WIP

Author: WyriHaximus

src/PromiseInterface.php

@@ -3,8 +3,8 @@
 namespace React\Promise;
 
 /**
- * @template T
- * @template R
+ * @template-covariant T
+ * @template-covariant R
  */
 interface PromiseInterface
 {
@@ -36,15 +36,11 @@ interface PromiseInterface
      *      than once.
      *  3. `$onProgress` (deprecated) may be called multiple times.
      *
-     * @template TFulfilled of mixed
-     * @template TRejected of mixed
-     * @param (callable(T): (PromiseInterface<TFulfilled>|TFulfilled))|null $onFulfilled
-     * @param (callable(R): (PromiseInterface<TRejected>|TRejected))|null $onRejected
-     * @return PromiseInterface<(
-     *   $onFulfilled is not null
-     *     ? ($onRejected is not null ? TFulfilled|TRejected : TFulfilled)
-     *     : ($onRejected is not null ? TRejected : R)
-     * )>
+     * @template TFulfilled as PromiseInterface<T>|T
+     * @template TRejected as \Throwable
+     * @param callable(T): TFulfilled $onFulfilled
+     * @param callable(R): TRejected $onRejected
+     * @return (TFulfilled is PromiseInterface ? TFulfilled : PromiseInterface<TFulfilled, TRejected>)
      */
     public function then(callable $onFulfilled = null, callable $onRejected = null, callable $onProgress = null);
 }

src/functions.php

@@ -15,7 +15,7 @@
  *
  * @template T
  * @param T $promiseOrValue
- * @return PromiseInterface<T>
+ * @return (T is PromiseInterface ? T : PromiseInterface<T>)
  */
 function resolve($promiseOrValue = null)
 {
@@ -53,8 +53,10 @@ function resolve($promiseOrValue = null)
  * throwing an exception. For example, it allows you to propagate a rejection with
  * the value of another promise.
  *
- * @param mixed $promiseOrValue
- * @return PromiseInterface
+ * @template T is null
+ * @template R
+ * @param R $promiseOrValue
+ * @return (R is PromiseInterface ? R : PromiseInterface<T, R>)
  */
 function reject($promiseOrValue = null)
 {

types/Promises.php

@@ -14,27 +14,34 @@
 $passThroughThrowable = static function (Throwable $t): PromiseInterface {
     return reject($t);
 };
+$stringOrInt = function (): string|int {
+  return time() % 2 ? 'string' : time();
+};
 $tosseable = new Exception('Oops I did it again!');
 
 assertType('React\Promise\PromiseInterface<bool>', resolve(true));
-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([resolve(true), resolve(time())]));
-assertType('React\Promise\PromiseInterface<array<bool|int>>', all([resolve(true), time()]));
-assertType('React\Promise\PromiseInterface<array<bool|int>>', all([true, resolve(time())]));
-assertType('React\Promise\PromiseInterface<bool>', race([resolve(true), resolve(true)]));
-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<string|int>', resolve($stringOrInt()));
+assertType('React\Promise\PromiseInterface<int|string>', resolve($stringOrInt()));
+assertType('React\Promise\PromiseInterface<bool>', resolve(resolve(true)));
+//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([resolve(true), resolve(time())]));
+//assertType('React\Promise\PromiseInterface<array<bool|float>>', all([resolve(true), hrtime()]));
+//assertType('React\Promise\PromiseInterface<array<bool|int>>', all([true, resolve(time())]));
+//assertType('React\Promise\PromiseInterface<bool>', race([resolve(true), resolve(true)]));
+//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));
-assertType('React\Promise\FulfilledPromise<bool>', new FulfilledPromise(true));
-assertType('React\Promise\PromiseInterface<bool>', (new FulfilledPromise(true))->then($passThroughBoolFn));
+//assertType('React\Promise\PromiseInterface<bool>', resolve(true)->then()->then(null, $passThroughThrowable)->then($passThroughBoolFn));
+//assertType('React\Promise\FulfilledPromise<bool>', new FulfilledPromise(true));
+//assertType('React\Promise\PromiseInterface<bool>', (new FulfilledPromise(true))->then($passThroughBoolFn));
 
-//assertType('React\Promise\PromiseInterface<Throwable>', reject($tosseable));
-//assertType('React\Promise\PromiseInterface<Throwable>', reject($tosseable)->then($passThroughBoolFn, $passThroughThrowable));
-//assertType('React\Promise\PromiseInterface<Throwable>', reject($tosseable)->then()->then($passThroughBoolFn, $passThroughThrowable));
-//assertType('React\Promise\PromiseInterface<Throwable>', reject($tosseable)->then(null, $passThroughThrowable));
-//assertType('React\Promise\PromiseInterface<Throwable>', reject($tosseable)->then()->then(null, $passThroughThrowable));
+//assertType('React\Promise\PromiseInterface<null, Exception>', reject($tosseable));
+//assertType('React\Promise\PromiseInterface<null, Throwable>', reject($tosseable));
+//assertType('React\Promise\PromiseInterface<null, Throwable>', reject($tosseable)->then($passThroughBoolFn, $passThroughThrowable));
+//assertType('React\Promise\PromiseInterface<null, Throwable>', reject($tosseable)->then()->then($passThroughBoolFn, $passThroughThrowable));
+//assertType('React\Promise\PromiseInterface<null, Throwable>', reject($tosseable)->then(null, $passThroughThrowable));
+//assertType('React\Promise\PromiseInterface<null, Throwable>', reject($tosseable)->then()->then(null, $passThroughThrowable));