diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 43c9cb3f..e6939582 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -35,6 +35,7 @@ jobs:
     name: PHPStan (PHP ${{ matrix.php }})
     runs-on: ubuntu-22.04
     strategy:
+      fail-fast: false
       matrix:
         php:
           - 8.2
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 895c8410..0e153421 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -4,3 +4,4 @@ parameters:
     paths:
         - src/
         - tests/
+        - types/
diff --git a/src/Deferred.php b/src/Deferred.php
index 82f66dad..28ab18bf 100644
--- a/src/Deferred.php
+++ b/src/Deferred.php
@@ -2,9 +2,14 @@
 
 namespace React\Promise;
 
+/**
+ * @template-covariant  T
+ */
 final class Deferred
 {
-    /** @var Promise */
+    /**
+     * @var PromiseInterface<T>
+     */
     private $promise;
 
     /** @var callable */
@@ -21,6 +26,9 @@ public function __construct(callable $canceller = null)
         }, $canceller);
     }
 
+    /**
+     * @return PromiseInterface<T>
+     */
     public function promise(): PromiseInterface
     {
         return $this->promise;
diff --git a/src/Internal/FulfilledPromise.php b/src/Internal/FulfilledPromise.php
index 0712f763..7806b46a 100644
--- a/src/Internal/FulfilledPromise.php
+++ b/src/Internal/FulfilledPromise.php
@@ -7,14 +7,17 @@
 
 /**
  * @internal
+ *
+ * @template-implements PromiseInterface<T>
+ * @template-covariant T
  */
 final class FulfilledPromise implements PromiseInterface
 {
-    /** @var mixed */
+    /** @var T */
     private $value;
 
     /**
-     * @param mixed $value
+     * @param T $value
      * @throws \InvalidArgumentException
      */
     public function __construct($value = null)
@@ -26,6 +29,9 @@ public function __construct($value = null)
         $this->value = $value;
     }
 
+    /**
+     * @inheritdoc
+     */
     public function then(callable $onFulfilled = null, callable $onRejected = null): PromiseInterface
     {
         if (null === $onFulfilled) {
@@ -39,11 +45,17 @@ public function then(callable $onFulfilled = null, callable $onRejected = null):
         }
     }
 
+    /**
+     * @inheritdoc
+     */
     public function catch(callable $onRejected): PromiseInterface
     {
         return $this;
     }
 
+    /**
+     * @inheritdoc
+     */
     public function finally(callable $onFulfilledOrRejected): PromiseInterface
     {
         return $this->then(function ($value) use ($onFulfilledOrRejected): PromiseInterface {
@@ -60,6 +72,7 @@ public function cancel(): void
     /**
      * @deprecated 3.0.0 Use `catch()` instead
      * @see self::catch()
+     * @inheritdoc
      */
     public function otherwise(callable $onRejected): PromiseInterface
     {
@@ -69,6 +82,7 @@ public function otherwise(callable $onRejected): PromiseInterface
     /**
      * @deprecated 3.0.0 Use `finally()` instead
      * @see self::finally()
+     * @inheritdoc
      */
     public function always(callable $onFulfilledOrRejected): PromiseInterface
     {
diff --git a/src/Internal/RejectedPromise.php b/src/Internal/RejectedPromise.php
index cbd8ef53..7802aa4e 100644
--- a/src/Internal/RejectedPromise.php
+++ b/src/Internal/RejectedPromise.php
@@ -8,6 +8,9 @@
 
 /**
  * @internal
+ *
+ * @template-implements PromiseInterface<T>
+ * @template-covariant T
  */
 final class RejectedPromise implements PromiseInterface
 {
@@ -22,6 +25,9 @@ public function __construct(\Throwable $reason)
         $this->reason = $reason;
     }
 
+    /**
+     * @inheritdoc
+     */
     public function then(callable $onFulfilled = null, callable $onRejected = null): PromiseInterface
     {
         if (null === $onRejected) {
@@ -35,6 +41,9 @@ public function then(callable $onFulfilled = null, callable $onRejected = null):
         }
     }
 
+    /**
+     * @inheritdoc
+     */
     public function catch(callable $onRejected): PromiseInterface
     {
         if (!_checkTypehint($onRejected, $this->reason)) {
@@ -44,6 +53,9 @@ public function catch(callable $onRejected): PromiseInterface
         return $this->then(null, $onRejected);
     }
 
+    /**
+     * @inheritdoc
+     */
     public function finally(callable $onFulfilledOrRejected): PromiseInterface
     {
         return $this->then(null, function (\Throwable $reason) use ($onFulfilledOrRejected): PromiseInterface {
@@ -60,6 +72,7 @@ public function cancel(): void
     /**
      * @deprecated 3.0.0 Use `catch()` instead
      * @see self::catch()
+     * @inheritdoc
      */
     public function otherwise(callable $onRejected): PromiseInterface
     {
@@ -69,6 +82,7 @@ public function otherwise(callable $onRejected): PromiseInterface
     /**
      * @deprecated 3.0.0 Use `always()` instead
      * @see self::always()
+     * @inheritdoc
      */
     public function always(callable $onFulfilledOrRejected): PromiseInterface
     {
diff --git a/src/Promise.php b/src/Promise.php
index a2d72b6d..e25a5ec4 100644
--- a/src/Promise.php
+++ b/src/Promise.php
@@ -3,13 +3,18 @@
 namespace React\Promise;
 
 use React\Promise\Internal\RejectedPromise;
+use Throwable;
 
+/**
+ * @template-implements PromiseInterface<T>
+ * @template-covariant T
+ */
 final class Promise implements PromiseInterface
 {
     /** @var ?callable */
     private $canceller;
 
-    /** @var ?PromiseInterface */
+    /** @var PromiseInterface<T> */
     private $result;
 
     /** @var callable[] */
@@ -30,6 +35,9 @@ public function __construct(callable $resolver, callable $canceller = null)
         $this->call($cb);
     }
 
+    /**
+     * @inheritdoc
+     */
     public function then(callable $onFulfilled = null, callable $onRejected = null): PromiseInterface
     {
         if (null !== $this->result) {
@@ -63,6 +71,9 @@ static function () use (&$parent) {
         );
     }
 
+    /**
+     * @inheritdoc
+     */
     public function catch(callable $onRejected): PromiseInterface
     {
         return $this->then(null, static function ($reason) use ($onRejected) {
@@ -74,14 +85,17 @@ public function catch(callable $onRejected): PromiseInterface
         });
     }
 
+    /**
+     * @inheritdoc
+     */
     public function finally(callable $onFulfilledOrRejected): PromiseInterface
     {
         return $this->then(static function ($value) use ($onFulfilledOrRejected) {
-            return resolve($onFulfilledOrRejected())->then(function () use ($value) {
+            return resolve($onFulfilledOrRejected())->then(function ($_) use ($value) {
                 return $value;
             });
         }, static function ($reason) use ($onFulfilledOrRejected) {
-            return resolve($onFulfilledOrRejected())->then(function () use ($reason) {
+            return resolve($onFulfilledOrRejected())->then(function ($_) use ($reason) {
                 return new RejectedPromise($reason);
             });
         });
@@ -125,6 +139,7 @@ public function cancel(): void
     /**
      * @deprecated 3.0.0 Use `catch()` instead
      * @see self::catch()
+     * @inheritdoc
      */
     public function otherwise(callable $onRejected): PromiseInterface
     {
@@ -134,6 +149,7 @@ public function otherwise(callable $onRejected): PromiseInterface
     /**
      * @deprecated 3.0.0 Use `finally()` instead
      * @see self::finally()
+     * @inheritdoc
      */
     public function always(callable $onFulfilledOrRejected): PromiseInterface
     {
@@ -157,7 +173,7 @@ private function resolver(callable $onFulfilled = null, callable $onRejected = n
         };
     }
 
-    private function reject(\Throwable $reason): void
+    private function reject(Throwable $reason): void
     {
         if (null !== $this->result) {
             return;
@@ -166,6 +182,9 @@ private function reject(\Throwable $reason): void
         $this->settle(reject($reason));
     }
 
+    /**
+     * @param PromiseInterface<T>|PromiseInterface<null> $result
+     */
     private function settle(PromiseInterface $result): void
     {
         $result = $this->unwrap($result);
@@ -193,13 +212,17 @@ private function settle(PromiseInterface $result): void
         }
     }
 
+    /**
+     * @param PromiseInterface<T>|PromiseInterface<null> $promise
+     * @return PromiseInterface<T>
+     */
     private function unwrap(PromiseInterface $promise): PromiseInterface
     {
         while ($promise instanceof self && null !== $promise->result) {
             $promise = $promise->result;
         }
 
-        return $promise;
+        return $promise; /** @phpstan-ignore-line */
     }
 
     private function call(callable $cb): void
@@ -245,7 +268,7 @@ static function ($value) use (&$target) {
                             $target = null;
                         }
                     },
-                    static function (\Throwable $reason) use (&$target) {
+                    static function (Throwable $reason) use (&$target) {
                         if ($target !== null) {
                             $target->reject($reason);
                             $target = null;
@@ -253,7 +276,7 @@ static function (\Throwable $reason) use (&$target) {
                     }
                 );
             }
-        } catch (\Throwable $e) {
+        } catch (Throwable $e) {
             $target = null;
             $this->reject($e);
         }
diff --git a/src/PromiseInterface.php b/src/PromiseInterface.php
index 47117072..297f1f97 100644
--- a/src/PromiseInterface.php
+++ b/src/PromiseInterface.php
@@ -2,6 +2,9 @@
 
 namespace React\Promise;
 
+/**
+ * @template-covariant T
+ */
 interface PromiseInterface
 {
     /**
@@ -28,9 +31,9 @@ interface PromiseInterface
      *  2. `$onFulfilled` and `$onRejected` will never be called more
      *      than once.
      *
-     * @param callable|null $onFulfilled
-     * @param callable|null $onRejected
-     * @return PromiseInterface
+     * @template TFulfilled as PromiseInterface<T>|T
+     * @param (callable(T): TFulfilled)|null $onFulfilled
+     * @return PromiseInterface<T>
      */
     public function then(?callable $onFulfilled = null, ?callable $onRejected = null): PromiseInterface;
 
@@ -44,8 +47,7 @@ public function then(?callable $onFulfilled = null, ?callable $onRejected = null
      * Additionally, you can type hint the `$reason` argument of `$onRejected` to catch
      * only specific errors.
      *
-     * @param callable $onRejected
-     * @return PromiseInterface
+     * @return PromiseInterface<T>
      */
     public function catch(callable $onRejected): PromiseInterface;
 
@@ -91,8 +93,9 @@ public function catch(callable $onRejected): PromiseInterface;
      *     ->finally('cleanup');
      * ```
      *
-     * @param callable $onFulfilledOrRejected
-     * @return PromiseInterface
+     * @template TReturn of PromiseInterface<T>|T
+     * @param callable(T=): TReturn $onFulfilledOrRejected
+     * @return PromiseInterface<T>
      */
     public function finally(callable $onFulfilledOrRejected): PromiseInterface;
 
@@ -118,7 +121,7 @@ public function cancel(): void;
      * ```
      *
      * @param callable $onRejected
-     * @return PromiseInterface
+     * @return PromiseInterface<T>
      * @deprecated 3.0.0 Use catch() instead
      * @see self::catch()
      */
@@ -135,7 +138,7 @@ public function otherwise(callable $onRejected): PromiseInterface;
      * ```
      *
      * @param callable $onFulfilledOrRejected
-     * @return PromiseInterface
+     * @return PromiseInterface<T>
      * @deprecated 3.0.0 Use finally() instead
      * @see self::finally()
      */
diff --git a/src/functions.php b/src/functions.php
index c42b715e..92a3d355 100644
--- a/src/functions.php
+++ b/src/functions.php
@@ -17,8 +17,9 @@
  *
  * If `$promiseOrValue` is a promise, it will be returned as is.
  *
- * @param mixed $promiseOrValue
- * @return PromiseInterface
+ * @template T
+ * @param PromiseInterface<T>|T $promiseOrValue
+ * @return PromiseInterface<T>
  */
 function resolve($promiseOrValue): PromiseInterface
 {
@@ -30,7 +31,9 @@ function resolve($promiseOrValue): PromiseInterface
         $canceller = null;
 
         if (\method_exists($promiseOrValue, 'cancel')) {
-            $canceller = [$promiseOrValue, 'cancel'];
+            $canceller = static function () use ($promiseOrValue) {
+                $promiseOrValue->cancel();
+            };
         }
 
         return new Promise(function ($resolve, $reject) use ($promiseOrValue): void {
@@ -54,8 +57,7 @@ function resolve($promiseOrValue): PromiseInterface
  * throwing an exception. For example, it allows you to propagate a rejection with
  * the value of another promise.
  *
- * @param \Throwable $reason
- * @return PromiseInterface
+ * @return PromiseInterface<null>
  */
 function reject(\Throwable $reason): PromiseInterface
 {
@@ -68,8 +70,9 @@ function reject(\Throwable $reason): PromiseInterface
  * will be an array containing the resolution values of each of the items in
  * `$promisesOrValues`.
  *
- * @param iterable<mixed> $promisesOrValues
- * @return PromiseInterface
+ * @template T
+ * @param array<PromiseInterface<T>|T> $promisesOrValues
+ * @return PromiseInterface<array<T>>
  */
 function all(iterable $promisesOrValues): PromiseInterface
 {
@@ -87,7 +90,7 @@ function all(iterable $promisesOrValues): PromiseInterface
             ++$toResolve;
 
             resolve($promiseOrValue)->then(
-                function ($value) use ($i, &$values, &$toResolve, &$continue, $resolve): void {
+                function ($value) use ($i, &$values, &$toResolve, &$continue, $resolve): void { /** @phpstan-ignore-line */
                     $values[$i] = $value;
 
                     if (0 === --$toResolve && !$continue) {
@@ -119,8 +122,9 @@ function (\Throwable $reason) use (&$continue, $reject): void {
  * The returned promise will become **infinitely pending** if  `$promisesOrValues`
  * contains 0 items.
  *
- * @param iterable<mixed> $promisesOrValues
- * @return PromiseInterface
+ * @template T
+ * @param array<PromiseInterface<T>|T> $promisesOrValues
+ * @return PromiseInterface<T>
  */
 function race(iterable $promisesOrValues): PromiseInterface
 {
@@ -132,7 +136,7 @@ function race(iterable $promisesOrValues): PromiseInterface
         foreach ($promisesOrValues as $promiseOrValue) {
             $cancellationQueue->enqueue($promiseOrValue);
 
-            resolve($promiseOrValue)->then($resolve, $reject)->finally(function () use (&$continue): void {
+            resolve($promiseOrValue)->then($resolve, $reject)->finally(function () use (&$continue): void { /** @phpstan-ignore-line */
                 $continue = false;
             });
 
@@ -154,8 +158,9 @@ function race(iterable $promisesOrValues): PromiseInterface
  * The returned promise will also reject with a `React\Promise\Exception\LengthException`
  * if `$promisesOrValues` contains 0 items.
  *
- * @param iterable<mixed> $promisesOrValues
- * @return PromiseInterface
+ * @template T
+ * @param array<PromiseInterface<T>|T> $promisesOrValues
+ * @return PromiseInterface<T>
  */
 function any(iterable $promisesOrValues): PromiseInterface
 {
@@ -171,7 +176,7 @@ function any(iterable $promisesOrValues): PromiseInterface
             ++$toReject;
 
             resolve($promiseOrValue)->then(
-                function ($value) use ($resolve, &$continue): void {
+                function ($value) use ($resolve, &$continue): void { /** @phpstan-ignore-line */
                     $continue = false;
                     $resolve($value);
                 },
diff --git a/tests/Internal/CancellationQueueTest.php b/tests/Internal/CancellationQueueTest.php
index c2907f73..3d802540 100644
--- a/tests/Internal/CancellationQueueTest.php
+++ b/tests/Internal/CancellationQueueTest.php
@@ -96,7 +96,7 @@ public function rethrowsExceptionsThrownFromCancel(): void
         $cancellationQueue();
     }
 
-    private function getCancellableDeferred(): Deferred
+    private function getCancellableDeferred(): Deferred /** @phpstan-ignore-line */
     {
         return new Deferred($this->expectCallableOnce());
     }
diff --git a/tests/Internal/FulfilledPromiseTest.php b/tests/Internal/FulfilledPromiseTest.php
index 073b9d7a..390ffad0 100644
--- a/tests/Internal/FulfilledPromiseTest.php
+++ b/tests/Internal/FulfilledPromiseTest.php
@@ -9,6 +9,9 @@
 use React\Promise\PromiseTest\PromiseSettledTestTrait;
 use React\Promise\TestCase;
 
+/**
+ * @template T
+ */
 class FulfilledPromiseTest extends TestCase
 {
     use PromiseSettledTestTrait,
@@ -16,7 +19,7 @@ class FulfilledPromiseTest extends TestCase
 
     public function getPromiseTestAdapter(callable $canceller = null): CallbackPromiseAdapter
     {
-        /** @var ?FulfilledPromise */
+        /** @var ?FulfilledPromise<T> */
         $promise = null;
 
         return new CallbackPromiseAdapter([
diff --git a/tests/Internal/RejectedPromiseTest.php b/tests/Internal/RejectedPromiseTest.php
index 72cef091..e37c8612 100644
--- a/tests/Internal/RejectedPromiseTest.php
+++ b/tests/Internal/RejectedPromiseTest.php
@@ -5,10 +5,14 @@
 use Exception;
 use LogicException;
 use React\Promise\PromiseAdapter\CallbackPromiseAdapter;
+use React\Promise\PromiseInterface;
 use React\Promise\PromiseTest\PromiseRejectedTestTrait;
 use React\Promise\PromiseTest\PromiseSettledTestTrait;
 use React\Promise\TestCase;
 
+/**
+ * @template T
+ */
 class RejectedPromiseTest extends TestCase
 {
     use PromiseSettledTestTrait,
@@ -16,7 +20,7 @@ class RejectedPromiseTest extends TestCase
 
     public function getPromiseTestAdapter(callable $canceller = null): CallbackPromiseAdapter
     {
-        /** @var ?RejectedPromise */
+        /** @var ?RejectedPromise<T> */
         $promise = null;
 
         return new CallbackPromiseAdapter([
diff --git a/tests/PromiseAdapter/CallbackPromiseAdapter.php b/tests/PromiseAdapter/CallbackPromiseAdapter.php
index 14a0acd4..aec72949 100644
--- a/tests/PromiseAdapter/CallbackPromiseAdapter.php
+++ b/tests/PromiseAdapter/CallbackPromiseAdapter.php
@@ -17,6 +17,9 @@ public function __construct(array $callbacks)
         $this->callbacks = $callbacks;
     }
 
+    /**
+     * @phpstan-ignore-next-line
+     */
     public function promise(): PromiseInterface
     {
         return ($this->callbacks['promise'])(...func_get_args());
diff --git a/tests/PromiseAdapter/PromiseAdapterInterface.php b/tests/PromiseAdapter/PromiseAdapterInterface.php
index 727fd514..0eaa2dcb 100644
--- a/tests/PromiseAdapter/PromiseAdapterInterface.php
+++ b/tests/PromiseAdapter/PromiseAdapterInterface.php
@@ -6,6 +6,9 @@
 
 interface PromiseAdapterInterface
 {
+    /**
+     * @phpstan-ignore-next-line
+     */
     public function promise(): PromiseInterface;
     public function resolve(): void;
     public function reject(): void;
diff --git a/tests/PromiseTest/PromiseFulfilledTestTrait.php b/tests/PromiseTest/PromiseFulfilledTestTrait.php
index d982214a..be5e7429 100644
--- a/tests/PromiseTest/PromiseFulfilledTestTrait.php
+++ b/tests/PromiseTest/PromiseFulfilledTestTrait.php
@@ -191,7 +191,7 @@ public function thenShouldContinueToExecuteCallbacksWhenPriorCallbackSuspendsFib
         $adapter->resolve(42);
 
         $fiber = new \Fiber(function () use ($adapter) {
-            $adapter->promise()->then(function (int $value) {
+            $adapter->promise()->then(function (int $value) { /** @phpstan-ignore-line */
                 \Fiber::suspend($value);
             });
         });
diff --git a/tests/PromiseTest/RejectTestTrait.php b/tests/PromiseTest/RejectTestTrait.php
index ad55ca28..12f6031f 100644
--- a/tests/PromiseTest/RejectTestTrait.php
+++ b/tests/PromiseTest/RejectTestTrait.php
@@ -73,7 +73,7 @@ public function rejectShouldMakePromiseImmutable(): void
             ->with($this->identicalTo($exception1));
 
         $adapter->promise()
-            ->then(null, function ($value) use ($exception3, $adapter) {
+            ->then(null, function (\Throwable $value) use ($exception3, $adapter) {
                 $adapter->reject($exception3);
 
                 return reject($value);
diff --git a/types/Promises.php b/types/Promises.php
new file mode 100644
index 00000000..e62c15c9
--- /dev/null
+++ b/types/Promises.php
@@ -0,0 +1,79 @@
+<?php
+
+use React\Promise\Internal\FulfilledPromise;
+use React\Promise\PromiseInterface;
+
+use function PHPStan\Testing\assertType;
+use function React\Promise\all;
+use function React\Promise\any;
+use function React\Promise\race;
+use function React\Promise\reject;
+use function React\Promise\resolve;
+
+$passThroughBoolFn = static function (bool $bool): bool {
+    return $bool;
+};
+$passThroughThrowable = static function (Throwable $t): PromiseInterface {
+    return reject($t);
+};
+/**
+ * @return int|string
+ */
+$stringOrInt = function () {
+    return time() % 2 ? 'string' : time();
+};
+$tosseable = new Exception('Oops I did it again!');
+
+/**
+ * basic
+ */
+assertType('React\Promise\PromiseInterface<bool>', resolve(true));
+assertType('React\Promise\PromiseInterface<int|string>', resolve($stringOrInt()));
+assertType('React\Promise\PromiseInterface<bool>', resolve(resolve(true)));
+
+/**
+ * chaining
+ */
+assertType('React\Promise\PromiseInterface<bool>', resolve(true)->then($passThroughBoolFn));
+assertType('React\Promise\PromiseInterface<bool>', resolve(true)->then()->then($passThroughBoolFn));
+assertType('React\Promise\PromiseInterface<bool>', resolve(true)->then(null)->then($passThroughBoolFn));
+assertType('React\Promise\PromiseInterface<bool>', resolve(true)->then($passThroughBoolFn)->then($passThroughBoolFn));
+assertType('React\Promise\PromiseInterface<bool>', resolve(true)->then($passThroughBoolFn, $passThroughThrowable)->then($passThroughBoolFn));
+assertType('React\Promise\PromiseInterface<bool>', resolve(true)->then(null, $passThroughThrowable)->then($passThroughBoolFn));
+assertType('React\Promise\PromiseInterface<bool>', resolve(true)->then()->then(null, $passThroughThrowable)->then($passThroughBoolFn));
+
+/**
+ * all
+ */
+assertType('React\Promise\PromiseInterface<array<bool>>', all([resolve(true), resolve(false)]));
+assertType('React\Promise\PromiseInterface<array<bool>>', all([resolve(true), false]));
+assertType('React\Promise\PromiseInterface<array<bool|int>>', all([true, time()]));
+assertType('React\Promise\PromiseInterface<array<bool|int>>', all([resolve(true), resolve(time())]));
+//assertType('React\Promise\PromiseInterface<array<bool|float>>', all([resolve(true), microtime(true)]));
+//assertType('React\Promise\PromiseInterface<array<bool|int>>', all([true, resolve(time())]));
+
+/**
+ * any
+ */
+assertType('React\Promise\PromiseInterface<bool>', any([resolve(true), resolve(false)]));
+assertType('React\Promise\PromiseInterface<bool>', any([resolve(true), false]));
+assertType('React\Promise\PromiseInterface<bool|int>', any([true, time()]));
+assertType('React\Promise\PromiseInterface<bool|int>', any([resolve(true), resolve(time())]));
+//assertType('React\Promise\PromiseInterface<bool|float>', any([resolve(true), microtime(true)]));
+//assertType('React\Promise\PromiseInterface<bool|int>', any([true, resolve(time())]));
+
+/**
+ * race
+ */
+assertType('React\Promise\PromiseInterface<bool>', race([resolve(true), resolve(false)]));
+assertType('React\Promise\PromiseInterface<bool>', race([resolve(true), false]));
+assertType('React\Promise\PromiseInterface<bool|int>', race([true, time()]));
+assertType('React\Promise\PromiseInterface<bool|int>', race([resolve(true), resolve(time())]));
+//assertType('React\Promise\PromiseInterface<bool|float>', race([resolve(true), microtime(true)]));
+//assertType('React\Promise\PromiseInterface<bool|int>', race([true, resolve(time())]));
+
+/**
+ * direct class access (deprecated!!!)
+ */
+assertType('React\Promise\Internal\FulfilledPromise<bool>', new FulfilledPromise(true));
+//assertType('React\Promise\PromiseInterface<bool>', (new FulfilledPromise(true))->then($passThroughBoolFn));