diff --git a/lib/functions.php b/lib/functions.php
index 0fde36c..3a6a228 100644
--- a/lib/functions.php
+++ b/lib/functions.php
@@ -59,10 +59,10 @@ namespace Amp
         Loop::defer(static fn () => \Fiber::run(static function () use ($deferred, $callback, $args): void {
             try {
                 $deferred->resolve($callback(...$args));
-            } catch (\Throwable $e) {
-                $deferred->fail($e);
+            } catch (\Throwable $exception) {
+                $deferred->fail($exception);
             }
-        }, ...$args));
+        }));
 
         return $deferred->promise();
     }
@@ -874,10 +874,10 @@ namespace Amp\Pipeline
     use Amp\PipelineSource;
     use Amp\Promise;
     use React\Promise\PromiseInterface as ReactPromise;
+    use function Amp\async;
+    use function Amp\asyncCallable;
     use function Amp\await;
-    use function Amp\call;
-    use function Amp\coroutine;
-    use function Amp\delay;
+    use function Amp\sleep;
     use function Amp\Internal\createTypeError;
 
     /**
@@ -902,7 +902,7 @@ namespace Amp\Pipeline
         return new AsyncGenerator(static function () use ($iterable, $delay): \Generator {
             foreach ($iterable as $value) {
                 if ($delay) {
-                    await(delay($delay));
+                    sleep($delay);
                 }
 
                 if ($value instanceof Promise || $value instanceof ReactPromise) {
@@ -971,9 +971,9 @@ namespace Amp\Pipeline
         $source = new PipelineSource;
         $result = $source->pipe();
 
-        $coroutine = coroutine(static function (Pipeline $stream) use (&$source) {
-            while ((null !== $value = yield $stream->continue()) && $source !== null) {
-                yield $source->emit($value);
+        $coroutine = asyncCallable(static function (Pipeline $stream) use (&$source) {
+            while ((null !== $value = $stream->continue()) && $source !== null) {
+                $source->yield($value);
             }
         });
 
@@ -1039,10 +1039,10 @@ namespace Amp\Pipeline
      */
     function discard(Pipeline $pipeline): Promise
     {
-        return call(static function () use ($stream): \Generator {
+        return async(static function () use ($pipeline): int {
             $count = 0;
 
-            while (null !== yield $stream->continue()) {
+            while (null !== $pipeline->continue()) {
                 $count++;
             }