diff --git a/examples/clients/postgresql.php b/examples/clients/postgresql.php
index 62a50db..a8572e2 100755
--- a/examples/clients/postgresql.php
+++ b/examples/clients/postgresql.php
@@ -35,6 +35,11 @@
     foreach ($connections as $connection) {
         Coroutine::create(function () use ($connection) {
             $stmt = $connection->prepare('SELECT pg_sleep(3)');
+            if ($stmt === false) {
+                echo 'Failed to prepare the statement.', PHP_EOL;
+                return;
+            }
+
             $stmt->execute(); // The query finishes in 3 seconds.
             $stmt->fetchAll();
             // The result array returned is:
diff --git a/examples/clients/tcp.php b/examples/clients/tcp.php
index dd564a0..6ca90bb 100755
--- a/examples/clients/tcp.php
+++ b/examples/clients/tcp.php
@@ -26,7 +26,7 @@
             $client = new Client(SWOOLE_TCP);
             $client->connect('server', $port);
             $client->send("client side message to port {$port}");
-            echo $client->recv(), PHP_EOL;
+            echo $client->recv(), PHP_EOL; // @phpstan-ignore echo.nonString
             $client->close();
         });
     }
diff --git a/examples/clients/udp.php b/examples/clients/udp.php
index cddfae3..2b053ab 100755
--- a/examples/clients/udp.php
+++ b/examples/clients/udp.php
@@ -21,6 +21,6 @@
     $client = new Client(SWOOLE_SOCK_UDP, SWOOLE_SOCK_SYNC);
     $client->connect('server', 9506);
     $client->send('Hello Swoole!');
-    echo $client->recv(), PHP_EOL;
+    echo $client->recv(), PHP_EOL; // @phpstan-ignore echo.nonString
     $client->close();
 });
diff --git a/examples/clients/websocket.php b/examples/clients/websocket.php
index 220b8e4..9e6f5ec 100755
--- a/examples/clients/websocket.php
+++ b/examples/clients/websocket.php
@@ -20,7 +20,7 @@
         $client = new Client('server', 9504);
         $client->upgrade('/');
         $client->push('Swoole');
-        echo $client->recv()->data, PHP_EOL;
+        echo $client->recv()->data, PHP_EOL; // @phpstan-ignore property.nonObject
         $client->close();
     });
 });
diff --git a/examples/csp/barrier.php b/examples/csp/barrier.php
index 4de80cd..d26a1d9 100755
--- a/examples/csp/barrier.php
+++ b/examples/csp/barrier.php
@@ -27,14 +27,14 @@
 run(function () {
     $barrier = Barrier::make();
 
-    go(function () use ($barrier) {
+    go(function () use ($barrier) { // @phpstan-ignore closure.unusedUse
         sleep(1);
     });
 
-    go(function () use ($barrier) {
+    go(function () use ($barrier) { // @phpstan-ignore closure.unusedUse
         sleep(2);
     });
-    go(function () use ($barrier) {
+    go(function () use ($barrier) { // @phpstan-ignore closure.unusedUse
         sleep(3);
     });
 
diff --git a/examples/csp/context.php b/examples/csp/context.php
index 40b3ff5..4e09163 100755
--- a/examples/csp/context.php
+++ b/examples/csp/context.php
@@ -52,16 +52,18 @@ public function __destruct()
     };
 
     // The Context object of a coroutine works the same as an \ArrayObject object.
-    Coroutine::getContext()['co1_obj1']                  = new $class('co1_obj1');
-    Coroutine::getContext(Coroutine::getCid())->co1_obj2 = new $class('co1_obj2'); // Coroutine::getCid() returns 1.
+    Coroutine::getContext()['co1_obj1']   = new $class('co1_obj1'); // @phpstan-ignore offsetAccess.nonOffsetAccessible
+    $cid                                  = Coroutine::getCid();    // Coroutine::getCid() returns 1.
+    Coroutine::getContext($cid)->co1_obj2 = new $class('co1_obj2'); // @phpstan-ignore property.nonObject
 
     Coroutine::create(function () use ($class) {
         // The Context object of a coroutine works the same as an \ArrayObject object.
-        Coroutine::getContext()['co2_obj1']                  = new $class('co2_obj1');
-        Coroutine::getContext(Coroutine::getCid())->co2_obj2 = new $class('co2_obj2'); // Coroutine::getCid() returns 2.
+        Coroutine::getContext()['co2_obj1']   = new $class('co2_obj1'); // @phpstan-ignore offsetAccess.nonOffsetAccessible
+        $cid                                  = Coroutine::getCid();    // Coroutine::getCid() returns 2.
+        Coroutine::getContext($cid)->co2_obj2 = new $class('co2_obj2'); // @phpstan-ignore property.nonObject
 
-        echo 'Name of the 1st object in the Context object of coroutine #1: ', Coroutine::getContext(1)['co1_obj1']->name, PHP_EOL;
-        echo 'Name of the 2nd object in the Context object of coroutine #2: ', Coroutine::getContext(2)->co2_obj2->name, PHP_EOL;
+        echo 'Name of the 1st object in the Context object of coroutine #1: ', Coroutine::getContext(1)['co1_obj1']->name, PHP_EOL; // @phpstan-ignore-line
+        echo 'Name of the 2nd object in the Context object of coroutine #2: ', Coroutine::getContext(2)->co2_obj2->name, PHP_EOL; // @phpstan-ignore property.nonObject
 
         echo PHP_EOL, 'Coroutine #2 is exiting. The context object of it will be destroyed.', PHP_EOL;
     });
diff --git a/examples/csp/coroutines/benchmark.php b/examples/csp/coroutines/benchmark.php
index 0e7431d..9f5483e 100755
--- a/examples/csp/coroutines/benchmark.php
+++ b/examples/csp/coroutines/benchmark.php
@@ -63,7 +63,7 @@
         if (($i % 100_000) === 0) {
             printf(
                 '%07d active coroutines; total time: %f seconds; memory usage: %d.' . PHP_EOL,
-                count(Coroutine::listCoroutines()),
+                count(Coroutine::listCoroutines()), // @phpstan-ignore argument.type
                 microtime(true) - $startTime,
                 memory_get_usage()
             );
diff --git a/examples/csp/coroutines/exit.php b/examples/csp/coroutines/exit.php
index 7907dc0..56f60d7 100755
--- a/examples/csp/coroutines/exit.php
+++ b/examples/csp/coroutines/exit.php
@@ -19,7 +19,7 @@
 run(function () {
     try {
         exit(911);
-    } catch (Swoole\ExitException $e) {
+    } catch (Swoole\ExitException $e) { // @phpstan-ignore catch.neverThrown
         echo <<<EOT
         Calling exit() inside a coroutine throws out a \\Swoole\\ExitException exception instead of terminating code execution
         directly.
diff --git a/examples/csp/coroutines/for.php b/examples/csp/coroutines/for.php
index 03a1656..cf8224f 100755
--- a/examples/csp/coroutines/for.php
+++ b/examples/csp/coroutines/for.php
@@ -27,5 +27,5 @@
     }
 
     // Note that there are 2,001 coroutines created, including the main coroutine created by function call run().
-    echo count(Coroutine::listCoroutines()), ' active coroutines when reaching the end of the PHP script.', PHP_EOL;
+    echo count(Coroutine::listCoroutines()), ' active coroutines when reaching the end of the PHP script.', PHP_EOL; // @phpstan-ignore argument.type
 });
diff --git a/examples/csp/deadlocks/coroutine-yielded-3.php b/examples/csp/deadlocks/coroutine-yielded-3.php
index b0f5482..3d4fc1f 100755
--- a/examples/csp/deadlocks/coroutine-yielded-3.php
+++ b/examples/csp/deadlocks/coroutine-yielded-3.php
@@ -21,7 +21,7 @@
 Coroutine::set(
     [
         Constant::OPTION_EXIT_CONDITION => function () {
-            return Coroutine::stats()['coroutine_num'] === 0;
+            return Coroutine::stats()['coroutine_num'] === 0; // @phpstan-ignore offsetAccess.nonOffsetAccessible
         },
     ]
 );
diff --git a/examples/csp/deadlocks/file-locking.php b/examples/csp/deadlocks/file-locking.php
index e4a7421..68724d0 100755
--- a/examples/csp/deadlocks/file-locking.php
+++ b/examples/csp/deadlocks/file-locking.php
@@ -27,11 +27,19 @@
     $filename = sys_get_temp_dir() . '/swoole-file-locking-' . uniqid() . '.tmp';
 
     $fp1 = fopen($filename, 'w');
+    if ($fp1 === false) {
+        throw new RuntimeException('Failed to open file.');
+    }
+
     flock($fp1, LOCK_EX); // To acquire an exclusive lock (writer).
 
     echo '2', PHP_EOL; // This will be printed out.
 
     $fp2 = fopen($filename, 'w');
+    if ($fp2 === false) {
+        throw new RuntimeException('Failed to open file.');
+    }
+
     flock($fp2, LOCK_EX); // Trying to acquire an exclusive lock (writer) again on the same file.
 
     // Whatever code you put here (within the coroutine) will never be executed.
diff --git a/examples/csp/scheduling/non-preemptive.php b/examples/csp/scheduling/non-preemptive.php
index c864378..1277338 100755
--- a/examples/csp/scheduling/non-preemptive.php
+++ b/examples/csp/scheduling/non-preemptive.php
@@ -18,7 +18,7 @@
     function () {
         go(function () {
             $i = 0;
-            while (true) {
+            while (true) { // @phpstan-ignore while.alwaysTrue
                 echo $i++, PHP_EOL;
             }
         });
diff --git a/examples/csp/scheduling/preemptive.php b/examples/csp/scheduling/preemptive.php
index 17afc04..c4913e8 100755
--- a/examples/csp/scheduling/preemptive.php
+++ b/examples/csp/scheduling/preemptive.php
@@ -20,7 +20,7 @@
     function () {
         go(function () {
             $i = 0;
-            while (true) {
+            while (true) { // @phpstan-ignore while.alwaysTrue
                 echo $i++, PHP_EOL;
             }
         });
diff --git a/examples/hooks/mysqli.php b/examples/hooks/mysqli.php
index 1887716..42246e5 100755
--- a/examples/hooks/mysqli.php
+++ b/examples/hooks/mysqli.php
@@ -31,6 +31,11 @@
         go(function () {
             $mysqli = new mysqli('mysql', 'username', 'password', 'test');
             $stmt   = $mysqli->prepare('SELECT SLEEP(3)');
+            if ($stmt === false) {
+                echo 'Failed to prepare the statement.', PHP_EOL;
+                return;
+            }
+
             $stmt->execute();
             $stmt->close();
             $mysqli->close();
diff --git a/examples/io/blocking-vs-non-blocking.php b/examples/io/blocking-vs-non-blocking.php
index 4febd17..3feaf5a 100755
--- a/examples/io/blocking-vs-non-blocking.php
+++ b/examples/io/blocking-vs-non-blocking.php
@@ -23,7 +23,7 @@
 
 use function Swoole\Coroutine\go;
 
-function blocking()
+function blocking(): string
 {
     go(function () {
         echo '1';
@@ -33,7 +33,7 @@ function blocking()
     return '3';
 }
 
-function nonBlocking()
+function nonBlocking(): string
 {
     go(function () {
         echo '4';
diff --git a/examples/pool/process-pool/client.php b/examples/pool/process-pool/client.php
index c794042..1810381 100755
--- a/examples/pool/process-pool/client.php
+++ b/examples/pool/process-pool/client.php
@@ -36,7 +36,7 @@
             for ($i = 0; $i < 3; $i++) {
                 // On the server side, you will see output messages like the following:
                 // Process #0 received message "s:35:"Message #0 via class Swoole\MsgQueue!";". (MSGQUEUE)
-                $mq->push(sprintf('Message #%d via class %s!', $i, MsgQueue::class)); // @phpstan-ignore class.notFound
+                $mq->push(sprintf('Message #%d via class %s!', $i, MsgQueue::class)); // @phpstan-ignore class.notFound,class.notFound
             }
         });
     }
@@ -45,6 +45,10 @@
     if (function_exists('msg_get_queue')) {
         go(function () {
             $mq = msg_get_queue(0x7000001);
+            if ($mq === false) {
+                echo 'Failed to get message queue.', PHP_EOL;
+                return;
+            }
             for ($i = 0; $i < 3; $i++) {
                 // On the server side, you will see output messages like the following:
                 // Process #0 received message "s:35:"Message #0 via function msg_send()!";". (MSGQUEUE)
@@ -61,7 +65,7 @@
         $requestMessage = 'TCP socket';
         $client->send(pack('N', strlen($requestMessage)) . $requestMessage);
         $responseMessage = $client->recv();
-        $responseMessage = substr($responseMessage, 4, unpack('N', substr($responseMessage, 0, 4))[1]);
+        $responseMessage = substr($responseMessage, 4, unpack('N', substr($responseMessage, 0, 4))[1]); // @phpstan-ignore-line
         echo $responseMessage, PHP_EOL;
         $client->close();
     });
@@ -75,7 +79,7 @@
         $requestMessage = 'Unix socket';
         $client->send(pack('N', strlen($requestMessage)) . $requestMessage);
         $responseMessage = $client->recv();
-        $responseMessage = substr($responseMessage, 4, unpack('N', substr($responseMessage, 0, 4))[1]);
+        $responseMessage = substr($responseMessage, 4, unpack('N', substr($responseMessage, 0, 4))[1]); // @phpstan-ignore-line
         echo $responseMessage, PHP_EOL;
         $client->close();
     });
diff --git a/examples/pool/process-pool/pool-standalone.php b/examples/pool/process-pool/pool-standalone.php
index f1367d3..f109e46 100755
--- a/examples/pool/process-pool/pool-standalone.php
+++ b/examples/pool/process-pool/pool-standalone.php
@@ -22,11 +22,11 @@
 
 $pool->on('workerStart', function (Pool $pool, int $workerId) use ($counter) {
     # For standalone process pool, business logic should be implemented inside this "workerStart" callback.
-    echo "Process #{$workerId} (process ID in the OS: {$pool->getProcess()->pid}) started.", PHP_EOL;
+    echo "Process #{$workerId} (process ID in the OS: {$pool->getProcess()->pid}) started.", PHP_EOL; // @phpstan-ignore property.nonObject
     $counter->add(1);
 });
 $pool->on('workerStop', function (Pool $pool, int $workerId) use ($counter) {
-    echo "Process #{$workerId} (process ID in the OS: {$pool->getProcess()->pid}) stopped.", PHP_EOL;
+    echo "Process #{$workerId} (process ID in the OS: {$pool->getProcess()->pid}) stopped.", PHP_EOL; // @phpstan-ignore property.nonObject
     if ($counter->get() >= 3) {
         $pool->shutdown();
     }
diff --git a/examples/servers/http1-integrated.php b/examples/servers/http1-integrated.php
index 1f02572..7cec1f0 100755
--- a/examples/servers/http1-integrated.php
+++ b/examples/servers/http1-integrated.php
@@ -53,7 +53,7 @@ function (Server $server, int $workerId) {
         if ($workerId === 0) {
             // Here we start the second cron job that runs every 63 seconds.
             Coroutine::create(function () {
-                while (true) {
+                while (true) { // @phpstan-ignore while.alwaysTrue
                     Coroutine::sleep(63);
                     echo '[HTTP1-ADVANCED]: This message is printed out every 63 seconds. (', date('H:i:s'), ')', PHP_EOL;
                 }
diff --git a/examples/servers/redis.php b/examples/servers/redis.php
index 856afad..0593789 100755
--- a/examples/servers/redis.php
+++ b/examples/servers/redis.php
@@ -22,8 +22,10 @@
 
 use Swoole\Redis\Server;
 
-$server       = new Server('0.0.0.0', 6379);
-$server->data = []; // We use an array as the data storage for the Redis server.
+$server = new Server('0.0.0.0', 6379);
+
+// We use an array as the data storage for the Redis server.
+$server->data = []; // @phpstan-ignore property.notFound
 
 $server->setHandler('SET', function (int $fd, array $data) use ($server) {
     $server->data[$data[0]] = $data[1];
diff --git a/examples/servers/server-events.php b/examples/servers/server-events.php
index 9737ca8..79d4c9a 100755
--- a/examples/servers/server-events.php
+++ b/examples/servers/server-events.php
@@ -42,7 +42,7 @@
 use Swoole\Http\Server;
 use Swoole\Timer;
 
-function printMessage(string $message, bool $newLine = false)
+function printMessage(string $message, bool $newLine = false): void
 {
     echo ($newLine ? PHP_EOL : ''), 'INFO (', date('H:i:s'), "): {$message}", PHP_EOL;
 }
diff --git a/examples/servers/websocket-integrated.php b/examples/servers/websocket-integrated.php
index 1debd22..01d64f9 100755
--- a/examples/servers/websocket-integrated.php
+++ b/examples/servers/websocket-integrated.php
@@ -44,7 +44,7 @@ function () {
 
 $process = new Process(
     function () {
-        while (true) {
+        while (true) { // @phpstan-ignore while.alwaysTrue
             sleep(31);
             echo 'Cron executed (in file ',  __FILE__, ').', PHP_EOL; // To simulate cron executions.
         }
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 3de2006..cb92717 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -1,4 +1,4 @@
 parameters:
-  level: 0
+  level: 9
   paths:
     - ./examples