diff --git a/src/Collector/MethodCallCollector.php b/src/Collector/MethodCallCollector.php
index 2d90e00..66e31d7 100644
--- a/src/Collector/MethodCallCollector.php
+++ b/src/Collector/MethodCallCollector.php
@@ -13,6 +13,7 @@
 use PhpParser\Node\Name;
 use PHPStan\Analyser\Scope;
 use PHPStan\Collectors\Collector;
+use PHPStan\Node\ClassMethodsNode;
 use PHPStan\Node\MethodCallableNode;
 use PHPStan\Node\StaticMethodCallableNode;
 use PHPStan\Reflection\ClassReflection;
@@ -28,6 +29,11 @@ class MethodCallCollector implements Collector
 
     private ReflectionProvider $reflectionProvider;
 
+    /**
+     * @var list<string>
+     */
+    private array $callsBuffer = [];
+
     public function __construct(ReflectionProvider $reflectionProvider)
     {
         $this->reflectionProvider = $reflectionProvider;
@@ -47,23 +53,29 @@ public function processNode(
     ): ?array
     {
         if ($node instanceof MethodCallableNode) { // @phpstan-ignore-line ignore BC promise
-            return $this->registerMethodCall($node->getOriginalNode(), $scope);
+            $this->registerMethodCall($node->getOriginalNode(), $scope);
         }
 
         if ($node instanceof StaticMethodCallableNode) { // @phpstan-ignore-line ignore BC promise
-            return $this->registerStaticCall($node->getOriginalNode(), $scope);
+            $this->registerStaticCall($node->getOriginalNode(), $scope);
         }
 
         if ($node instanceof MethodCall || $node instanceof NullsafeMethodCall) {
-            return $this->registerMethodCall($node, $scope);
+            $this->registerMethodCall($node, $scope);
         }
 
         if ($node instanceof StaticCall) {
-            return $this->registerStaticCall($node, $scope);
+            $this->registerStaticCall($node, $scope);
         }
 
         if ($node instanceof FuncCall) {
-            return $this->registerFuncCall($node, $scope);
+            $this->registerFuncCall($node, $scope);
+        }
+
+        if (!$scope->isInClass() || $node instanceof ClassMethodsNode) { // @phpstan-ignore-line ignore BC promise
+            $data = $this->callsBuffer;
+            $this->callsBuffer = [];
+            return $data === [] ? null : $data; // collect data once per class to save memory & resultCache size
         }
 
         return null;
@@ -71,42 +83,34 @@ public function processNode(
 
     /**
      * @param NullsafeMethodCall|MethodCall $methodCall
-     * @return list<string>|null
      */
     private function registerMethodCall(
         CallLike $methodCall,
         Scope $scope
-    ): ?array
+    ): void
     {
         $methodName = $this->getMethodName($methodCall);
         $callerType = $scope->getType($methodCall->var);
 
         if ($methodName === null) {
-            return null;
+            return;
         }
 
-        $result = [];
-
         foreach ($this->getReflectionsWithMethod($callerType, $methodName) as $classWithMethod) {
             $className = $classWithMethod->getMethod($methodName, $scope)->getDeclaringClass()->getName();
-            $result[] = DeadCodeHelper::composeMethodKey($className, $methodName);
+            $this->callsBuffer[] = DeadCodeHelper::composeMethodKey($className, $methodName);
         }
-
-        return $result !== [] ? $result : null;
     }
 
-    /**
-     * @return list<string>|null
-     */
     private function registerStaticCall(
         StaticCall $staticCall,
         Scope $scope
-    ): ?array
+    ): void
     {
         $methodName = $this->getMethodName($staticCall);
 
         if ($methodName === null) {
-            return null;
+            return;
         }
 
         if ($staticCall->class instanceof Expr) {
@@ -124,26 +128,19 @@ private function registerStaticCall(
             }
         }
 
-        $result = [];
-
         foreach ($classReflections as $classWithMethod) {
             $className = $classWithMethod->getMethod($methodName, $scope)->getDeclaringClass()->getName();
-            $result[] = DeadCodeHelper::composeMethodKey($className, $methodName);
+            $this->callsBuffer[] = DeadCodeHelper::composeMethodKey($className, $methodName);
         }
-
-        return $result !== [] ? $result : null;
     }
 
-    /**
-     * @return list<string>|null
-     */
     private function registerFuncCall(
         FuncCall $functionCall,
         Scope $scope
-    ): ?array
+    ): void
     {
         if (!$functionCall->name instanceof Name || $functionCall->name->toString() !== 'array_map') { // we should support all native fns
-            return null;
+            return;
         }
 
         $callableType = $scope->getType($functionCall->getArgs()[0]->value);
@@ -152,24 +149,16 @@ private function registerFuncCall(
             foreach ($callableType->getConstantArrays() as $constantArray) {
                 $callableTypeAndNames = $constantArray->findTypeAndMethodNames();
 
-                $result = [];
-
                 foreach ($callableTypeAndNames as $typeAndName) {
                     $methodName = $typeAndName->getMethod();
 
                     foreach ($this->getReflectionsWithMethod($typeAndName->getType(), $methodName) as $classWithMethod) {
                         $className = $classWithMethod->getMethod($methodName, $scope)->getDeclaringClass()->getName();
-                        $result[] = DeadCodeHelper::composeMethodKey($className, $methodName);
+                        $this->callsBuffer[] = DeadCodeHelper::composeMethodKey($className, $methodName);
                     }
                 }
-
-                if ($result !== []) {
-                    return $result;
-                }
             }
         }
-
-        return null;
     }
 
     /**