diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7a8ae6b0..bdf7f535 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,10 @@ Latest
 
 ## Changes
 * [#197](https://github.com/cleverage/process-bundle/issues/197) Add missing tests: every Task and Transformer is now covered by unit tests. Remove the obsolete `tests.old` directory.
+* [#143](https://github.com/cleverage/process-bundle/issues/143) Improve PHPStan configuration: remove all `ignoreErrors` and `@phpstan-ignore` comments (report unmatched ignored errors again), add missing iterable value types and generic types in PHPDoc, remove unreachable code in AbstractIterableOutputTask and InputAggregatorTask.
+
+## Fixes
+* [#143](https://github.com/cleverage/process-bundle/issues/143) Fix InputIteratorTask: an `\IteratorAggregate` input whose `getIterator()` does not return an `\Iterator` (e.g. another `\IteratorAggregate`) is iterated instead of failing with a `TypeError`. Update documentation, add tests.
 
 v5.1
 -----
diff --git a/docs/reference/tasks/input_iterator_task.md b/docs/reference/tasks/input_iterator_task.md
index 6451f86d..2d4407ce 100644
--- a/docs/reference/tasks/input_iterator_task.md
+++ b/docs/reference/tasks/input_iterator_task.md
@@ -12,7 +12,7 @@ Task reference
 Accepted inputs
 ---------------
 
-`array`, `\Iterator` or `\IteratorAggregate`: any other type throws an `\UnexpectedValueException`
+`array`, `\Iterator` or `\IteratorAggregate` (whatever `\Traversable` its `getIterator()` returns): any other type throws an `\UnexpectedValueException`
 
 Possible outputs
 ----------------
diff --git a/phpstan.neon b/phpstan.neon
index f0560a73..337ea110 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -5,16 +5,5 @@ parameters:
         - tests
     excludePaths:
         - src/Resources/tests/*
-    ignoreErrors:
-        - '#type has no value type specified in iterable type#'
-        - '#has parameter .* with no value type specified in iterable type#'
-        - '#has no value type specified in iterable type array#'
-        - '#configureOptions\(\) has no return type specified.#'
-        - '#configure\(\) has no return type specified#'
-        - '#process\(\) has no return type specified#'
-        - '#should return Iterator but returns Traversable#'
-        - '#Negated boolean expression is always false#'
-        - identifier: missingType.generics
-    reportUnmatchedIgnoredErrors: false
     inferPrivatePropertyTypeFromConstructor: true
     treatPhpDocTypesAsCertain: false
diff --git a/src/Command/ListProcessCommand.php b/src/Command/ListProcessCommand.php
index 01fdf997..4837bda4 100644
--- a/src/Command/ListProcessCommand.php
+++ b/src/Command/ListProcessCommand.php
@@ -48,6 +48,9 @@ public function processSorter(ProcessConfiguration $a, ProcessConfiguration $b):
         return $a->getCode() <=> $b->getCode();
     }
 
+    /**
+     * @param array{output: string} $message
+     */
     public function maxMessageLengthFilter(int $max, array $message): int
     {
         return max($max, \strlen($this->filterOutTags($message['output'])));
diff --git a/src/Command/ProcessHelpCommand.php b/src/Command/ProcessHelpCommand.php
index ea22e351..5864ffad 100644
--- a/src/Command/ProcessHelpCommand.php
+++ b/src/Command/ProcessHelpCommand.php
@@ -126,6 +126,9 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 
     /**
      * Try to find a best candidate for next display.
+     *
+     * @param array<string|null> $branches
+     * @param list<string>       $taskList
      */
     protected function findBestNextTask(
         array $branches,
@@ -223,6 +226,8 @@ protected function getTaskChildrenCount(TaskConfiguration $task): int
 
     /**
      * Merge needed branches, display a task node, split following needed branches.
+     *
+     * @param array<string|null> $branches
      */
     protected function resolveBranchOutput(
         array &$branches,
@@ -442,6 +447,10 @@ static function ($branchTask, $i) use ($origin, $branches, $gapBranches, $final)
         $this->writeBranches($output, $branches);
     }
 
+    /**
+     * @param array<string|null>      $branches
+     * @param string|iterable<string> $comment
+     */
     protected function writeBranches(
         OutputInterface $output,
         array $branches,
diff --git a/src/Configuration/ProcessConfiguration.php b/src/Configuration/ProcessConfiguration.php
index 48d9caa8..b62aa723 100644
--- a/src/Configuration/ProcessConfiguration.php
+++ b/src/Configuration/ProcessConfiguration.php
@@ -21,10 +21,20 @@
  */
 class ProcessConfiguration
 {
+    /**
+     * @var list<list<string>>|null
+     */
     protected ?array $dependencyGroups = null;
 
+    /**
+     * @var list<string>|null
+     */
     protected ?array $mainTaskGroup = null;
 
+    /**
+     * @param array<string, TaskConfiguration> $taskConfigurations
+     * @param array<string, mixed>             $options
+     */
     public function __construct(
         protected string $code,
         protected array $taskConfigurations,
@@ -42,6 +52,9 @@ public function getCode(): string
         return $this->code;
     }
 
+    /**
+     * @return array<string, mixed>
+     */
     public function getOptions(): array
     {
         return $this->options;
@@ -106,6 +119,8 @@ public function getTaskConfiguration(string $taskCode): TaskConfiguration
      * Group all task by dependencies.
      *
      * If one task depend from another, it should come after
+     *
+     * @return list<list<string>>
      */
     public function getDependencyGroups(): array
     {
@@ -130,6 +145,8 @@ public function getDependencyGroups(): array
      * It may be defined by the entry_point, or the end_point or simply the first task.
      *
      * If one task depend from another, it should come after
+     *
+     * @return list<string>
      */
     public function getMainTaskGroup(): array
     {
@@ -195,6 +212,10 @@ public function checkCircularDependencies(): void
 
     /**
      * Cross all relations of a task to find all dependencies, and append them to the given array.
+     *
+     * @param list<string> $dependencies
+     *
+     * @return list<string>
      */
     protected function buildDependencies(TaskConfiguration $taskConfig, array &$dependencies = []): array
     {
@@ -222,6 +243,10 @@ protected function buildDependencies(TaskConfiguration $taskConfig, array &$depe
 
     /**
      * Sort the tasks by dependencies.
+     *
+     * @param list<string> $dependencies
+     *
+     * @return list<string>
      */
     protected function sortDependencies(array $dependencies): array
     {
diff --git a/src/Configuration/TaskConfiguration.php b/src/Configuration/TaskConfiguration.php
index 1645939e..f6b167ce 100644
--- a/src/Configuration/TaskConfiguration.php
+++ b/src/Configuration/TaskConfiguration.php
@@ -49,6 +49,11 @@ class TaskConfiguration
 
     protected bool $logErrors;
 
+    /**
+     * @param array<string, mixed> $options
+     * @param list<string>         $outputs
+     * @param list<string>         $errorOutputs
+     */
     public function __construct(
         protected string $code,
         protected string $serviceReference,
@@ -93,6 +98,9 @@ public function getHelp(): string
         return $this->help;
     }
 
+    /**
+     * @return array<string, mixed>
+     */
     public function getOptions(): array
     {
         return $this->options;
@@ -107,11 +115,17 @@ public function getOption(string $code, mixed $default = null): mixed
         return $default;
     }
 
+    /**
+     * @return list<string>
+     */
     public function getOutputs(): array
     {
         return $this->outputs;
     }
 
+    /**
+     * @return list<string>
+     */
     #[\Deprecated(message: 'Use getErrorOutputs method instead')]
     public function getErrors(): array
     {
@@ -120,6 +134,9 @@ public function getErrors(): array
         return $this->getErrorOutputs();
     }
 
+    /**
+     * @return list<string>
+     */
     public function getErrorOutputs(): array
     {
         return $this->errorOutputs;
diff --git a/src/Context/ContextualOptionResolver.php b/src/Context/ContextualOptionResolver.php
index 067e3509..ef3014b4 100644
--- a/src/Context/ContextualOptionResolver.php
+++ b/src/Context/ContextualOptionResolver.php
@@ -18,6 +18,8 @@ class ContextualOptionResolver
     /**
      * Basic value inference
      * Replaces "{{ key }}" by context[key].
+     *
+     * @param array<string, mixed> $context
      */
     public function contextualizeOption(mixed $value, array $context): mixed
     {
@@ -46,6 +48,11 @@ public function contextualizeOption(mixed $value, array $context): mixed
 
     /**
      * Replace all contextualized values from options.
+     *
+     * @param array<string, mixed> $options
+     * @param array<string, mixed> $context
+     *
+     * @return array<string, mixed>
      */
     public function contextualizeOptions(array $options, array $context): array
     {
diff --git a/src/Event/ConsoleProcessEvent.php b/src/Event/ConsoleProcessEvent.php
index e404e071..317d0047 100644
--- a/src/Event/ConsoleProcessEvent.php
+++ b/src/Event/ConsoleProcessEvent.php
@@ -22,6 +22,9 @@
  */
 class ConsoleProcessEvent extends Event
 {
+    /**
+     * @param array<string, mixed> $processContext
+     */
     public function __construct(
         private readonly InputInterface $consoleInput,
         private readonly OutputInterface $consoleOutput,
@@ -45,6 +48,9 @@ public function getProcessInput(): mixed
         return $this->processInput;
     }
 
+    /**
+     * @return array<string, mixed>
+     */
     public function getProcessContext(): array
     {
         return $this->processContext;
diff --git a/src/Event/ProcessEvent.php b/src/Event/ProcessEvent.php
index 6c7b297f..7e9c8f53 100644
--- a/src/Event/ProcessEvent.php
+++ b/src/Event/ProcessEvent.php
@@ -26,6 +26,9 @@ class ProcessEvent extends Event
 
     final public const EVENT_PROCESS_FAILED = 'cleverage_process.fail';
 
+    /**
+     * @param array<string, mixed> $processContext
+     */
     public function __construct(
         protected string $processCode,
         protected mixed $processInput = null,
@@ -50,6 +53,9 @@ public function getProcessOutput(): mixed
         return $this->processOutput;
     }
 
+    /**
+     * @return array<string, mixed>
+     */
     public function getProcessContext(): array
     {
         return $this->processContext;
diff --git a/src/EventListener/DataQueueEventListener.php b/src/EventListener/DataQueueEventListener.php
index b405d886..2d0de8e1 100644
--- a/src/EventListener/DataQueueEventListener.php
+++ b/src/EventListener/DataQueueEventListener.php
@@ -14,6 +14,7 @@
 namespace CleverAge\ProcessBundle\EventListener;
 
 use CleverAge\ProcessBundle\Event\EventDispatcherTaskEvent;
+use CleverAge\ProcessBundle\Model\ProcessState;
 
 /**
  * Class DataQueueEventListener
@@ -23,7 +24,7 @@
 class DataQueueEventListener
 {
     /**
-     * @var \SplQueue[]
+     * @var array<string, \SplQueue<ProcessState>>
      */
     protected array $queues = [];
 
@@ -33,6 +34,9 @@ public function pushData(EventDispatcherTaskEvent $event): void
         $queue->push(clone $event->getState());
     }
 
+    /**
+     * @return \SplQueue<ProcessState>
+     */
     public function getQueue(string $processName): \SplQueue
     {
         if (!\array_key_exists($processName, $this->queues)) {
diff --git a/src/Exception/InvalidProcessConfigurationException.php b/src/Exception/InvalidProcessConfigurationException.php
index aecaab1f..3366fe24 100644
--- a/src/Exception/InvalidProcessConfigurationException.php
+++ b/src/Exception/InvalidProcessConfigurationException.php
@@ -21,6 +21,9 @@
  */
 class InvalidProcessConfigurationException extends \UnexpectedValueException implements ProcessExceptionInterface
 {
+    /**
+     * @param list<string> $mainTaskList
+     */
     public static function createNotInMain(
         ProcessConfiguration $processConfiguration,
         TaskConfiguration $taskConfig,
diff --git a/src/ExpressionLanguage/PhpFunctionProvider.php b/src/ExpressionLanguage/PhpFunctionProvider.php
index 9a2632b7..bd931429 100644
--- a/src/ExpressionLanguage/PhpFunctionProvider.php
+++ b/src/ExpressionLanguage/PhpFunctionProvider.php
@@ -21,6 +21,9 @@
  */
 class PhpFunctionProvider implements ExpressionFunctionProviderInterface
 {
+    /**
+     * @param list<string> $functions
+     */
     public function __construct(
         protected array $functions,
     ) {
diff --git a/src/Filesystem/CsvFile.php b/src/Filesystem/CsvFile.php
index d8944e87..5678c00a 100644
--- a/src/Filesystem/CsvFile.php
+++ b/src/Filesystem/CsvFile.php
@@ -19,10 +19,10 @@
 class CsvFile extends CsvResource
 {
     /**
-     * @param string $filePath  Also accept a resource
-     * @param string $delimiter CSV delimiter
-     * @param ?array $headers   Leave null to read the headers from the file
-     * @param string $mode      Same parameter as the mode in the fopen function (r, w, a, etc.)
+     * @param string            $filePath  Also accept a resource
+     * @param string            $delimiter CSV delimiter
+     * @param list<string>|null $headers   Leave null to read the headers from the file
+     * @param string            $mode      Same parameter as the mode in the fopen function (r, w, a, etc.)
      */
     public function __construct(
         protected $filePath,
diff --git a/src/Filesystem/CsvResource.php b/src/Filesystem/CsvResource.php
index 3c536dca..4fc24d2d 100644
--- a/src/Filesystem/CsvResource.php
+++ b/src/Filesystem/CsvResource.php
@@ -25,6 +25,9 @@ class CsvResource implements WritableStructuredFileInterface, SeekableFileInterf
 
     protected ?int $lineCount = null;
 
+    /**
+     * @var list<string>
+     */
     protected array $headers;
 
     protected bool $manualHeaders = false;
@@ -37,6 +40,9 @@ class CsvResource implements WritableStructuredFileInterface, SeekableFileInterf
 
     protected bool $seekCalled = false;
 
+    /**
+     * @param list<string>|null $headers
+     */
     public function __construct(
         mixed $resource,
         protected string $delimiter = ',',
@@ -110,6 +116,9 @@ public function getLineCount(): int
         return $this->lineCount;
     }
 
+    /**
+     * @return list<string>
+     */
     public function getHeaders(): array
     {
         return $this->headers;
@@ -146,6 +155,8 @@ public function isEndOfFile(): bool
 
     /**
      * Warning, this function will return exactly the same value as the fgetcsv() function.
+     *
+     * @return list<string|null>|false
      */
     public function readRaw(?int $length = null): array|false
     {
@@ -155,6 +166,9 @@ public function readRaw(?int $length = null): array|false
         return fgetcsv($this->handler, $length, $this->delimiter, $this->enclosure, $this->escape);
     }
 
+    /**
+     * @return array<string, string|null>|null
+     */
     public function readLine(?int $length = null): ?array
     {
         $filePosition = $this->seekCalled ? "at position {$this->tell()}" : "on line {$this->getLineNumber()}";
@@ -186,6 +200,8 @@ public function readLine(?int $length = null): ?array
 
     /**
      * Warning, this function will return exactly the same value as the fgetcsv() function.
+     *
+     * @param array<bool|float|int|string|null> $fields
      */
     public function writeRaw(array $fields): int|false
     {
@@ -195,6 +211,9 @@ public function writeRaw(array $fields): int|false
         return fputcsv($this->handler, $fields, $this->delimiter, $this->enclosure, $this->escape);
     }
 
+    /**
+     * @param array<string, mixed> $fields
+     */
     public function writeLine(array $fields): int
     {
         $count = \count($fields);
@@ -284,6 +303,11 @@ protected function assertOpened(): void
         }
     }
 
+    /**
+     * @param list<string>|null $headers
+     *
+     * @return list<string>
+     */
     protected function parseHeaders(?array $headers = null): array
     {
         // If headers are not passed in the constructor but file is readable, try to read headers from file
diff --git a/src/Filesystem/FileStreamInterface.php b/src/Filesystem/FileStreamInterface.php
index 65b5b819..e319df39 100644
--- a/src/Filesystem/FileStreamInterface.php
+++ b/src/Filesystem/FileStreamInterface.php
@@ -27,6 +27,9 @@ public function getLineNumber(): int;
 
     public function isEndOfFile(): bool;
 
+    /**
+     * @return array<mixed>|null
+     */
     public function readLine(?int $length = null): ?array;
 
     /**
diff --git a/src/Filesystem/JsonStreamFile.php b/src/Filesystem/JsonStreamFile.php
index 6642a399..1253943d 100644
--- a/src/Filesystem/JsonStreamFile.php
+++ b/src/Filesystem/JsonStreamFile.php
@@ -26,6 +26,10 @@ class JsonStreamFile implements FileStreamInterface, WritableFileInterface
 
     protected int $lineNumber = 1;
 
+    /**
+     * @param list<int>|null $splFileObjectFlags
+     * @param list<int>|null $jsonFlags
+     */
     public function __construct(
         string $filename,
         string $mode = 'rb',
@@ -86,6 +90,8 @@ public function isEndOfFile(): bool
     /**
      * Return an array containing current data and moving the file pointer.
      *
+     * @return array<mixed>|null
+     *
      * @throws \UnexpectedValueException if the line decodes to a scalar value
      */
     public function readLine(?int $length = null): ?array
@@ -109,6 +115,9 @@ public function readLine(?int $length = null): ?array
         return $data;
     }
 
+    /**
+     * @param array<mixed> $fields
+     */
     public function writeLine(array $fields): int
     {
         $this->file->fwrite(json_encode($fields, $this->jsonFlags).\PHP_EOL);
diff --git a/src/Filesystem/SplFile.php b/src/Filesystem/SplFile.php
index 14f38c40..a7f55ec8 100644
--- a/src/Filesystem/SplFile.php
+++ b/src/Filesystem/SplFile.php
@@ -24,6 +24,9 @@ class SplFile
 
     protected int $lineNumber = 1;
 
+    /**
+     * @param list<int>|null $splFileObjectFlags
+     */
     public function __construct(
         string $filename,
         string $mode = 'rb',
diff --git a/src/Filesystem/StructuredFileInterface.php b/src/Filesystem/StructuredFileInterface.php
index 15e7db2e..4da6be9a 100644
--- a/src/Filesystem/StructuredFileInterface.php
+++ b/src/Filesystem/StructuredFileInterface.php
@@ -18,6 +18,9 @@
  */
 interface StructuredFileInterface extends FileStreamInterface
 {
+    /**
+     * @return list<string>
+     */
     public function getHeaders(): array;
 
     public function getHeaderCount(): int;
diff --git a/src/Filesystem/WritableFileInterface.php b/src/Filesystem/WritableFileInterface.php
index a4a61376..6ce4474e 100644
--- a/src/Filesystem/WritableFileInterface.php
+++ b/src/Filesystem/WritableFileInterface.php
@@ -18,5 +18,8 @@
  */
 interface WritableFileInterface extends FileStreamInterface
 {
+    /**
+     * @param array<mixed> $fields
+     */
     public function writeLine(array $fields): int;
 }
diff --git a/src/Logger/AbstractProcessor.php b/src/Logger/AbstractProcessor.php
index 715167ab..fb7b1e62 100644
--- a/src/Logger/AbstractProcessor.php
+++ b/src/Logger/AbstractProcessor.php
@@ -47,6 +47,11 @@ public function __invoke(LogRecord $record): LogRecord
         return $record;
     }
 
+    /**
+     * @param array<string, mixed> $record
+     *
+     * @return array<string, mixed>
+     */
     protected function normalizeRecordData(array $record): array
     {
         $newRecord = [];
@@ -57,6 +62,9 @@ protected function normalizeRecordData(array $record): array
         return $newRecord;
     }
 
+    /**
+     * @param array<string, mixed> $record
+     */
     protected function addProcessInfoToRecord(array &$record): void
     {
         $processHistory = $this->processManager->getProcessHistory();
@@ -69,6 +77,9 @@ protected function addProcessInfoToRecord(array &$record): void
         $this->addToRecord($record, 'process_context', $processHistory->getContext());
     }
 
+    /**
+     * @param array<string, mixed> $record
+     */
     protected function addTaskInfoToRecord(array &$record): void
     {
         $taskConfiguration = $this->processManager->getTaskConfiguration();
@@ -89,6 +100,9 @@ protected function addTaskInfoToRecord(array &$record): void
         }
     }
 
+    /**
+     * @param array<string, mixed> $record
+     */
     protected function addToRecord(array &$record, string $name, mixed $data): void
     {
         $record[$name] = $data;
diff --git a/src/Manager/ProcessManager.php b/src/Manager/ProcessManager.php
index 231460be..188f6515 100644
--- a/src/Manager/ProcessManager.php
+++ b/src/Manager/ProcessManager.php
@@ -84,6 +84,8 @@ public function getTaskConfiguration(): ?TaskConfiguration
      * This method decorates the real execution to add event & error handling
      *
      * @see ProcessManager::doExecute
+     *
+     * @param array<string, mixed> $context
      */
     public function execute(string $processCode, mixed $input = null, array $context = []): mixed
     {
@@ -118,6 +120,8 @@ public function execute(string $processCode, mixed $input = null, array $context
 
     /**
      * Real process execution, with a given input and context.
+     *
+     * @param array<string, mixed> $context
      */
     protected function doExecute(string $processCode, mixed $input = null, array $context = []): mixed
     {
@@ -463,6 +467,9 @@ protected function finalize(TaskConfiguration $taskConfiguration): void
         }
     }
 
+    /**
+     * @param array<string, mixed> $context
+     */
     protected function initializeStates(
         ProcessConfiguration $processConfiguration,
         array $context = [],
diff --git a/src/Model/AbstractConfigurableTask.php b/src/Model/AbstractConfigurableTask.php
index 5228cec6..c4eb99ee 100644
--- a/src/Model/AbstractConfigurableTask.php
+++ b/src/Model/AbstractConfigurableTask.php
@@ -21,6 +21,9 @@
  */
 abstract class AbstractConfigurableTask implements InitializableTaskInterface, ResetInterface
 {
+    /**
+     * @var array<string, mixed>|null
+     */
     protected ?array $options = null;
 
     /**
@@ -36,6 +39,9 @@ public function reset(): void
         $this->options = null;
     }
 
+    /**
+     * @return array<string, mixed>|null
+     */
     protected function getOptions(ProcessState $state): ?array
     {
         if (null === $this->options) {
diff --git a/src/Model/ProcessHistory.php b/src/Model/ProcessHistory.php
index 1149c99b..de7c51e5 100644
--- a/src/Model/ProcessHistory.php
+++ b/src/Model/ProcessHistory.php
@@ -36,6 +36,9 @@ class ProcessHistory implements \Stringable
 
     protected string $state = self::STATE_STARTED;
 
+    /**
+     * @param array<string, mixed> $context
+     */
     public function __construct(
         ProcessConfiguration $processConfiguration,
         protected array $context = [],
@@ -64,6 +67,9 @@ public function getProcessCode(): string
         return $this->processCode;
     }
 
+    /**
+     * @return array<string, mixed>
+     */
     public function getContext(): array
     {
         return $this->context;
diff --git a/src/Model/ProcessState.php b/src/Model/ProcessState.php
index c9a5cef7..13ef03d1 100644
--- a/src/Model/ProcessState.php
+++ b/src/Model/ProcessState.php
@@ -51,16 +51,25 @@ class ProcessState
 
     protected ?\Throwable $exception = null;
 
+    /**
+     * @var array<int|string, mixed>
+     */
     protected array $errorContext = [];
 
     protected ?int $returnCode = null;
 
     protected bool $skipped;
 
+    /**
+     * @var array<string, mixed>|null
+     */
     protected ?array $context = null;
 
     protected ?ContextualOptionResolver $contextualOptionResolver = null;
 
+    /**
+     * @var array<string, mixed>|null
+     */
     protected ?array $contextualizedOptions = null;
 
     protected ?ProcessState $previousState = null;
@@ -191,11 +200,17 @@ public function setException(?\Throwable $exception = null): void
         $this->exception = $exception;
     }
 
+    /**
+     * @return array<int|string, mixed>
+     */
     public function getErrorContext(): array
     {
         return $this->errorContext;
     }
 
+    /**
+     * @param array<int|string, mixed> $errorContext
+     */
     public function setErrorContext(array $errorContext): void
     {
         $this->errorContext = $errorContext;
@@ -260,11 +275,17 @@ public function isResolved(): bool
         return self::STATUS_RESOLVED === $this->status;
     }
 
+    /**
+     * @return array<string, mixed>
+     */
     public function getContext(): array
     {
         return $this->context;
     }
 
+    /**
+     * @param array<string, mixed> $context
+     */
     public function setContext(array $context): void
     {
         if ($this->context) {
@@ -274,6 +295,9 @@ public function setContext(array $context): void
         $this->context = $context;
     }
 
+    /**
+     * @return array<string, mixed>|null
+     */
     public function getContextualizedOptions(): ?array
     {
         if (!$this->contextualizedOptions) {
diff --git a/src/Model/SubprocessInstance.php b/src/Model/SubprocessInstance.php
index ff49bc70..f52b94f0 100644
--- a/src/Model/SubprocessInstance.php
+++ b/src/Model/SubprocessInstance.php
@@ -27,6 +27,9 @@ class SubprocessInstance
 
     protected string $bufferPath;
 
+    /**
+     * @var array<string, mixed>
+     */
     protected array $options;
 
     protected string $consolePath;
@@ -35,6 +38,10 @@ class SubprocessInstance
 
     protected string $logDir;
 
+    /**
+     * @param array<string, mixed> $context
+     * @param array<string, mixed> $options
+     */
     public function __construct(
         KernelInterface $kernel,
         protected string $processCode,
@@ -125,11 +132,17 @@ public function getInput(): ?string
         return $this->input;
     }
 
+    /**
+     * @return array<string, mixed>
+     */
     public function getOptions(): array
     {
         return $this->options;
     }
 
+    /**
+     * @return array<string, mixed>
+     */
     public function getContext(): array
     {
         return $this->context;
diff --git a/src/Registry/ProcessConfigurationRegistry.php b/src/Registry/ProcessConfigurationRegistry.php
index 2c5c9fa4..d22feea6 100644
--- a/src/Registry/ProcessConfigurationRegistry.php
+++ b/src/Registry/ProcessConfigurationRegistry.php
@@ -29,6 +29,9 @@ class ProcessConfigurationRegistry
      */
     protected array $processConfigurations = [];
 
+    /**
+     * @param array<string, array<string, mixed>> $rawConfiguration
+     */
     public function __construct(
         protected array $rawConfiguration,
         protected string $defaultErrorStrategy,
diff --git a/src/Task/AbstractIterableOutputTask.php b/src/Task/AbstractIterableOutputTask.php
index e586f062..b756d049 100644
--- a/src/Task/AbstractIterableOutputTask.php
+++ b/src/Task/AbstractIterableOutputTask.php
@@ -76,12 +76,6 @@ protected function handleIteratorFromInput(ProcessState $state): void
             $this->iterator = null;
         }
 
-        // This should never be reached
-        /* @phpstan-ignore-next-line */
-        if (null !== $this->iterator) {
-            throw new \UnexpectedValueException("At this point iterator should have been null, maybe it's a wrong type...");
-        }
-
         $this->iterator = $this->initializeIterator($state);
     }
 
diff --git a/src/Task/AggregateIterableTask.php b/src/Task/AggregateIterableTask.php
index 893d2206..bc87bf34 100644
--- a/src/Task/AggregateIterableTask.php
+++ b/src/Task/AggregateIterableTask.php
@@ -23,6 +23,9 @@
  */
 class AggregateIterableTask implements BlockingTaskInterface
 {
+    /**
+     * @var list<mixed>
+     */
     protected array $result = [];
 
     public function execute(ProcessState $state): void
diff --git a/src/Task/ArrayMergeTask.php b/src/Task/ArrayMergeTask.php
index a00e45ae..93a2ebb5 100644
--- a/src/Task/ArrayMergeTask.php
+++ b/src/Task/ArrayMergeTask.php
@@ -25,6 +25,9 @@ class ArrayMergeTask extends AbstractConfigurableTask implements BlockingTaskInt
 {
     protected const MERGE_FUNC = ['array_merge', 'array_merge_recursive', 'array_replace', 'array_replace_recursive'];
 
+    /**
+     * @var array<mixed>
+     */
     protected array $mergedOutput = [];
 
     public function execute(ProcessState $state): void
diff --git a/src/Task/ColumnAggregatorTask.php b/src/Task/ColumnAggregatorTask.php
index 33f9445f..b3feaf21 100644
--- a/src/Task/ColumnAggregatorTask.php
+++ b/src/Task/ColumnAggregatorTask.php
@@ -29,6 +29,9 @@ class ColumnAggregatorTask extends AbstractConfigurableTask implements BlockingT
 {
     use ConditionTrait;
 
+    /**
+     * @var array<mixed>
+     */
     protected array $result = [];
 
     public function __construct(
diff --git a/src/Task/File/Csv/AbstractCsvResourceTask.php b/src/Task/File/Csv/AbstractCsvResourceTask.php
index a0ed37b9..a4c8be16 100644
--- a/src/Task/File/Csv/AbstractCsvResourceTask.php
+++ b/src/Task/File/Csv/AbstractCsvResourceTask.php
@@ -63,5 +63,10 @@ protected function configureOptions(OptionsResolver $resolver): void
         $resolver->setAllowedTypes('headers', ['null', 'array']);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     *
+     * @return list<string>|null
+     */
     abstract protected function getHeaders(ProcessState $state, array $options): ?array;
 }
diff --git a/src/Task/File/Csv/CsvReaderTask.php b/src/Task/File/Csv/CsvReaderTask.php
index f21d593c..635041f4 100644
--- a/src/Task/File/Csv/CsvReaderTask.php
+++ b/src/Task/File/Csv/CsvReaderTask.php
@@ -84,6 +84,11 @@ public function next(ProcessState $state): bool
         return !$endOfFile;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     *
+     * @return list<string>|null
+     */
     protected function getHeaders(ProcessState $state, array $options): ?array
     {
         return $options['headers'];
diff --git a/src/Task/File/Csv/CsvWriterTask.php b/src/Task/File/Csv/CsvWriterTask.php
index e87a0931..c0e1a922 100644
--- a/src/Task/File/Csv/CsvWriterTask.php
+++ b/src/Task/File/Csv/CsvWriterTask.php
@@ -67,6 +67,9 @@ protected function configureOptions(OptionsResolver $resolver): void
         );
     }
 
+    /**
+     * @return array<mixed>
+     */
     protected function getInput(ProcessState $state): array
     {
         $input = $state->getInput();
@@ -84,6 +87,11 @@ protected function getInput(ProcessState $state): array
         return $input;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     *
+     * @return list<string>|null
+     */
     protected function getHeaders(ProcessState $state, array $options): ?array
     {
         $headers = $options['headers'];
diff --git a/src/Task/File/Csv/InputCsvReaderTask.php b/src/Task/File/Csv/InputCsvReaderTask.php
index 2234a263..2781c000 100644
--- a/src/Task/File/Csv/InputCsvReaderTask.php
+++ b/src/Task/File/Csv/InputCsvReaderTask.php
@@ -21,6 +21,9 @@
  */
 class InputCsvReaderTask extends CsvReaderTask
 {
+    /**
+     * @return array<string, mixed>
+     */
     #[\Override]
     protected function getOptions(ProcessState $state): array
     {
@@ -45,6 +48,8 @@ protected function configureOptions(OptionsResolver $resolver): void
 
     /**
      * If there is no base_path, then the given path from input should be absolute.
+     *
+     * @param array<string, mixed> $options
      */
     protected function getFilePath(array $options, string $input): string
     {
diff --git a/src/Task/File/FolderBrowserTask.php b/src/Task/File/FolderBrowserTask.php
index 2148fe47..540e2c61 100644
--- a/src/Task/File/FolderBrowserTask.php
+++ b/src/Task/File/FolderBrowserTask.php
@@ -30,7 +30,7 @@
 class FolderBrowserTask extends AbstractConfigurableTask implements IterableTaskInterface
 {
     /**
-     * @var \Iterator|SplFileInfo[]|null
+     * @var \Iterator<string, SplFileInfo>|array<SplFileInfo>|null
      */
     protected \Iterator|array|null $files = null;
 
diff --git a/src/Task/File/InputFileReaderTask.php b/src/Task/File/InputFileReaderTask.php
index d378a6dd..b2b36178 100644
--- a/src/Task/File/InputFileReaderTask.php
+++ b/src/Task/File/InputFileReaderTask.php
@@ -21,6 +21,9 @@
  */
 class InputFileReaderTask extends FileReaderTask
 {
+    /**
+     * @return array<string, mixed>
+     */
     #[\Override]
     protected function getOptions(ProcessState $state): array
     {
diff --git a/src/Task/File/InputFolderBrowserTask.php b/src/Task/File/InputFolderBrowserTask.php
index 6a819f01..ae7a98d3 100644
--- a/src/Task/File/InputFolderBrowserTask.php
+++ b/src/Task/File/InputFolderBrowserTask.php
@@ -61,6 +61,9 @@ protected function configureOptions(OptionsResolver $resolver): void
         $resolver->setAllowedTypes('base_folder_path', ['string']);
     }
 
+    /**
+     * @return array<string, mixed>
+     */
     #[\Override]
     protected function getOptions(ProcessState $state): array
     {
diff --git a/src/Task/File/InputLineReaderTask.php b/src/Task/File/InputLineReaderTask.php
index 73ac0ea2..1737f404 100644
--- a/src/Task/File/InputLineReaderTask.php
+++ b/src/Task/File/InputLineReaderTask.php
@@ -21,6 +21,9 @@
  */
 class InputLineReaderTask extends LineReaderTask
 {
+    /**
+     * @return array<string, mixed>
+     */
     #[\Override]
     protected function getOptions(ProcessState $state): array
     {
diff --git a/src/Task/GroupByAggregateIterableTask.php b/src/Task/GroupByAggregateIterableTask.php
index b92e2f18..6891add0 100644
--- a/src/Task/GroupByAggregateIterableTask.php
+++ b/src/Task/GroupByAggregateIterableTask.php
@@ -30,6 +30,9 @@ class GroupByAggregateIterableTask extends AbstractConfigurableTask implements B
      */
     final public const GROUP_BY_OPTION = 'group_by_accessors';
 
+    /**
+     * @var array<mixed>
+     */
     protected array $result = [];
 
     public function __construct(
diff --git a/src/Task/InputAggregatorTask.php b/src/Task/InputAggregatorTask.php
index c5b68fa3..12af9859 100644
--- a/src/Task/InputAggregatorTask.php
+++ b/src/Task/InputAggregatorTask.php
@@ -26,6 +26,9 @@
  */
 class InputAggregatorTask extends AbstractConfigurableTask
 {
+    /**
+     * @var array<string, mixed>
+     */
     protected array $inputs = [];
 
     /**
@@ -35,7 +38,7 @@ class InputAggregatorTask extends AbstractConfigurableTask
     public function execute(ProcessState $state): void
     {
         $previousState = $state->getPreviousState();
-        if (!$previousState || !$previousState->getTaskConfiguration()) {
+        if (!$previousState instanceof ProcessState) {
             throw new \UnexpectedValueException('This task cannot be used without a previous task');
         }
 
diff --git a/src/Task/InputIteratorTask.php b/src/Task/InputIteratorTask.php
index a079626d..4af27f80 100644
--- a/src/Task/InputIteratorTask.php
+++ b/src/Task/InputIteratorTask.php
@@ -27,7 +27,16 @@ protected function initializeIterator(ProcessState $state): \Iterator
             return $input;
         }
         if ($input instanceof \IteratorAggregate) {
-            return $input->getIterator();
+            $iterator = $input->getIterator();
+            if ($iterator instanceof \Iterator) {
+                return $iterator;
+            }
+
+            // getIterator() may return any \Traversable, such as another \IteratorAggregate
+            $iterator = new \IteratorIterator($iterator);
+            $iterator->rewind();
+
+            return $iterator;
         }
         if (\is_array($input)) {
             return new \ArrayIterator($input);
diff --git a/src/Task/IterableBatchTask.php b/src/Task/IterableBatchTask.php
index f841f3f5..692e5666 100644
--- a/src/Task/IterableBatchTask.php
+++ b/src/Task/IterableBatchTask.php
@@ -26,6 +26,9 @@
  */
 class IterableBatchTask extends AbstractConfigurableTask implements FlushableTaskInterface, IterableTaskInterface
 {
+    /**
+     * @var \SplQueue<mixed>|null
+     */
     protected ?\SplQueue $outputQueue = null;
 
     protected bool $flushMode = false;
diff --git a/src/Task/Process/ProcessLauncherTask.php b/src/Task/Process/ProcessLauncherTask.php
index 5f5789b6..692016fa 100644
--- a/src/Task/Process/ProcessLauncherTask.php
+++ b/src/Task/Process/ProcessLauncherTask.php
@@ -35,6 +35,9 @@ class ProcessLauncherTask extends AbstractConfigurableTask implements FlushableT
      */
     protected array $launchedProcesses = [];
 
+    /**
+     * @var \SplQueue<string>
+     */
     protected \SplQueue $finishedBuffers;
 
     protected bool $flushMode = false;
@@ -59,7 +62,6 @@ public function execute(ProcessState $state): void
             $state->setOutput($this->finishedBuffers->dequeue());
 
             // After dequeue, stop flush
-            /* @phpstan-ignore-next-line */
             if ($this->finishedBuffers->isEmpty()) {
                 $this->flushMode = false;
             }
diff --git a/src/Task/RowAggregatorTask.php b/src/Task/RowAggregatorTask.php
index 7e5c85be..f999982f 100644
--- a/src/Task/RowAggregatorTask.php
+++ b/src/Task/RowAggregatorTask.php
@@ -27,6 +27,9 @@
  */
 class RowAggregatorTask extends AbstractConfigurableTask implements BlockingTaskInterface
 {
+    /**
+     * @var array<mixed>
+     */
     protected array $result = [];
 
     public function __construct(
diff --git a/src/Task/SimpleBatchTask.php b/src/Task/SimpleBatchTask.php
index 6bdb99bf..8f711c20 100644
--- a/src/Task/SimpleBatchTask.php
+++ b/src/Task/SimpleBatchTask.php
@@ -23,6 +23,9 @@
  */
 class SimpleBatchTask extends AbstractConfigurableTask implements FlushableTaskInterface
 {
+    /**
+     * @var list<mixed>
+     */
     protected array $elements = [];
 
     public function flush(ProcessState $state): void
diff --git a/src/Transformer/Array/ArrayElementTransformer.php b/src/Transformer/Array/ArrayElementTransformer.php
index 933e12a8..093e29d5 100644
--- a/src/Transformer/Array/ArrayElementTransformer.php
+++ b/src/Transformer/Array/ArrayElementTransformer.php
@@ -21,6 +21,9 @@
  */
 class ArrayElementTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         return array_values(\array_slice($value, $options['index'], 1))[0];
diff --git a/src/Transformer/Array/ArrayFilterTransformer.php b/src/Transformer/Array/ArrayFilterTransformer.php
index a755a985..198d3b1b 100644
--- a/src/Transformer/Array/ArrayFilterTransformer.php
+++ b/src/Transformer/Array/ArrayFilterTransformer.php
@@ -33,6 +33,8 @@ public function __construct(PropertyAccessorInterface $accessor)
     }
 
     /**
+     * @param array<string, mixed> $options
+     *
      * @return array<int|string, mixed>
      */
     public function transform(mixed $value, array $options = []): array
diff --git a/src/Transformer/Array/ArrayFirstTransformer.php b/src/Transformer/Array/ArrayFirstTransformer.php
index fef817e4..6a8a61fd 100644
--- a/src/Transformer/Array/ArrayFirstTransformer.php
+++ b/src/Transformer/Array/ArrayFirstTransformer.php
@@ -23,6 +23,8 @@ class ArrayFirstTransformer implements ConfigurableTransformerInterface
 {
     /**
      * Must return the transformed $value.
+     *
+     * @param array<string, mixed> $options
      */
     public function transform(mixed $value, array $options = []): mixed
     {
diff --git a/src/Transformer/Array/ArrayLastTransformer.php b/src/Transformer/Array/ArrayLastTransformer.php
index c2389852..6a3c477f 100644
--- a/src/Transformer/Array/ArrayLastTransformer.php
+++ b/src/Transformer/Array/ArrayLastTransformer.php
@@ -20,6 +20,9 @@
  */
 class ArrayLastTransformer implements TransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         return array_values(\array_slice($value, -1))[0];
diff --git a/src/Transformer/Array/ArrayMapTransformer.php b/src/Transformer/Array/ArrayMapTransformer.php
index 1263a9f7..e878021d 100644
--- a/src/Transformer/Array/ArrayMapTransformer.php
+++ b/src/Transformer/Array/ArrayMapTransformer.php
@@ -33,6 +33,10 @@ public function __construct(TransformerRegistry $transformerRegistry)
 
     /**
      * Must return the transformed $value.
+     *
+     * @param array<string, mixed> $options
+     *
+     * @return array<mixed>
      */
     public function transform(mixed $value, array $options = []): array
     {
diff --git a/src/Transformer/Array/ArrayUnsetTransformer.php b/src/Transformer/Array/ArrayUnsetTransformer.php
index 0e2bcf29..51d6b400 100644
--- a/src/Transformer/Array/ArrayUnsetTransformer.php
+++ b/src/Transformer/Array/ArrayUnsetTransformer.php
@@ -21,6 +21,9 @@
  */
 class ArrayUnsetTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         if (!\is_array($value)) {
diff --git a/src/Transformer/CachedTransformer.php b/src/Transformer/CachedTransformer.php
index 70e7bf46..9cb226e7 100644
--- a/src/Transformer/CachedTransformer.php
+++ b/src/Transformer/CachedTransformer.php
@@ -62,6 +62,9 @@ static function (Options $options, $value) {
         $this->configureTransformersOptions($resolver, 'key_transformers');
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         $cacheKey = $this->generateCacheKey($options['cache_key'], $value, $options);
@@ -104,6 +107,9 @@ public function getCode(): string
         return 'cached';
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     protected function generateCacheKey(string $cacheKeyRoot, mixed $value, array $options): bool|string
     {
         $value = $this->applyTransformers($options['key_transformers'], $value);
diff --git a/src/Transformer/CallbackTransformer.php b/src/Transformer/CallbackTransformer.php
index 88e1f275..a18e6ddd 100644
--- a/src/Transformer/CallbackTransformer.php
+++ b/src/Transformer/CallbackTransformer.php
@@ -24,6 +24,8 @@ class CallbackTransformer implements ConfigurableTransformerInterface
 {
     /**
      * Must return the transformed $value.
+     *
+     * @param array<string, mixed> $options
      */
     public function transform(mixed $value, array $options = []): mixed
     {
diff --git a/src/Transformer/CastTransformer.php b/src/Transformer/CastTransformer.php
index 559af464..7778ec04 100644
--- a/src/Transformer/CastTransformer.php
+++ b/src/Transformer/CastTransformer.php
@@ -20,6 +20,9 @@
  */
 class CastTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         settype($value, $options['type']);
diff --git a/src/Transformer/ConditionTrait.php b/src/Transformer/ConditionTrait.php
index 076cb0e3..9e282e8e 100644
--- a/src/Transformer/ConditionTrait.php
+++ b/src/Transformer/ConditionTrait.php
@@ -26,6 +26,8 @@ trait ConditionTrait
     /**
      * Test the input with the given set of conditions
      * True by default.
+     *
+     * @param array<string, mixed> $conditions
      */
     protected function checkCondition(mixed $input, array $conditions): bool
     {
diff --git a/src/Transformer/ConstantTransformer.php b/src/Transformer/ConstantTransformer.php
index ec0ae7ca..7f3c34d2 100644
--- a/src/Transformer/ConstantTransformer.php
+++ b/src/Transformer/ConstantTransformer.php
@@ -28,6 +28,8 @@ public function configureOptions(OptionsResolver $resolver): void
 
     /**
      * Must return the transformed $value.
+     *
+     * @param array<string, mixed> $options
      */
     public function transform(mixed $value, array $options = []): mixed
     {
diff --git a/src/Transformer/ConvertValueTransformer.php b/src/Transformer/ConvertValueTransformer.php
index e9a7775b..84579531 100644
--- a/src/Transformer/ConvertValueTransformer.php
+++ b/src/Transformer/ConvertValueTransformer.php
@@ -22,6 +22,8 @@ class ConvertValueTransformer implements ConfigurableTransformerInterface
 {
     /**
      * Must return the transformed $value.
+     *
+     * @param array<string, mixed> $options
      */
     public function transform(mixed $value, array $options = []): mixed
     {
diff --git a/src/Transformer/Date/DateFormatTransformer.php b/src/Transformer/Date/DateFormatTransformer.php
index ba95e3d0..bdd5cecc 100644
--- a/src/Transformer/Date/DateFormatTransformer.php
+++ b/src/Transformer/Date/DateFormatTransformer.php
@@ -26,6 +26,9 @@
  */
 class DateFormatTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         if (!$value) {
diff --git a/src/Transformer/Date/DateParserTransformer.php b/src/Transformer/Date/DateParserTransformer.php
index 526d0afd..cb5ade3f 100644
--- a/src/Transformer/Date/DateParserTransformer.php
+++ b/src/Transformer/Date/DateParserTransformer.php
@@ -26,6 +26,9 @@
  */
 class DateParserTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         if (!$value || $value instanceof \DateTime) {
diff --git a/src/Transformer/DebugTransformer.php b/src/Transformer/DebugTransformer.php
index 16f11174..2d528b09 100644
--- a/src/Transformer/DebugTransformer.php
+++ b/src/Transformer/DebugTransformer.php
@@ -20,6 +20,9 @@
  */
 class DebugTransformer implements TransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         if (class_exists(VarDumper::class)) {
diff --git a/src/Transformer/DefaultTransformer.php b/src/Transformer/DefaultTransformer.php
index 83628fe9..f83effd0 100644
--- a/src/Transformer/DefaultTransformer.php
+++ b/src/Transformer/DefaultTransformer.php
@@ -25,6 +25,9 @@ public function configureOptions(OptionsResolver $resolver): void
         $resolver->setRequired('value');
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         if (!$value) {
diff --git a/src/Transformer/EvaluatorTransformer.php b/src/Transformer/EvaluatorTransformer.php
index 33ceba2b..a0ecdeb4 100644
--- a/src/Transformer/EvaluatorTransformer.php
+++ b/src/Transformer/EvaluatorTransformer.php
@@ -47,6 +47,9 @@ function (Options $options, $expression) {
         );
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         return $this->language->evaluate($options['expression'], $value);
diff --git a/src/Transformer/ExpressionLanguageMapTransformer.php b/src/Transformer/ExpressionLanguageMapTransformer.php
index 186231e7..5ea27bff 100644
--- a/src/Transformer/ExpressionLanguageMapTransformer.php
+++ b/src/Transformer/ExpressionLanguageMapTransformer.php
@@ -64,6 +64,9 @@ function (Options $options, $values): array {
         );
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         $input = [
diff --git a/src/Transformer/GenericTransformer.php b/src/Transformer/GenericTransformer.php
index bf53d955..11e4d29a 100644
--- a/src/Transformer/GenericTransformer.php
+++ b/src/Transformer/GenericTransformer.php
@@ -27,8 +27,14 @@ class GenericTransformer implements ConfigurableTransformerInterface
 
     protected ?string $transformerCode = null;
 
+    /**
+     * @var array<string, mixed>|null
+     */
     protected ?array $preconfiguredTransformerOptions = null;
 
+    /**
+     * @var array<string, mixed>|null
+     */
     protected ?array $contextualOptions = null;
 
     public function __construct(
@@ -40,6 +46,8 @@ public function __construct(
 
     /**
      * Register the generic options, and load the transformer list.
+     *
+     * @param array<string, mixed> $options
      */
     public function initialize(string $code, array $options = []): void
     {
@@ -102,6 +110,9 @@ public function configureOptions(OptionsResolver $resolver): void
         });
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         return $this->applyTransformers($options['transformers'], $value);
@@ -114,6 +125,11 @@ public function getCode(): string
 
     /**
      * Get the real transformer from contextual options + generic definitions.
+     *
+     * @param Options<array<string, mixed>> $options
+     * @param array<string, mixed>          $transformerOptions
+     *
+     * @return array<string, mixed>
      */
     public function normalizeTransformerOptions(Options $options, array $transformerOptions): array
     {
diff --git a/src/Transformer/MappingTransformer.php b/src/Transformer/MappingTransformer.php
index ff8b0001..2668c403 100644
--- a/src/Transformer/MappingTransformer.php
+++ b/src/Transformer/MappingTransformer.php
@@ -37,6 +37,9 @@ public function __construct(
         $this->transformerRegistry = $transformerRegistry;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         if (!empty($options['initial_value']) && $options['keep_input']) {
@@ -142,7 +145,7 @@ function (Options $options, $value): array {
                 $resolvedMapping = [];
                 $mappingResolver = new OptionsResolver();
                 $this->configureMappingOptions($mappingResolver);
-                /** @var array $value */
+                /** @var array<string, array<string, mixed>|null> $value */
                 foreach ($value as $property => $mappingConfig) {
                     $resolvedMapping[$property] = $mappingResolver->resolve($mappingConfig ?? []);
                 }
diff --git a/src/Transformer/MultiReplaceTransformer.php b/src/Transformer/MultiReplaceTransformer.php
index 5ff4b927..849baf12 100644
--- a/src/Transformer/MultiReplaceTransformer.php
+++ b/src/Transformer/MultiReplaceTransformer.php
@@ -24,6 +24,9 @@
  */
 class MultiReplaceTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         foreach ($options['replace_mapping'] as $pattern => $replacement) {
diff --git a/src/Transformer/Object/InstantiateTransformer.php b/src/Transformer/Object/InstantiateTransformer.php
index 41993a58..902ce037 100644
--- a/src/Transformer/Object/InstantiateTransformer.php
+++ b/src/Transformer/Object/InstantiateTransformer.php
@@ -21,6 +21,9 @@
  */
 class InstantiateTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         if (!\is_array($value)) {
diff --git a/src/Transformer/Object/PropertyAccessorTransformer.php b/src/Transformer/Object/PropertyAccessorTransformer.php
index 90e59b29..84497815 100644
--- a/src/Transformer/Object/PropertyAccessorTransformer.php
+++ b/src/Transformer/Object/PropertyAccessorTransformer.php
@@ -27,6 +27,9 @@ public function __construct(
     ) {
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         if (null === $value && $options['ignore_null']) {
diff --git a/src/Transformer/Object/RecursivePropertySetterTransformer.php b/src/Transformer/Object/RecursivePropertySetterTransformer.php
index 9bf7c0d4..4a924666 100644
--- a/src/Transformer/Object/RecursivePropertySetterTransformer.php
+++ b/src/Transformer/Object/RecursivePropertySetterTransformer.php
@@ -30,6 +30,9 @@ public function __construct(
     ) {
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         if (null === $value && $options['ignore_null']) {
diff --git a/src/Transformer/PregFilterTransformer.php b/src/Transformer/PregFilterTransformer.php
index 7b046878..9aa3aabf 100644
--- a/src/Transformer/PregFilterTransformer.php
+++ b/src/Transformer/PregFilterTransformer.php
@@ -19,6 +19,11 @@
 
 class PregFilterTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     *
+     * @return array<mixed>|string|null
+     */
     public function transform(mixed $value, array $options = []): array|string|null
     {
         $pattern = $options['pattern'];
diff --git a/src/Transformer/RulesTransformer.php b/src/Transformer/RulesTransformer.php
index c9e5fbbd..048d4c66 100644
--- a/src/Transformer/RulesTransformer.php
+++ b/src/Transformer/RulesTransformer.php
@@ -33,6 +33,9 @@ public function __construct(
         $this->transformerRegistry = $transformerRegistry;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         foreach ($options['rules_set'] as $rule) {
@@ -92,6 +95,8 @@ public function configureOptions(OptionsResolver $resolver): void
 
     /**
      * Configure options for one "rule" block.
+     *
+     * @param array<string, mixed>|null $expressionVariables
      */
     public function configureRuleOptions(OptionsResolver $resolver, ?array $expressionVariables = null): void
     {
@@ -127,6 +132,8 @@ public function configureRuleOptions(OptionsResolver $resolver, ?array $expressi
 
     /**
      * Test if a value match a rule.
+     *
+     * @param array<string, mixed> $rule
      */
     protected function matchRule(mixed $value, array $rule, bool $useValueAsVariable): bool
     {
diff --git a/src/Transformer/Serialization/DenormalizeTransformer.php b/src/Transformer/Serialization/DenormalizeTransformer.php
index f939b074..3e6526a6 100644
--- a/src/Transformer/Serialization/DenormalizeTransformer.php
+++ b/src/Transformer/Serialization/DenormalizeTransformer.php
@@ -39,6 +39,9 @@ public function configureOptions(OptionsResolver $resolver): void
         $resolver->setAllowedTypes('context', ['array']);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         return $this->denormalizer->denormalize($value, $options['class'], $options['format'], $options['context']);
diff --git a/src/Transformer/Serialization/NormalizeTransformer.php b/src/Transformer/Serialization/NormalizeTransformer.php
index f23293a6..b71e038e 100644
--- a/src/Transformer/Serialization/NormalizeTransformer.php
+++ b/src/Transformer/Serialization/NormalizeTransformer.php
@@ -37,6 +37,9 @@ public function configureOptions(OptionsResolver $resolver): void
         $resolver->setAllowedTypes('context', ['array']);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         return $this->normalizer->normalize($value, $options['format'], $options['context']);
diff --git a/src/Transformer/String/ExplodeTransformer.php b/src/Transformer/String/ExplodeTransformer.php
index 32542a43..fd2e4be6 100644
--- a/src/Transformer/String/ExplodeTransformer.php
+++ b/src/Transformer/String/ExplodeTransformer.php
@@ -21,6 +21,11 @@
  */
 class ExplodeTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     *
+     * @return list<string>
+     */
     public function transform(mixed $value, array $options = []): array
     {
         if (null === $value || '' === $value) {
diff --git a/src/Transformer/String/HashTransformer.php b/src/Transformer/String/HashTransformer.php
index 2dc58b11..b8422a41 100644
--- a/src/Transformer/String/HashTransformer.php
+++ b/src/Transformer/String/HashTransformer.php
@@ -32,6 +32,9 @@ public function configureOptions(OptionsResolver $resolver): void
         $resolver->setAllowedTypes('raw_output', 'bool');
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): string
     {
         return hash((string) $options['algo'], (string) $value, $options['raw_output']);
diff --git a/src/Transformer/String/ImplodeTransformer.php b/src/Transformer/String/ImplodeTransformer.php
index 7257ac13..d60e7ac0 100644
--- a/src/Transformer/String/ImplodeTransformer.php
+++ b/src/Transformer/String/ImplodeTransformer.php
@@ -27,6 +27,9 @@ public function configureOptions(OptionsResolver $resolver): void
         $resolver->setAllowedTypes('separator', 'string');
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): string
     {
         if (!\is_array($value)) {
diff --git a/src/Transformer/String/PregMatchTransformer.php b/src/Transformer/String/PregMatchTransformer.php
index 143ba36b..38899f0e 100644
--- a/src/Transformer/String/PregMatchTransformer.php
+++ b/src/Transformer/String/PregMatchTransformer.php
@@ -21,6 +21,11 @@
  */
 class PregMatchTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     *
+     * @return array<mixed>|null
+     */
     public function transform(mixed $value, array $options = []): ?array
     {
         if (null === $value || '' === $value) {
diff --git a/src/Transformer/String/SlugifyTransformer.php b/src/Transformer/String/SlugifyTransformer.php
index 7b682905..f3c02275 100644
--- a/src/Transformer/String/SlugifyTransformer.php
+++ b/src/Transformer/String/SlugifyTransformer.php
@@ -23,6 +23,9 @@
  */
 class SlugifyTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): string
     {
         /** @var \Transliterator $transliterator */
diff --git a/src/Transformer/String/SprintfTransformer.php b/src/Transformer/String/SprintfTransformer.php
index a3263615..e87804ee 100644
--- a/src/Transformer/String/SprintfTransformer.php
+++ b/src/Transformer/String/SprintfTransformer.php
@@ -21,6 +21,9 @@
  */
 class SprintfTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): string
     {
         if (!\is_array($value)) {
diff --git a/src/Transformer/String/TrimTransformer.php b/src/Transformer/String/TrimTransformer.php
index e2d97819..ad305cf9 100644
--- a/src/Transformer/String/TrimTransformer.php
+++ b/src/Transformer/String/TrimTransformer.php
@@ -21,6 +21,9 @@
  */
 class TrimTransformer implements ConfigurableTransformerInterface
 {
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, ?array $options = []): ?string
     {
         if (null === $options || [] === $options) {
diff --git a/src/Transformer/TransformerInterface.php b/src/Transformer/TransformerInterface.php
index 7cf44d54..8a61e7fe 100644
--- a/src/Transformer/TransformerInterface.php
+++ b/src/Transformer/TransformerInterface.php
@@ -20,6 +20,8 @@ interface TransformerInterface
 {
     /**
      * Must return the transformed $value.
+     *
+     * @param array<string, mixed> $options
      */
     public function transform(mixed $value, array $options = []): mixed;
 
diff --git a/src/Transformer/TransformerTrait.php b/src/Transformer/TransformerTrait.php
index e43563e6..34b0a2d8 100644
--- a/src/Transformer/TransformerTrait.php
+++ b/src/Transformer/TransformerTrait.php
@@ -25,6 +25,11 @@ trait TransformerTrait
 
     /**
      * Transform the list of transformer codes + options into a list of Closure (better performances).
+     *
+     * @param Options<array<string, mixed>>            $options
+     * @param array<string, array<string, mixed>|null> $transformers
+     *
+     * @return array<string, \Closure>
      */
     public function normalizeTransformers(Options $options, array $transformers): array
     {
@@ -49,6 +54,9 @@ public function normalizeTransformers(Options $options, array $transformers): ar
         return $transformerClosures;
     }
 
+    /**
+     * @param array<string, \Closure> $transformers
+     */
     protected function applyTransformers(array $transformers, mixed $value): mixed
     {
         // Quick return for better perfs
@@ -104,6 +112,8 @@ protected function configureTransformersOptions(
 
     /**
      * Check the options to always return an array, or fail on unexpected values.
+     *
+     * @return array<string, mixed>
      */
     private function checkTransformerOptions(mixed $transformerOptions, string $transformerCode): array
     {
diff --git a/src/Transformer/TypeSetterTransformer.php b/src/Transformer/TypeSetterTransformer.php
index 606c62ff..35133e02 100644
--- a/src/Transformer/TypeSetterTransformer.php
+++ b/src/Transformer/TypeSetterTransformer.php
@@ -27,6 +27,9 @@ public function configureOptions(OptionsResolver $resolver): void
         $resolver->setAllowedTypes('type', 'string');
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         settype($value, $options['type']);
diff --git a/src/Transformer/UnsetTransformer.php b/src/Transformer/UnsetTransformer.php
index 112f4ad0..5b6caf76 100644
--- a/src/Transformer/UnsetTransformer.php
+++ b/src/Transformer/UnsetTransformer.php
@@ -28,6 +28,11 @@ public function __construct(PropertyAccessorInterface $accessor)
         $this->accessor = $accessor;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     *
+     * @return array<mixed>
+     */
     public function transform(mixed $value, array $options = []): array
     {
         if (!\is_array($value)) {
diff --git a/src/Transformer/WrapperTransformer.php b/src/Transformer/WrapperTransformer.php
index 297e7253..a3cd0b8d 100644
--- a/src/Transformer/WrapperTransformer.php
+++ b/src/Transformer/WrapperTransformer.php
@@ -19,6 +19,10 @@ class WrapperTransformer implements ConfigurableTransformerInterface
 {
     /**
      * Must return the transformed $value.
+     *
+     * @param array<string, mixed> $options
+     *
+     * @return array<mixed>
      */
     public function transform(mixed $value, array $options = []): array
     {
diff --git a/src/Transformer/Xml/XpathEvaluatorTransformer.php b/src/Transformer/Xml/XpathEvaluatorTransformer.php
index 32c650c4..87be9f8d 100644
--- a/src/Transformer/Xml/XpathEvaluatorTransformer.php
+++ b/src/Transformer/Xml/XpathEvaluatorTransformer.php
@@ -64,6 +64,8 @@ public function configureOptions(OptionsResolver $resolver): void
     /**
      * Configure options about how to handle xpath query results.
      * Available at root and subquery level.
+     *
+     * @param Options<array<string, mixed>>|null $parentOptions
      */
     public function configureQueryOptions(OptionsResolver $resolver, ?Options $parentOptions = null): void
     {
@@ -77,6 +79,9 @@ public function configureQueryOptions(OptionsResolver $resolver, ?Options $paren
         $resolver->setAllowedTypes('unwrap_value', 'bool');
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function transform(mixed $value, array $options = []): mixed
     {
         if (!$value instanceof \DOMNode) {
@@ -108,6 +113,9 @@ public function buildXpath(\DOMNode $node): \DOMXPath
         return new \DOMXPath($doc);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     public function query(\DOMXPath $xpath, string $query, \DOMNode $node, array $options): mixed
     {
         $nodeList = $xpath->query($query, $node);
diff --git a/src/Validator/ConstraintLoader.php b/src/Validator/ConstraintLoader.php
index e2adab9b..b71c32ed 100644
--- a/src/Validator/ConstraintLoader.php
+++ b/src/Validator/ConstraintLoader.php
@@ -27,6 +27,10 @@ public function loadClassMetadata(ClassMetadata $metadata): bool
      * Build constraints from textual data.
      *
      * @see \Symfony\Component\Validator\Mapping\Loader\YamlFileLoader::parseNodes
+     *
+     * @param array<mixed> $nodes
+     *
+     * @return array<mixed>
      */
     public function buildConstraints(array $nodes): array
     {
diff --git a/tests/Task/AbstractIterableOutputTaskTest.php b/tests/Task/AbstractIterableOutputTaskTest.php
index 583d217d..83be8110 100644
--- a/tests/Task/AbstractIterableOutputTaskTest.php
+++ b/tests/Task/AbstractIterableOutputTaskTest.php
@@ -102,6 +102,9 @@ public function testSplitJoinLineWithoutSplitColumnIsSkipped(): void
         self::assertSame([], $state->getErrorContext());
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options, mixed $input = null): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/ArrayMergeTaskTest.php b/tests/Task/ArrayMergeTaskTest.php
index e1f251c9..ba54191e 100644
--- a/tests/Task/ArrayMergeTaskTest.php
+++ b/tests/Task/ArrayMergeTaskTest.php
@@ -67,7 +67,9 @@ public static function mergeProvider(): iterable
     }
 
     /**
-     * @param list<array<mixed>> $inputs
+     * @param array<string, mixed> $options
+     * @param list<array<mixed>>   $inputs
+     * @param array<mixed>         $expected
      */
     #[DataProvider('mergeProvider')]
     public function testInputsAreMergedWithMergeFunction(array $options, array $inputs, array $expected): void
@@ -140,6 +142,9 @@ public function testInvalidMergeFunctionIsRejected(mixed $mergeFunction): void
         $task->initialize($state);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/ColumnAggregatorTaskTest.php b/tests/Task/ColumnAggregatorTaskTest.php
index cbbb03de..897d86bb 100644
--- a/tests/Task/ColumnAggregatorTaskTest.php
+++ b/tests/Task/ColumnAggregatorTaskTest.php
@@ -67,6 +67,8 @@ public function testMissingColumnThrows(): void
 
     /**
      * @param list<array<string, mixed>> $inputs
+     * @param array<string, mixed>       $options
+     * @param array<string, mixed>       $extraOptions
      */
     private function aggregate(array $options, array $inputs, array $extraOptions = []): mixed
     {
@@ -86,6 +88,9 @@ private function aggregate(array $options, array $inputs, array $extraOptions =
         return $state->getOutput();
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(string $class, array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/ConstantIterableOutputTaskTest.php b/tests/Task/ConstantIterableOutputTaskTest.php
index 04697d9a..9d4ee45d 100644
--- a/tests/Task/ConstantIterableOutputTaskTest.php
+++ b/tests/Task/ConstantIterableOutputTaskTest.php
@@ -130,6 +130,9 @@ private function iterate(ConstantIterableOutputTask $task, ProcessState $state):
         return $outputs;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options, mixed $input = null): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/ConstantOutputTaskTest.php b/tests/Task/ConstantOutputTaskTest.php
index 4b29355d..4fa809e7 100644
--- a/tests/Task/ConstantOutputTaskTest.php
+++ b/tests/Task/ConstantOutputTaskTest.php
@@ -92,6 +92,10 @@ public function testMissingOutputOptionFailsAtInitialization(): void
         $task->initialize($state);
     }
 
+    /**
+     * @param array<string, mixed> $context
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options, mixed $input = null, array $context = []): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/Event/EventDispatcherTaskTest.php b/tests/Task/Event/EventDispatcherTaskTest.php
index f0882f84..f72ee729 100644
--- a/tests/Task/Event/EventDispatcherTaskTest.php
+++ b/tests/Task/Event/EventDispatcherTaskTest.php
@@ -110,6 +110,9 @@ private function createDispatcher(array $eventNames): EventDispatcher
         return $dispatcher;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function execute(EventDispatcher $dispatcher, array $options, mixed $input = null): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/Csv/CsvReaderTaskTest.php b/tests/Task/File/Csv/CsvReaderTaskTest.php
index b1bb5a42..b1a612fa 100644
--- a/tests/Task/File/Csv/CsvReaderTaskTest.php
+++ b/tests/Task/File/Csv/CsvReaderTaskTest.php
@@ -117,6 +117,9 @@ private function iterate(CsvReaderTask $task, ProcessState $state, mixed $input
         return $outputs;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/Csv/CsvWriterTaskTest.php b/tests/Task/File/Csv/CsvWriterTaskTest.php
index 2059c265..11d02383 100644
--- a/tests/Task/File/Csv/CsvWriterTaskTest.php
+++ b/tests/Task/File/Csv/CsvWriterTaskTest.php
@@ -272,6 +272,9 @@ private function write(CsvWriterTask $task, ProcessState $state, array $inputs):
         $task->finalize($state);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/FileMoverTaskTest.php b/tests/Task/File/FileMoverTaskTest.php
index 11e53e18..759e3df2 100644
--- a/tests/Task/File/FileMoverTaskTest.php
+++ b/tests/Task/File/FileMoverTaskTest.php
@@ -198,6 +198,9 @@ public function testThrowsOnInvalidOptions(array $options): void
         $this->execute($options, $this->tmpDir.'/src/file.csv');
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function execute(array $options, mixed $input): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/FileReaderTaskTest.php b/tests/Task/File/FileReaderTaskTest.php
index fc85b339..c9601222 100644
--- a/tests/Task/File/FileReaderTaskTest.php
+++ b/tests/Task/File/FileReaderTaskTest.php
@@ -109,6 +109,9 @@ public function testThrowsOnInvalidFilenameOptionType(): void
         $this->execute(['filename' => 42]);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function execute(array $options, mixed $input = null): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/FileWriterTaskTest.php b/tests/Task/File/FileWriterTaskTest.php
index 7d22ecc7..f3cd312a 100644
--- a/tests/Task/File/FileWriterTaskTest.php
+++ b/tests/Task/File/FileWriterTaskTest.php
@@ -112,6 +112,9 @@ private function write(FileWriterTask $task, ProcessState $state, mixed $input):
         $task->execute($state);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/FolderBrowserTaskTest.php b/tests/Task/File/FolderBrowserTaskTest.php
index fc839f15..0c3cee5a 100644
--- a/tests/Task/File/FolderBrowserTaskTest.php
+++ b/tests/Task/File/FolderBrowserTaskTest.php
@@ -129,6 +129,9 @@ private function iterate(FolderBrowserTask $task, ProcessState $state, mixed $in
         return $outputs;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/InputFileReaderTaskTest.php b/tests/Task/File/InputFileReaderTaskTest.php
index bb4b8600..96551daf 100644
--- a/tests/Task/File/InputFileReaderTaskTest.php
+++ b/tests/Task/File/InputFileReaderTaskTest.php
@@ -125,6 +125,9 @@ private function read(InputFileReaderTask $task, ProcessState $state, mixed $inp
         return $state->getOutput();
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/JsonStream/JsonStreamReaderTaskTest.php b/tests/Task/File/JsonStream/JsonStreamReaderTaskTest.php
index 7ee3658d..c1660510 100644
--- a/tests/Task/File/JsonStream/JsonStreamReaderTaskTest.php
+++ b/tests/Task/File/JsonStream/JsonStreamReaderTaskTest.php
@@ -239,6 +239,9 @@ private function createFile(string $content, string $name = 'data.jsonl'): strin
         return $path;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/LineReaderTaskTest.php b/tests/Task/File/LineReaderTaskTest.php
index df1f0752..d84de8a0 100644
--- a/tests/Task/File/LineReaderTaskTest.php
+++ b/tests/Task/File/LineReaderTaskTest.php
@@ -100,6 +100,9 @@ private function iterate(LineReaderTask $task, ProcessState $state, mixed $input
         return $outputs;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/Xml/XmlReaderTaskTest.php b/tests/Task/File/Xml/XmlReaderTaskTest.php
index ca6689a6..51bc77a3 100644
--- a/tests/Task/File/Xml/XmlReaderTaskTest.php
+++ b/tests/Task/File/Xml/XmlReaderTaskTest.php
@@ -147,6 +147,9 @@ public function testModeMustBeAString(): void
         $this->execute(['file_path' => $this->tmpDir.'/file.xml', 'mode' => true]);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function execute(array $options, mixed $input = null): ProcessState
     {
         $task = $this->createTask();
@@ -174,6 +177,9 @@ public function log($level, string|\Stringable $message, array $context = []): v
         });
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/Xml/XmlWriterTaskTest.php b/tests/Task/File/Xml/XmlWriterTaskTest.php
index d91f3212..218c7bed 100644
--- a/tests/Task/File/Xml/XmlWriterTaskTest.php
+++ b/tests/Task/File/Xml/XmlWriterTaskTest.php
@@ -166,6 +166,9 @@ private function createDocument(string $xml): \DOMDocument
         return $dom;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/Yaml/YamlReaderTaskTest.php b/tests/Task/File/Yaml/YamlReaderTaskTest.php
index 52a509e1..f3e5627b 100644
--- a/tests/Task/File/Yaml/YamlReaderTaskTest.php
+++ b/tests/Task/File/Yaml/YamlReaderTaskTest.php
@@ -207,6 +207,9 @@ private function iterate(YamlReaderTask $task, ProcessState $state, mixed $input
         return [$outputs, $keys];
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/File/Yaml/YamlWriterTaskTest.php b/tests/Task/File/Yaml/YamlWriterTaskTest.php
index 3f2ea99c..951dc001 100644
--- a/tests/Task/File/Yaml/YamlWriterTaskTest.php
+++ b/tests/Task/File/Yaml/YamlWriterTaskTest.php
@@ -135,6 +135,9 @@ public function testInvalidOptionsThrow(array $options): void
         (new YamlWriterTask())->initialize($this->createState($options));
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function execute(array $options, mixed $input): ProcessState
     {
         $task = new YamlWriterTask();
@@ -146,6 +149,9 @@ private function execute(array $options, mixed $input): ProcessState
         return $state;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/FilterTaskTest.php b/tests/Task/FilterTaskTest.php
index 63d20541..761df166 100644
--- a/tests/Task/FilterTaskTest.php
+++ b/tests/Task/FilterTaskTest.php
@@ -74,7 +74,8 @@ public static function filterProvider(): iterable
     }
 
     /**
-     * @param list<int> $expectedKept
+     * @param array<string, mixed> $options
+     * @param list<int>            $expectedKept
      */
     #[DataProvider('filterProvider')]
     public function testInputsAreFiltered(array $options, array $expectedKept): void
@@ -138,6 +139,9 @@ public static function scalarProvider(): iterable
         yield 'other path on scalar is empty' => [['not_empty' => ['[key]' => null]], 'foo', true];
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     #[DataProvider('scalarProvider')]
     public function testScalarInput(array $options, mixed $input, bool $expectedSkipped): void
     {
@@ -156,6 +160,9 @@ public function testUnknownConditionIsRejected(): void
         $this->execute(['equals' => []], []);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function execute(array $options, mixed $input): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/GroupByAggregateIterableTaskTest.php b/tests/Task/GroupByAggregateIterableTaskTest.php
index 518d2292..166d5a17 100644
--- a/tests/Task/GroupByAggregateIterableTaskTest.php
+++ b/tests/Task/GroupByAggregateIterableTaskTest.php
@@ -130,6 +130,9 @@ private function createTask(mixed $groupBy): array
         return [$task, $state];
     }
 
+    /**
+     * @param list<mixed> $inputs
+     */
     private function aggregate(GroupByAggregateIterableTask $task, ProcessState $state, array $inputs): mixed
     {
         foreach ($inputs as $input) {
diff --git a/tests/Task/InputAggregatorTaskTest.php b/tests/Task/InputAggregatorTaskTest.php
index 4ef28066..b5a39b40 100644
--- a/tests/Task/InputAggregatorTaskTest.php
+++ b/tests/Task/InputAggregatorTaskTest.php
@@ -161,6 +161,9 @@ public static function invalidOptionsProvider(): iterable
         yield 'keep_inputs not an array' => [['input_codes' => [], 'keep_inputs' => 'a']];
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     #[DataProvider('invalidOptionsProvider')]
     public function testInvalidOptionsAreRejected(array $options): void
     {
@@ -171,6 +174,9 @@ public function testInvalidOptionsAreRejected(array $options): void
         $task->initialize($this->createState($options));
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function receive(InputAggregatorTask $task, array $options, string $previousTaskCode, mixed $input): ProcessState
     {
         $previousState = $this->createState([], $previousTaskCode);
@@ -184,6 +190,9 @@ private function receive(InputAggregatorTask $task, array $options, string $prev
         return $state;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options, string $code = 'aggregate'): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/InputIteratorTaskTest.php b/tests/Task/InputIteratorTaskTest.php
index e6af3bf2..b6b4750e 100644
--- a/tests/Task/InputIteratorTaskTest.php
+++ b/tests/Task/InputIteratorTaskTest.php
@@ -43,6 +43,23 @@ public static function iterableInputProvider(): iterable
         yield 'associative array' => [['a' => 1, 'b' => 2, 'c' => 3]];
         yield 'iterator' => [new \ArrayIterator(['a' => 1, 'b' => 2, 'c' => 3])];
         yield 'iterator aggregate' => [new \ArrayObject([1, 2, 3])];
+        yield 'generator aggregate' => [
+            new class implements \IteratorAggregate {
+                public function getIterator(): \Generator
+                {
+                    yield from [1, 2, 3];
+                }
+            },
+        ];
+        // getIterator() may return any \Traversable, such as another \IteratorAggregate
+        yield 'nested iterator aggregate' => [
+            new class implements \IteratorAggregate {
+                public function getIterator(): \Traversable
+                {
+                    return new \ArrayObject([1, 2, 3]);
+                }
+            },
+        ];
     }
 
     #[DataProvider('iterableInputProvider')]
@@ -114,6 +131,9 @@ public function testNonIterableInputThrows(mixed $input): void
         $task->execute($state);
     }
 
+    /**
+     * @return list<mixed>
+     */
     private function iterate(InputIteratorTask $task, ProcessState $state, mixed $input): array
     {
         $outputs = [];
diff --git a/tests/Task/IterableBatchTaskTest.php b/tests/Task/IterableBatchTaskTest.php
index debf563e..8010d97b 100644
--- a/tests/Task/IterableBatchTaskTest.php
+++ b/tests/Task/IterableBatchTaskTest.php
@@ -53,6 +53,8 @@ public function testNullBatchCountOnlyOutputsOnFlush(): void
     }
 
     /**
+     * @param array<string, mixed> $options
+     *
      * @return array{IterableBatchTask, ProcessState}
      */
     private function createTask(array $options): array
@@ -99,6 +101,9 @@ private function flush(IterableBatchTask $task, ProcessState $state): array
         return $outputs;
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(string $class, array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/Process/CommandRunnerTaskTest.php b/tests/Task/Process/CommandRunnerTaskTest.php
index 30d047cf..b222c8b7 100644
--- a/tests/Task/Process/CommandRunnerTaskTest.php
+++ b/tests/Task/Process/CommandRunnerTaskTest.php
@@ -114,6 +114,9 @@ private function createTask(): CommandRunnerTask
         return new CommandRunnerTask($kernel);
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/Process/ProcessLauncherTaskTest.php b/tests/Task/Process/ProcessLauncherTaskTest.php
index 76fba37b..1d9ec9c0 100644
--- a/tests/Task/Process/ProcessLauncherTaskTest.php
+++ b/tests/Task/Process/ProcessLauncherTaskTest.php
@@ -75,6 +75,9 @@ private function createTask(): ProcessLauncherTask
         return new ProcessLauncherTask(new NullLogger(), $registry, $this->createStub(KernelInterface::class));
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/PropertySetterTaskTest.php b/tests/Task/PropertySetterTaskTest.php
index d428a645..42fe0eb5 100644
--- a/tests/Task/PropertySetterTaskTest.php
+++ b/tests/Task/PropertySetterTaskTest.php
@@ -77,6 +77,9 @@ public function testScalarInputFailureKeepsErrorContext(): void
         self::assertNull($state->getOutput());
     }
 
+    /**
+     * @param array<string, mixed> $values
+     */
     private function execute(array $values, mixed $input): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/Reporting/AdvancedStatCounterTaskTest.php b/tests/Task/Reporting/AdvancedStatCounterTaskTest.php
index c0a06176..c20e434b 100644
--- a/tests/Task/Reporting/AdvancedStatCounterTaskTest.php
+++ b/tests/Task/Reporting/AdvancedStatCounterTaskTest.php
@@ -96,6 +96,9 @@ public function log($level, string|\Stringable $message, array $context = []): v
         return [$logger->messages, $outputs];
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(string $class, array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/RowAggregatorTaskTest.php b/tests/Task/RowAggregatorTaskTest.php
index cefdd93b..a19f4edb 100644
--- a/tests/Task/RowAggregatorTaskTest.php
+++ b/tests/Task/RowAggregatorTaskTest.php
@@ -118,6 +118,7 @@ public static function invalidOptionsProvider(): iterable
     }
 
     /**
+     * @param array<string, mixed>     $options
      * @param class-string<\Throwable> $exception
      */
     #[DataProvider('invalidOptionsProvider')]
@@ -130,6 +131,9 @@ public function testInvalidOptionsAreRejected(array $options, string $exception)
         $task->initialize($this->createState($options));
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function createState(array $options): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Task/SplitJoinLineTaskTest.php b/tests/Task/SplitJoinLineTaskTest.php
index 3fd958db..bfb21b53 100644
--- a/tests/Task/SplitJoinLineTaskTest.php
+++ b/tests/Task/SplitJoinLineTaskTest.php
@@ -125,6 +125,7 @@ public static function invalidOptionsProvider(): iterable
     }
 
     /**
+     * @param array<string, mixed>     $options
      * @param class-string<\Throwable> $exception
      */
     #[DataProvider('invalidOptionsProvider')]
@@ -136,6 +137,8 @@ public function testInvalidOptionsAreRejected(array $options, string $exception)
     }
 
     /**
+     * @param array<string, mixed> $options
+     *
      * @return array{SplitJoinLineTask, ProcessState}
      */
     private function createTask(array $options): array
@@ -152,6 +155,9 @@ private function createTask(array $options): array
         return [$task, $state];
     }
 
+    /**
+     * @return list<mixed>
+     */
     private function iterate(SplitJoinLineTask $task, ProcessState $state, mixed $input): array
     {
         $outputs = [];
diff --git a/tests/Task/TransformerTaskTest.php b/tests/Task/TransformerTaskTest.php
index ac70be48..3b9cd132 100644
--- a/tests/Task/TransformerTaskTest.php
+++ b/tests/Task/TransformerTaskTest.php
@@ -193,6 +193,9 @@ public function testTransformersOptionMustBeAnArray(): void
         $this->execute(['transformers' => 'trim'], 'value');
     }
 
+    /**
+     * @param array<string, mixed> $options
+     */
     private function execute(array $options, mixed $input): ProcessState
     {
         $processConfiguration = new ProcessConfiguration('test', []);
diff --git a/tests/Transformer/Array/ArrayFilterTransformerTest.php b/tests/Transformer/Array/ArrayFilterTransformerTest.php
index 32f5ba52..422f2b04 100644
--- a/tests/Transformer/Array/ArrayFilterTransformerTest.php
+++ b/tests/Transformer/Array/ArrayFilterTransformerTest.php
@@ -43,6 +43,12 @@ public function testConditionOnArrays(): void
         self::assertSame([2 => ['other' => 'x']], $this->filter($items, ['empty' => ['[type]' => null]]));
     }
 
+    /**
+     * @param array<mixed>         $value
+     * @param array<string, mixed> $condition
+     *
+     * @return array<mixed>
+     */
     private function filter(array $value, array $condition): array
     {
         $transformer = new ArrayFilterTransformer(PropertyAccess::createPropertyAccessor());
diff --git a/tests/Transformer/Serialization/DenormalizeTransformerTest.php b/tests/Transformer/Serialization/DenormalizeTransformerTest.php
index 4b68fba1..e05faa53 100644
--- a/tests/Transformer/Serialization/DenormalizeTransformerTest.php
+++ b/tests/Transformer/Serialization/DenormalizeTransformerTest.php
@@ -73,6 +73,9 @@ public function testContextIsPassedToTheDenormalizer(): void
     public function testClassFormatAndContextArePassedToTheDenormalizer(): void
     {
         $denormalizer = new class implements DenormalizerInterface {
+            /**
+             * @return array<mixed>
+             */
             public function denormalize(mixed $data, string $type, ?string $format = null, array $context = []): array
             {
                 return ['data' => $data, 'type' => $type, 'format' => $format, 'context' => $context];