Describe callable arguments for Deferred

Author: clue

src/Deferred.php

@@ -12,12 +12,15 @@ final class Deferred
      */
     private $promise;
 
-    /** @var callable */
+    /** @var callable(T):void */
     private $resolveCallback;
 
-    /** @var callable */
+    /** @var callable(\Throwable):void */
     private $rejectCallback;
 
+    /**
+     * @param (callable(callable(T):void,callable(\Throwable):void):void)|null $canceller
+     */
     public function __construct(callable $canceller = null)
     {
         $this->promise = new Promise(function ($resolve, $reject): void {

tests/Internal/CancellationQueueTest.php

@@ -101,6 +101,7 @@ public function rethrowsExceptionsThrownFromCancel(): void
      */
     private function getCancellableDeferred(): Deferred
     {
+        /** @var Deferred<never> */
         return new Deferred($this->expectCallableOnce());
     }
 }

tests/types/deferred.php

@@ -10,3 +10,40 @@
 $deferredB = new Deferred();
 $deferredB->resolve(42);
 assertType('React\Promise\PromiseInterface<int>', $deferredB->promise());
+
+// $deferred = new Deferred();
+// $deferred->resolve(42);
+// assertType('React\Promise\Deferred<int>', $deferred);
+
+// $deferred = new Deferred();
+// $deferred->resolve(true);
+// $deferred->resolve('ignored');
+// assertType('React\Promise\Deferred<bool>', $deferred);
+
+// $deferred = new Deferred();
+// $deferred->reject(new \RuntimeException());
+// assertType('React\Promise\Deferred<never>', $deferred);
+
+// invalid number of arguments passed to $canceller
+/** @phpstan-ignore-next-line */
+$deferred = new Deferred(function ($a, $b, $c) { });
+assertType('React\Promise\Deferred<mixed>', $deferred);
+
+// invalid types for arguments of $canceller
+/** @phpstan-ignore-next-line */
+$deferred = new Deferred(function (int $a, string $b) { });
+assertType('React\Promise\Deferred<mixed>', $deferred);
+
+// invalid number of arguments passed to $resolve
+$deferred = new Deferred(function (callable $resolve) {
+    /** @phpstan-ignore-next-line */
+    $resolve();
+});
+assertType('React\Promise\Deferred<mixed>', $deferred);
+
+// invalid type passed to $reject
+$deferred = new Deferred(function (callable $resolve, callable $reject) {
+    /** @phpstan-ignore-next-line */
+    $reject(2);
+});
+assertType('React\Promise\Deferred<mixed>', $deferred);