Fixing PHPStan level 9 issues

Author: gplanchat

src/GeneratorWrapper.php

@@ -11,23 +11,23 @@
  */
 class GeneratorWrapper
 {
-    /** @param \Iterator<mixed, mixed> ...$iterators */
+    /** @param \Iterator<array-key, Type> ...$iterators */
     public function rewind(\Iterator ...$iterators): void
     {
         foreach ($iterators as $iterator) {
             $iterator->rewind();
         }
     }
 
-    /** @param \Iterator<mixed, mixed> ...$iterators */
+    /** @param \Iterator<array-key, Type> ...$iterators */
     public function next(\Iterator ...$iterators): void
     {
         foreach ($iterators as $iterator) {
             $iterator->next();
         }
     }
 
-    /** @param \Iterator<mixed, mixed> ...$iterators */
+    /** @param \Iterator<array-key, Type> ...$iterators */
     public function valid(\Iterator ...$iterators): bool
     {
         foreach ($iterators as $iterator) {
@@ -41,7 +41,7 @@ public function valid(\Iterator ...$iterators): bool
 
     /**
      * @param Type $value
-     * @param \Generator<array-key, ResultBucketInterface<Type>, Type|null, void> ...$generators
+     * @param \Generator<array-key, ResultBucketInterface<Type>, Type, void> ...$generators
      */
     public function send($value, \Generator ...$generators): \Generator
     {

src/Pipeline.php

@@ -27,9 +27,6 @@ class Pipeline implements PipelineInterface, WalkableInterface, RunnableInterfac
     /** @var iterable<mixed>|\NoRewindIterator */
     private iterable $subject;
 
-    /**
-     * @param PipelineRunnerInterface<mixed> $runner
-     */
     public function __construct(
         private readonly PipelineRunnerInterface $runner,
         private readonly StateInterface $state,
@@ -49,6 +46,7 @@ public function feed(...$data): void
     private function passThroughCoroutine(): \Generator
     {
         $line = yield;
+        /** @phpstan-ignore-next-line */
         while (true) {
             $line = yield $line;
         }

src/PipelineRunner.php

@@ -18,11 +18,6 @@
 use Psr\Log\LogLevel;
 use Psr\Log\NullLogger;
 
-/**
- * @template Type
- *
- * @implements PipelineRunnerInterface<Type>
- */
 class PipelineRunner implements PipelineRunnerInterface
 {
     public function __construct(
@@ -52,9 +47,13 @@ public function run(
             }
 
             if ($bucket instanceof RejectionResultBucketInterface) {
+                $reasons = $bucket->reasons();
                 foreach ($bucket->walkRejection() as $line) {
-                    $rejection->reject($line);
-                    $rejection->rejectWithReason($line, implode('', $bucket->reasons()));
+                    if ($reasons !== null) {
+                        $rejection->rejectWithReason($line, implode(PHP_EOL, $reasons));
+                    } else {
+                        $rejection->reject($line);
+                    }
                     $state->reject();
 
                     $this->logger->log(