
 		$instanceofType = $scope->getType($node);
 		if ($instanceofType->isTrue()->or($instanceofType->isFalse())->yes()) {
diff --git a/src/Rules/Functions/ReturnTypeRule.php b/src/Rules/Functions/ReturnTypeRule.php
index 4a02e64989..8d4714f423 100644
--- a/src/Rules/Functions/ReturnTypeRule.php
+++ b/src/Rules/Functions/ReturnTypeRule.php
@@ -5,9 +5,8 @@
 use PhpParser\Node;
 use PhpParser\Node\Stmt\Return_;
 use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\MethodReflection;
 use PHPStan\Reflection\ParametersAcceptorSelector;
-use PHPStan\Reflection\Php\PhpFunctionFromParserNodeReflection;
-use PHPStan\Reflection\Php\PhpMethodFromParserNodeReflection;
 use PHPStan\Rules\FunctionReturnTypeCheck;
 use PHPStan\Rules\Rule;
 use function sprintf;
@@ -40,10 +39,7 @@ public function processNode(Node $node, Scope $scope): array
 		}
 
 		$function = $scope->getFunction();
-		if (
-			!($function instanceof PhpFunctionFromParserNodeReflection)
-			|| $function instanceof PhpMethodFromParserNodeReflection
-		) {
+		if ($function instanceof MethodReflection) {
 			return [];
 		}