Make implicit nullable types explicit

.php-cs-fixer.dist.php

@@ -10,6 +10,7 @@
         'no_superfluous_phpdoc_tags' => [
             'allow_mixed' => true,
         ],
+        'nullable_type_declaration_for_default_null_value' => true,
         'phpdoc_annotation_without_dot' => false,
         'phpdoc_summary' => false,
         'phpdoc_to_comment' => false,

src/Coroutine.php

@@ -84,8 +84,8 @@ public static function of(callable $generatorFn): self
     }
 
     public function then(
-        callable $onFulfilled = null,
-        callable $onRejected = null
+        ?callable $onFulfilled = null,
+        ?callable $onRejected = null
     ): PromiseInterface {
         return $this->result->then($onFulfilled, $onRejected);
     }

src/Each.php

@@ -23,8 +23,8 @@ final class Each
      */
     public static function of(
         $iterable,
-        callable $onFulfilled = null,
-        callable $onRejected = null
+        ?callable $onFulfilled = null,
+        ?callable $onRejected = null
     ): PromiseInterface {
         return (new EachPromise($iterable, [
             'fulfilled' => $onFulfilled,
@@ -46,8 +46,8 @@ public static function of(
     public static function ofLimit(
         $iterable,
         $concurrency,
-        callable $onFulfilled = null,
-        callable $onRejected = null
+        ?callable $onFulfilled = null,
+        ?callable $onRejected = null
     ): PromiseInterface {
         return (new EachPromise($iterable, [
             'fulfilled' => $onFulfilled,
@@ -67,7 +67,7 @@ public static function ofLimit(
     public static function ofLimitAll(
         $iterable,
         $concurrency,
-        callable $onFulfilled = null
+        ?callable $onFulfilled = null
     ): PromiseInterface {
         return self::ofLimit(
             $iterable,

src/FulfilledPromise.php

@@ -31,8 +31,8 @@ public function __construct($value)
     }
 
     public function then(
-        callable $onFulfilled = null,
-        callable $onRejected = null
+        ?callable $onFulfilled = null,
+        ?callable $onRejected = null
     ): PromiseInterface {
         // Return itself if there is no onFulfilled function.
         if (!$onFulfilled) {

src/Promise.php

@@ -25,16 +25,16 @@ class Promise implements PromiseInterface
      * @param callable $cancelFn Fn that when invoked cancels the promise.
      */
     public function __construct(
-        callable $waitFn = null,
-        callable $cancelFn = null
+        ?callable $waitFn = null,
+        ?callable $cancelFn = null
     ) {
         $this->waitFn = $waitFn;
         $this->cancelFn = $cancelFn;
     }
 
     public function then(
-        callable $onFulfilled = null,
-        callable $onRejected = null
+        ?callable $onFulfilled = null,
+        ?callable $onRejected = null
     ): PromiseInterface {
         if ($this->state === self::PENDING) {
             $p = new Promise(null, [$this, 'cancel']);

src/PromiseInterface.php

@@ -27,8 +27,8 @@ interface PromiseInterface
      * @param callable $onRejected  Invoked when the promise is rejected.
      */
     public function then(
-        callable $onFulfilled = null,
-        callable $onRejected = null
+        ?callable $onFulfilled = null,
+        ?callable $onRejected = null
     ): PromiseInterface;
 
     /**

src/RejectedPromise.php

@@ -31,8 +31,8 @@ public function __construct($reason)
     }
 
     public function then(
-        callable $onFulfilled = null,
-        callable $onRejected = null
+        ?callable $onFulfilled = null,
+        ?callable $onRejected = null
     ): PromiseInterface {
         // If there's no onRejected callback then just return self.
         if (!$onRejected) {

src/RejectionException.php

@@ -18,7 +18,7 @@ class RejectionException extends \RuntimeException
      * @param mixed       $reason      Rejection reason.
      * @param string|null $description Optional description.
      */
-    public function __construct($reason, string $description = null)
+    public function __construct($reason, ?string $description = null)
     {
         $this->reason = $reason;
 

src/Utils.php

@@ -21,7 +21,7 @@ final class Utils
      *
      * @param TaskQueueInterface|null $assign Optionally specify a new queue instance.
      */
-    public static function queue(TaskQueueInterface $assign = null): TaskQueueInterface
+    public static function queue(?TaskQueueInterface $assign = null): TaskQueueInterface
     {
         static $queue;
 

tests/CoroutineTest.php

@@ -103,7 +103,7 @@ public function testWaitShouldHandleIntermediateErrors(): void
                 });
             });
         })
-        ->otherwise(function (\Exception $error = null) {
+        ->otherwise(function (?\Exception $error = null) {
             if (!$error) {
                 self::fail('Error did not propagate.');
             }

tests/NotPromiseInstance.php

@@ -16,7 +16,7 @@ public function __construct()
         $this->nextPromise = new Promise();
     }
 
-    public function then(callable $res = null, callable $rej = null): PromiseInterface
+    public function then(?callable $res = null, ?callable $rej = null): PromiseInterface
     {
         return $this->nextPromise->then($res, $rej);
     }
@@ -36,7 +36,7 @@ public function reject($reason): void
         $this->nextPromise->reject($reason);
     }
 
-    public function wait(bool $unwrap = true, bool $defaultResolution = null): void
+    public function wait(bool $unwrap = true, ?bool $defaultResolution = null): void
     {
     }
 

tests/Thennable.php

@@ -15,7 +15,7 @@ public function __construct()
         $this->nextPromise = new Promise();
     }
 
-    public function then(callable $res = null, callable $rej = null)
+    public function then(?callable $res = null, ?callable $rej = null)
     {
         return $this->nextPromise->then($res, $rej);
     }