diff --git a/lib/SimpleSAML/Auth/AuthenticationFactory.php b/lib/SimpleSAML/Auth/AuthenticationFactory.php
index e0569d2934a1d1e16bbe00cca644d0261224d891..79a22c06ea5dc42d8407ef445fb5c7076bf37535 100644
--- a/lib/SimpleSAML/Auth/AuthenticationFactory.php
+++ b/lib/SimpleSAML/Auth/AuthenticationFactory.php
@@ -34,7 +34,7 @@ class AuthenticationFactory
      *
      * @return \SimpleSAML\Auth\Simple
      */
-    public function create($as)
+    public function create(string $as): Simple
     {
         return new Simple($as, $this->config, $this->session);
     }
diff --git a/lib/SimpleSAML/Auth/ProcessingChain.php b/lib/SimpleSAML/Auth/ProcessingChain.php
index 5ae89b31ab3d2d84b1739fe0df532f0df48e4eb1..ab83ceb7abdefb20fd2d43b62ffbaec8fd715d93 100644
--- a/lib/SimpleSAML/Auth/ProcessingChain.php
+++ b/lib/SimpleSAML/Auth/ProcessingChain.php
@@ -57,11 +57,8 @@ class ProcessingChain
      * @param array $spMetadata  The metadata for the SP.
      * @param string $mode
      */
-    public function __construct($idpMetadata, $spMetadata, $mode = 'idp')
+    public function __construct(array $idpMetadata, array $spMetadata, string $mode = 'idp')
     {
-        Assert::isArray($idpMetadata);
-        Assert::isArray($spMetadata);
-
         $this->filters = [];
 
         $config = Configuration::getInstance();
@@ -96,7 +93,7 @@ class ProcessingChain
      * @param array $src  Source filters. May be unsorted.
      * @return void
      */
-    private static function addFilters(array &$target, array $src)
+    private static function addFilters(array &$target, array $src): void
     {
         foreach ($src as $filter) {
             $fp = $filter->priority;
@@ -191,9 +188,8 @@ class ProcessingChain
      * @throws \SimpleSAML\Error\UnserializableException
      * @return void
      */
-    public function processState(&$state)
+    public function processState(array &$state): void
     {
-        Assert::isArray($state);
         Assert::true(array_key_exists('ReturnURL', $state) || array_key_exists('ReturnCall', $state));
         Assert::true(!array_key_exists('ReturnURL', $state) || !array_key_exists('ReturnCall', $state));
 
@@ -231,10 +227,8 @@ class ProcessingChain
      * @param array $state  The state we are processing.
      * @return void
      */
-    public static function resumeProcessing($state)
+    public static function resumeProcessing(array $state): void
     {
-        Assert::isArray($state);
-
         while (count($state[self::FILTERS_INDEX]) > 0) {
             $filter = array_shift($state[self::FILTERS_INDEX]);
             try {
@@ -286,9 +280,8 @@ class ProcessingChain
      * @param array &$state  The state we are processing.
      * @return void
      */
-    public function processStatePassive(&$state)
+    public function processStatePassive(array &$state): void
     {
-        Assert::isArray($state);
         // Should not be set when calling this method
         Assert::keyNotExists($state, 'ReturnURL');
 
@@ -307,6 +300,7 @@ class ProcessingChain
         }
     }
 
+
     /**
      * Retrieve a state which has finished processing.
      *
@@ -314,10 +308,8 @@ class ProcessingChain
      * @see State::parseStateID()
      * @return array|null The state referenced by the $id parameter.
      */
-    public static function fetchProcessedState($id)
+    public static function fetchProcessedState(string $id): ?array
     {
-        Assert::string($id);
-
         return State::loadState($id, self::COMPLETED_STAGE);
     }
 }
diff --git a/lib/SimpleSAML/Auth/ProcessingFilter.php b/lib/SimpleSAML/Auth/ProcessingFilter.php
index f3bf7cfeb666f46c067677f2b5dd56d0ffe4fce7..464633d8281fc01b6737367ae1f36d7fb133a06e 100644
--- a/lib/SimpleSAML/Auth/ProcessingFilter.php
+++ b/lib/SimpleSAML/Auth/ProcessingFilter.php
@@ -47,10 +47,8 @@ abstract class ProcessingFilter
      * @param array &$config  Configuration for this filter.
      * @param mixed $reserved  For future use.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
-        Assert::isArray($config);
-
         if (array_key_exists('%priority', $config)) {
             $this->priority = $config['%priority'];
             if (!is_int($this->priority)) {
@@ -69,5 +67,5 @@ abstract class ProcessingFilter
      * @param array &$request  The request we are currently processing.
      * @return void
      */
-    abstract public function process(&$request);
+    abstract public function process(array &$request) : void;
 }
diff --git a/lib/SimpleSAML/Auth/Simple.php b/lib/SimpleSAML/Auth/Simple.php
index 652fcdc7f4a3af06e7b29092dc8ee38e04e7920a..42194223ef67ba16c4785d5cb922695f902d62a1 100644
--- a/lib/SimpleSAML/Auth/Simple.php
+++ b/lib/SimpleSAML/Auth/Simple.php
@@ -40,10 +40,8 @@ class Simple
      * @param \SimpleSAML\Configuration|null $config Optional configuration to use.
      * @param \SimpleSAML\Session|null $session Optional session to use.
      */
-    public function __construct($authSource, Configuration $config = null, Session $session = null)
+    public function __construct(string $authSource, Configuration $config = null, Session $session = null)
     {
-        Assert::string($authSource);
-
         if ($config === null) {
             $config = Configuration::getInstance();
         }
@@ -60,11 +58,11 @@ class Simple
     /**
      * Retrieve the implementing authentication source.
      *
-     * @return Source The authentication source.
+     * @return \SimpleSAML\Auth\Source The authentication source.
      *
      * @throws \SimpleSAML\Error\AuthSource If the requested auth source is unknown.
      */
-    public function getAuthSource()
+    public function getAuthSource(): Source
     {
         $as = Source::getById($this->authSource);
         if ($as === null) {
@@ -82,7 +80,7 @@ class Simple
      *
      * @return bool True if the user is authenticated, false if not.
      */
-    public function isAuthenticated()
+    public function isAuthenticated(): bool
     {
         return $this->session->isValid($this->authSource);
     }
@@ -102,7 +100,7 @@ class Simple
      * @param array $params Various options to the authentication request. See the documentation.
      * @return void
      */
-    public function requireAuth(array $params = [])
+    public function requireAuth(array $params = []): void
     {
         if ($this->session->isValid($this->authSource)) {
             // Already authenticated
@@ -128,7 +126,7 @@ class Simple
      * @param array $params Various options to the authentication request.
      * @return void
      */
-    public function login(array $params = [])
+    public function login(array $params = []): void
     {
         if (array_key_exists('KeepPost', $params)) {
             $keepPost = (bool) $params['KeepPost'];
@@ -188,7 +186,7 @@ class Simple
      * with parameters for the logout. If this parameter is null, we will return to the current page.
      * @return void
      */
-    public function logout($params = null)
+    public function logout($params = null): void
     {
         Assert::true(is_array($params) || is_string($params) || $params === null);
 
@@ -237,9 +235,8 @@ class Simple
      * @param array $state The state after the logout.
      * @return void
      */
-    public static function logoutCompleted($state)
+    public static function logoutCompleted(array $state): void
     {
-        Assert::isArray($state);
         Assert::true(isset($state['ReturnTo']) || isset($state['ReturnCallback']));
 
         if (isset($state['ReturnCallback'])) {
@@ -265,7 +262,7 @@ class Simple
      *
      * @return array The users attributes.
      */
-    public function getAttributes()
+    public function getAttributes(): array
     {
         if (!$this->isAuthenticated()) {
             // Not authenticated
@@ -284,10 +281,8 @@ class Simple
      *
      * @return mixed|null The value of the parameter, or null if it isn't found or we are unauthenticated.
      */
-    public function getAuthData($name)
+    public function getAuthData(string $name)
     {
-        Assert::string($name);
-
         if (!$this->isAuthenticated()) {
             return null;
         }
@@ -301,7 +296,7 @@ class Simple
      *
      * @return array|null All persistent authentication data, or null if we aren't authenticated.
      */
-    public function getAuthDataArray()
+    public function getAuthDataArray(): ?array
     {
         if (!$this->isAuthenticated()) {
             return null;
@@ -319,10 +314,8 @@ class Simple
      *
      * @return string A URL which is suitable for use in link-elements.
      */
-    public function getLoginURL($returnTo = null)
+    public function getLoginURL(?string $returnTo = null): string
     {
-        Assert::nullOrString($returnTo);
-
         if ($returnTo === null) {
             $returnTo = Utils\HTTP::getSelfURL();
         }
@@ -344,10 +337,8 @@ class Simple
      *
      * @return string A URL which is suitable for use in link-elements.
      */
-    public function getLogoutURL($returnTo = null)
+    public function getLogoutURL(?string $returnTo = null): string
     {
-        Assert::nullOrString($returnTo);
-
         if ($returnTo === null) {
             $returnTo = Utils\HTTP::getSelfURL();
         }
@@ -371,7 +362,7 @@ class Simple
      *
      * @return string The URL modified according to the precedence rules.
      */
-    protected function getProcessedURL($url = null)
+    protected function getProcessedURL(?string $url = null): string
     {
         if ($url === null) {
             $url = Utils\HTTP::getSelfURL();
diff --git a/lib/SimpleSAML/Auth/Source.php b/lib/SimpleSAML/Auth/Source.php
index 9f1acd989a27bfb86b559debe15070a4849b2f47..0e260d277e688de420d55e8b9d6e83bb57dfd92d 100644
--- a/lib/SimpleSAML/Auth/Source.php
+++ b/lib/SimpleSAML/Auth/Source.php
@@ -41,10 +41,8 @@ abstract class Source
      * @param array $info Information about this authentication source.
      * @param array &$config Configuration for this authentication source.
      */
-    public function __construct($info, &$config)
+    public function __construct(array $info, array &$config)
     {
-        Assert::isArray($info);
-        Assert::isArray($config);
         Assert::keyExists($info, 'AuthId');
 
         $this->authId = $info['AuthId'];
@@ -59,10 +57,8 @@ abstract class Source
      * @return Source[]  Array of \SimpleSAML\Auth\Source objects of the specified type.
      * @throws \Exception If the authentication source is invalid.
      */
-    public static function getSourcesOfType($type)
+    public static function getSourcesOfType(string $type): array
     {
-        Assert::string($type);
-
         $config = Configuration::getConfig('authsources.php');
 
         $ret = [];
@@ -89,7 +85,7 @@ abstract class Source
      *
      * @return string The ID of this authentication source.
      */
-    public function getAuthId()
+    public function getAuthId(): string
     {
         return $this->authId;
     }
@@ -110,7 +106,7 @@ abstract class Source
      * @param array &$state Information about the current authentication.
      * @return void
      */
-    abstract public function authenticate(&$state);
+    abstract public function authenticate(array &$state): void;
 
 
     /**
@@ -122,7 +118,7 @@ abstract class Source
      * @param array &$state Information about the current authentication.
      * @return void
      */
-    public function reauthenticate(array &$state)
+    public function reauthenticate(array &$state): void
     {
         Assert::notNull($state['ReturnCallback']);
 
@@ -149,9 +145,8 @@ abstract class Source
      * @param array &$state Information about the current authentication.
      * @return void
      */
-    public static function completeAuth(&$state)
+    public static function completeAuth(array &$state): void
     {
-        Assert::isArray($state);
         Assert::keyExists($state, 'LoginCompletedHandler');
 
         State::deleteState($state);
@@ -178,28 +173,22 @@ abstract class Source
      * information. Optional, will default to an empty array.
      * @return void
      */
-    public function initLogin($return, $errorURL = null, array $params = [])
+    public function initLogin($return, ?string $errorURL = null, array $params = []): void
     {
         Assert::True(is_string($return) || is_array($return));
-        Assert::nullOrString($errorURL);
 
         $state = array_merge($params, [
-            '\SimpleSAML\Auth\DefaultAuth.id' => $this->authId, // TODO: remove in 2.0
             '\SimpleSAML\Auth\Source.id' => $this->authId,
-            '\SimpleSAML\Auth\DefaultAuth.Return' => $return, // TODO: remove in 2.0
             '\SimpleSAML\Auth\Source.Return' => $return,
-            '\SimpleSAML\Auth\DefaultAuth.ErrorURL' => $errorURL, // TODO: remove in 2.0
             '\SimpleSAML\Auth\Source.ErrorURL' => $errorURL,
             'LoginCompletedHandler' => [get_class(), 'loginCompleted'],
             'LogoutCallback' => [get_class(), 'logoutCallback'],
             'LogoutCallbackState' => [
-                '\SimpleSAML\Auth\DefaultAuth.logoutSource' => $this->authId, // TODO: remove in 2.0
                 '\SimpleSAML\Auth\Source.logoutSource' => $this->authId,
             ],
         ]);
 
         if (is_string($return)) {
-            $state['\SimpleSAML\Auth\DefaultAuth.ReturnURL'] = $return; // TODO: remove in 2.0
             $state['\SimpleSAML\Auth\Source.ReturnURL'] = $return;
         }
 
@@ -227,9 +216,8 @@ abstract class Source
      * @param array $state The state after the login has completed.
      * @return void
      */
-    public static function loginCompleted($state)
+    public static function loginCompleted(array $state): void
     {
-        Assert::isArray($state);
         Assert::keyExists($state, '\SimpleSAML\Auth\Source.Return');
         Assert::keyExists($state, '\SimpleSAML\Auth\Source.id');
         Assert::keyExists($state, 'Attributes');
@@ -266,9 +254,8 @@ abstract class Source
      * @param array &$state Information about the current logout operation.
      * @return void
      */
-    public function logout(&$state)
+    public function logout(array &$state): void
     {
-        Assert::isArray($state);
         // default logout handler which doesn't do anything
     }
 
@@ -283,9 +270,8 @@ abstract class Source
      * @param array &$state Information about the current authentication.
      * @return void
      */
-    public static function completeLogout(&$state)
+    public static function completeLogout(array &$state): void
     {
-        Assert::isArray($state);
         Assert::keyExists($state, 'LogoutCompletedHandler');
 
         State::deleteState($state);
@@ -360,11 +346,8 @@ abstract class Source
      *     source with the given identifier is found.
      * @throws \SimpleSAML\Error\Exception If no such authentication source is found or it is invalid.
      */
-    public static function getById($authId, $type = null)
+    public static function getById(string $authId, ?string $type = null): ?Source
     {
-        Assert::string($authId);
-        Assert::nullOrString($type);
-
         // for now - load and parse config file
         $config = Configuration::getConfig('authsources.php');
 
@@ -400,9 +383,8 @@ abstract class Source
      * @param array $state State array for the logout operation.
      * @return void
      */
-    public static function logoutCallback($state)
+    public static function logoutCallback(array $state): void
     {
-        Assert::isArray($state);
         Assert::keyExists($state, '\SimpleSAML\Auth\Source.logoutSource');
 
         $source = $state['\SimpleSAML\Auth\Source.logoutSource'];
@@ -433,11 +415,8 @@ abstract class Source
      * @param array  $state The state array passed to the authenticate-function.
      * @return void
      */
-    protected function addLogoutCallback($assoc, $state)
+    protected function addLogoutCallback(string $assoc, array $state): void
     {
-        Assert::string($assoc);
-        Assert::isArray($state);
-
         if (!array_key_exists('LogoutCallback', $state)) {
             // the authentication requester doesn't have a logout callback
             return;
@@ -478,10 +457,8 @@ abstract class Source
      * @param string $assoc The logout association which should be called.
      * @return void
      */
-    protected function callLogoutCallback($assoc)
+    protected function callLogoutCallback(string $assoc): void
     {
-        Assert::string($assoc);
-
         $id = strlen($this->authId) . ':' . $this->authId . $assoc;
 
         $session = Session::getSessionFromRequest();
@@ -511,7 +488,7 @@ abstract class Source
      *
      * @return array The id of all authentication sources.
      */
-    public static function getSources()
+    public static function getSources(): array
     {
         $config = Configuration::getOptionalConfig('authsources.php');
 
@@ -528,7 +505,7 @@ abstract class Source
      * @throws \Exception If the first element of $source is not an identifier for the auth source.
      * @return void
      */
-    protected static function validateSource($source, $id)
+    protected static function validateSource(array $source, string $id): void
     {
         if (!array_key_exists(0, $source) || !is_string($source[0])) {
             throw new \Exception(
diff --git a/lib/SimpleSAML/Auth/SourceFactory.php b/lib/SimpleSAML/Auth/SourceFactory.php
index 1b3077655014e61a30dbe44880be8f165fd460f6..d1a0b1d120bb62613c801098e9d4dc875557dfb4 100644
--- a/lib/SimpleSAML/Auth/SourceFactory.php
+++ b/lib/SimpleSAML/Auth/SourceFactory.php
@@ -9,7 +9,7 @@ interface SourceFactory
     /**
      * @param array $info
      * @param array $config
-     * @return Source
+     * @return \SimpleSAML\Auth\Source
      */
-    public function create(array $info, array $config);
+    public function create(array $info, array $config): Source;
 }
diff --git a/lib/SimpleSAML/Auth/State.php b/lib/SimpleSAML/Auth/State.php
index 4821b8d0ffbd4f47a529bcb6d17f4e73687f2851..9d1f568c894f67eec9ce7b750db0b4349e7449b7 100644
--- a/lib/SimpleSAML/Auth/State.php
+++ b/lib/SimpleSAML/Auth/State.php
@@ -112,7 +112,7 @@ class State
      *
      * @return array The persistent authentication state.
      */
-    public static function getPersistentAuthData(array $state)
+    public static function getPersistentAuthData(array $state): array
     {
         // save persistent authentication data
         $persistent = [];
@@ -154,11 +154,8 @@ class State
      *
      * @return string  Identifier which can be used to retrieve the state later.
      */
-    public static function getStateId(&$state, $rawId = false)
+    public static function getStateId(array &$state, bool $rawId = false): string
     {
-        Assert::isArray($state);
-        Assert::boolean($rawId);
-
         if (!array_key_exists(self::ID, $state)) {
             $state[self::ID] = Utils\Random::generateID();
         }
@@ -203,12 +200,8 @@ class State
      *
      * @return string  Identifier which can be used to retrieve the state later.
      */
-    public static function saveState(&$state, $stage, $rawId = false)
+    public static function saveState(array &$state, string $stage, bool $rawId = false) : string
     {
-        Assert::isArray($state);
-        Assert::string($stage);
-        Assert::boolean($rawId);
-
         $return = self::getStateId($state, $rawId);
         $id = $state[self::ID];
 
@@ -235,7 +228,7 @@ class State
      *
      * @return array  Cloned state data.
      */
-    public static function cloneState(array $state)
+    public static function cloneState(array $state): array
     {
         $clonedState = $state;
 
@@ -268,11 +261,8 @@ class State
      *
      * @return array|null  State information, or NULL if the state is missing and $allowMissing is true.
      */
-    public static function loadState($id, $stage, $allowMissing = false)
+    public static function loadState(string $id, string $stage, bool $allowMissing = false): ?array
     {
-        Assert::string($id);
-        Assert::string($stage);
-        Assert::boolean($allowMissing);
         Logger::debug('Loading state: ' . var_export($id, true));
 
         $sid = self::parseStateID($id);
@@ -329,10 +319,8 @@ class State
      * @param array &$state The state which should be deleted.
      * @return void
      */
-    public static function deleteState(&$state)
+    public static function deleteState(array &$state): void
     {
-        Assert::isArray($state);
-
         if (!array_key_exists(self::ID, $state)) {
             // This state hasn't been saved
             return;
@@ -354,10 +342,8 @@ class State
      * @throws \SimpleSAML\Error\Exception If there is no exception handler defined, it will just throw the $exception.
      * @return void
      */
-    public static function throwException($state, Error\Exception $exception)
+    public static function throwException(array $state, Error\Exception $exception): void
     {
-        Assert::isArray($state);
-
         if (array_key_exists(self::EXCEPTION_HANDLER_URL, $state)) {
             // Save the exception
             $state[self::EXCEPTION_DATA] = $exception;
@@ -392,10 +378,8 @@ class State
      *
      * @return array|null  The state array with the exception, or NULL if no exception was thrown.
      */
-    public static function loadExceptionState($id = null)
+    public static function loadExceptionState(?string $id = null): ?array
     {
-        Assert::nullOrString($id);
-
         if ($id === null) {
             if (!array_key_exists(self::EXCEPTION_PARAM, $_REQUEST)) {
                 // No exception
@@ -423,7 +407,7 @@ class State
      * @author Andreas Solberg, UNINETT AS <andreas.solberg@uninett.no>
      * @author Jaime Perez, UNINETT AS <jaime.perez@uninett.no>
      */
-    public static function parseStateID($stateId)
+    public static function parseStateID(string $stateId): array
     {
         $tmp = explode(':', $stateId, 2);
         $id = $tmp[0];
diff --git a/modules/core/lib/Auth/Process/AttributeAdd.php b/modules/core/lib/Auth/Process/AttributeAdd.php
index 59d1dce47053ef1ae5fce9474aa15b56e8179911..d9b1ffd4c736afad6e8cead6929ef9b481dfd17b 100644
--- a/modules/core/lib/Auth/Process/AttributeAdd.php
+++ b/modules/core/lib/Auth/Process/AttributeAdd.php
@@ -37,12 +37,10 @@ class AttributeAdd extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$config  Configuration information about this filter.
      * @param mixed $reserved  For future use.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
-
         foreach ($config as $name => $values) {
             if (is_int($name)) {
                 if ($values === '%replace') {
@@ -77,9 +75,8 @@ class AttributeAdd extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request  The current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         $attributes = &$request['Attributes'];
diff --git a/modules/core/lib/Auth/Process/AttributeAlter.php b/modules/core/lib/Auth/Process/AttributeAlter.php
index 4fec537e847a5fbac759a3aadba857e6de780343..01970de301d28d0c45be9a56dfa39afff910c5a9 100644
--- a/modules/core/lib/Auth/Process/AttributeAlter.php
+++ b/modules/core/lib/Auth/Process/AttributeAlter.php
@@ -61,12 +61,10 @@ class AttributeAlter extends \SimpleSAML\Auth\ProcessingFilter
      * @param mixed $reserved  For future use.
      * @throws \SimpleSAML\Error\Exception In case of invalid configuration.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
-
         // parse filter configuration
         foreach ($config as $name => $value) {
             if (is_int($name)) {
@@ -105,9 +103,8 @@ class AttributeAlter extends \SimpleSAML\Auth\ProcessingFilter
      * @throws \SimpleSAML\Error\Exception In case of invalid configuration.
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         // get attributes from request
diff --git a/modules/core/lib/Auth/Process/AttributeCopy.php b/modules/core/lib/Auth/Process/AttributeCopy.php
index fe1ae5017595ef40ed9e93ed208010d59ba20180..00dcddfcdec47afbc13eb2c5807d4564f93c85f1 100644
--- a/modules/core/lib/Auth/Process/AttributeCopy.php
+++ b/modules/core/lib/Auth/Process/AttributeCopy.php
@@ -36,12 +36,10 @@ class AttributeCopy extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$config  Configuration information about this filter.
      * @param mixed $reserved  For future use.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
-
         foreach ($config as $source => $destination) {
             if (!is_string($source)) {
                 throw new \Exception('Invalid source attribute name: ' . var_export($source, true));
@@ -62,9 +60,8 @@ class AttributeCopy extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request  The current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         $attributes = &$request['Attributes'];
diff --git a/modules/core/lib/Auth/Process/AttributeLimit.php b/modules/core/lib/Auth/Process/AttributeLimit.php
index ffa79c0b501d849aaa2d40d38e513b1cd6e88f5d..f5f1f4698b4fc8900fd7189e44c9fc18b64b9864 100644
--- a/modules/core/lib/Auth/Process/AttributeLimit.php
+++ b/modules/core/lib/Auth/Process/AttributeLimit.php
@@ -37,12 +37,10 @@ class AttributeLimit extends \SimpleSAML\Auth\ProcessingFilter
      * @param mixed $reserved  For future use
      * @throws \SimpleSAML\Error\Exception If invalid configuration is found.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
-
         foreach ($config as $index => $value) {
             if ($index === 'default') {
                 $this->isDefault = (bool) $value;
@@ -71,7 +69,7 @@ class AttributeLimit extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request  The current request.
      * @return array|null  Array with attribute names, or NULL if no limit is placed.
      */
-    private static function getSPIdPAllowed(array &$request)
+    private static function getSPIdPAllowed(array &$request): ?array
     {
         if (array_key_exists('attributes', $request['Destination'])) {
             // SP Config
@@ -94,9 +92,8 @@ class AttributeLimit extends \SimpleSAML\Auth\ProcessingFilter
      * @throws \SimpleSAML\Error\Exception If invalid configuration is found.
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         assert::keyExists($request, 'Attributes');
 
         if ($this->isDefault) {
diff --git a/modules/core/lib/Auth/Process/AttributeMap.php b/modules/core/lib/Auth/Process/AttributeMap.php
index 2ff61fc2e867310fb8a021451e99d856de765576..63c81aad0e6ba97ec2aba50eff5627e8c5fb45a7 100644
--- a/modules/core/lib/Auth/Process/AttributeMap.php
+++ b/modules/core/lib/Auth/Process/AttributeMap.php
@@ -37,11 +37,10 @@ class AttributeMap extends \SimpleSAML\Auth\ProcessingFilter
      *
      * @throws \Exception If the configuration of the filter is wrong.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
         $mapFiles = [];
 
         foreach ($config as $origName => $newName) {
@@ -82,7 +81,7 @@ class AttributeMap extends \SimpleSAML\Auth\ProcessingFilter
      * @throws \Exception If the filter could not load the requested attribute map file.
      * @return void
      */
-    private function loadMapFile(string $fileName)
+    private function loadMapFile(string $fileName): void
     {
         $config = Configuration::getInstance();
 
@@ -122,9 +121,8 @@ class AttributeMap extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request The current request.
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         $mapped_attributes = [];
diff --git a/modules/core/lib/Auth/Process/AttributeValueMap.php b/modules/core/lib/Auth/Process/AttributeValueMap.php
index 9f640777153e046f6ca71086bd1aa41956b8e1d5..fddd85b8e0b26993250fe94380888ae60326450e 100644
--- a/modules/core/lib/Auth/Process/AttributeValueMap.php
+++ b/modules/core/lib/Auth/Process/AttributeValueMap.php
@@ -54,12 +54,10 @@ class AttributeValueMap extends \SimpleSAML\Auth\ProcessingFilter
      * @param mixed $reserved For future use.
      * @throws \SimpleSAML\Error\Exception If the configuration is not valid.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
-
         // parse configuration
         foreach ($config as $name => $value) {
             if (is_int($name)) {
@@ -112,11 +110,10 @@ class AttributeValueMap extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request The current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
         Logger::debug('Processing the AttributeValueMap filter.');
 
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
         $attributes = &$request['Attributes'];
 
diff --git a/modules/core/lib/Auth/Process/Cardinality.php b/modules/core/lib/Auth/Process/Cardinality.php
index 96f68fbd090d073230639729ccc98aa5bd501dc5..47a4308a937ac9208cd8e383b695ed2fa73a89a1 100644
--- a/modules/core/lib/Auth/Process/Cardinality.php
+++ b/modules/core/lib/Auth/Process/Cardinality.php
@@ -37,10 +37,9 @@ class Cardinality extends \SimpleSAML\Auth\ProcessingFilter
      * @param \SimpleSAML\Utils\HttpAdapter $http  HTTP utility service (handles redirects).
      * @throws \SimpleSAML\Error\Exception
      */
-    public function __construct(&$config, $reserved, Utils\HttpAdapter $http = null)
+    public function __construct(array &$config, $reserved, Utils\HttpAdapter $http = null)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         $this->http = $http ? : new Utils\HttpAdapter();
 
@@ -111,9 +110,8 @@ class Cardinality extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request  The current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         $entityid = false;
diff --git a/modules/core/lib/Auth/Process/CardinalitySingle.php b/modules/core/lib/Auth/Process/CardinalitySingle.php
index cf59af15f59fdf23e70ea6c8e9dea7e324582c71..bcdec278033a0fe34029914ec6fb648bcafc3192 100644
--- a/modules/core/lib/Auth/Process/CardinalitySingle.php
+++ b/modules/core/lib/Auth/Process/CardinalitySingle.php
@@ -47,10 +47,9 @@ class CardinalitySingle extends \SimpleSAML\Auth\ProcessingFilter
      * @param mixed $reserved  For future use.
      * @param \SimpleSAML\Utils\HttpAdapter $http  HTTP utility service (handles redirects).
      */
-    public function __construct(&$config, $reserved, Utils\HttpAdapter $http = null)
+    public function __construct(array &$config, $reserved, Utils\HttpAdapter $http = null)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         $this->http = $http ? : new Utils\HttpAdapter();
 
@@ -86,9 +85,8 @@ class CardinalitySingle extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request  The current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         if (
diff --git a/modules/core/lib/Auth/Process/ExtendIdPSession.php b/modules/core/lib/Auth/Process/ExtendIdPSession.php
index 0366ff2f36f4bea607e40702822eb643db1743ae..764538336e4a5d3e12cf87c7f29256ffd05dfb8d 100644
--- a/modules/core/lib/Auth/Process/ExtendIdPSession.php
+++ b/modules/core/lib/Auth/Process/ExtendIdPSession.php
@@ -18,10 +18,8 @@ class ExtendIdPSession extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$state
      * @return void
      */
-    public function process(&$state)
+    public function process(array &$state): void
     {
-        Assert::isArray($state);
-
         if (empty($state['Expire']) || empty($state['Authority'])) {
             return;
         }
diff --git a/modules/core/lib/Auth/Process/GenerateGroups.php b/modules/core/lib/Auth/Process/GenerateGroups.php
index 9a6ef0d3de93487be498fc1d259ef7e9dadafd70..fe0cd5f3c3ac64573b099b38cf40fac23c77deb3 100644
--- a/modules/core/lib/Auth/Process/GenerateGroups.php
+++ b/modules/core/lib/Auth/Process/GenerateGroups.php
@@ -28,12 +28,10 @@ class GenerateGroups extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$config  Configuration information about this filter.
      * @param mixed $reserved  For future use.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
-
         if (count($config) === 0) {
             // Use default groups
             $this->generateGroupsFrom = [
@@ -60,9 +58,8 @@ class GenerateGroups extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request  The current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         $groups = [];
@@ -105,7 +102,7 @@ class GenerateGroups extends \SimpleSAML\Auth\ProcessingFilter
      * @param array $attributes  The attributes of the user.
      * @return string|null  The realm of the user, or NULL if we are unable to determine the realm.
      */
-    private static function getRealm(array $attributes)
+    private static function getRealm(array $attributes): ?string
     {
         if (!array_key_exists('eduPersonPrincipalName', $attributes)) {
             return null;
diff --git a/modules/core/lib/Auth/Process/LanguageAdaptor.php b/modules/core/lib/Auth/Process/LanguageAdaptor.php
index 1984c4e32b683c538179bdbb52d319246e535bf7..c1cefff0cccbb4906bd03da5229b001bb2f3c7a5 100644
--- a/modules/core/lib/Auth/Process/LanguageAdaptor.php
+++ b/modules/core/lib/Auth/Process/LanguageAdaptor.php
@@ -26,10 +26,9 @@ class LanguageAdaptor extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$config  Configuration information about this filter.
      * @param mixed $reserved  For future use.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         if (array_key_exists('attributename', $config)) {
             $this->langattr = $config['attributename'];
@@ -45,9 +44,8 @@ class LanguageAdaptor extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request  The current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         $attributes = &$request['Attributes'];
diff --git a/modules/core/lib/Auth/Process/PHP.php b/modules/core/lib/Auth/Process/PHP.php
index 5bcf8c0e06d1ab4b7682edd24446a1c5f939125c..541992d0911b4c4a20c2ade50594e91dfd6a2141 100644
--- a/modules/core/lib/Auth/Process/PHP.php
+++ b/modules/core/lib/Auth/Process/PHP.php
@@ -31,12 +31,10 @@ class PHP extends \SimpleSAML\Auth\ProcessingFilter
      *
      * @throws \SimpleSAML\Error\Exception if the 'code' option is not defined.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
-
         if (!isset($config['code'])) {
             throw new Error\Exception("core:PHP: missing mandatory configuration option 'code'.");
         }
@@ -52,9 +50,8 @@ class PHP extends \SimpleSAML\Auth\ProcessingFilter
      *
      * @scrutinizer ignore-unused
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         /**
diff --git a/modules/core/lib/Auth/Process/ScopeAttribute.php b/modules/core/lib/Auth/Process/ScopeAttribute.php
index b1228a1f68fd997f634ec5d9ec17bde26202258d..8c13339b02c74dc2c5fe7aeff961ea5bdfef0ed9 100644
--- a/modules/core/lib/Auth/Process/ScopeAttribute.php
+++ b/modules/core/lib/Auth/Process/ScopeAttribute.php
@@ -50,10 +50,9 @@ class ScopeAttribute extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$config  Configuration information about this filter.
      * @param mixed $reserved  For future use.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         $cfg = Configuration::loadFromArray($config, 'ScopeAttribute');
 
@@ -70,9 +69,8 @@ class ScopeAttribute extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request  The current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         $attributes = &$request['Attributes'];
diff --git a/modules/core/lib/Auth/Process/ScopeFromAttribute.php b/modules/core/lib/Auth/Process/ScopeFromAttribute.php
index a8a44012b34b34e44c2f546937aaa9132378196c..eec2cf68b388c5e068b059f8d863835bb9247f54 100644
--- a/modules/core/lib/Auth/Process/ScopeFromAttribute.php
+++ b/modules/core/lib/Auth/Process/ScopeFromAttribute.php
@@ -47,10 +47,9 @@ class ScopeFromAttribute extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$config  Configuration information about this filter.
      * @param mixed $reserved  For future use.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         $cfg = Configuration::loadFromArray($config, 'ScopeFromAttribute');
         $this->targetAttribute = $cfg->getString('targetAttribute');
@@ -64,9 +63,8 @@ class ScopeFromAttribute extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request  The current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         $attributes = &$request['Attributes'];
diff --git a/modules/core/lib/Auth/Process/StatisticsWithAttribute.php b/modules/core/lib/Auth/Process/StatisticsWithAttribute.php
index 07ecc94d0924278940e52f921eb2087c96c9ab9b..66fedc7617d08d8e6b7ea665d5c5f5bc743937f0 100644
--- a/modules/core/lib/Auth/Process/StatisticsWithAttribute.php
+++ b/modules/core/lib/Auth/Process/StatisticsWithAttribute.php
@@ -38,12 +38,10 @@ class StatisticsWithAttribute extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$config  Configuration information about this filter.
      * @param mixed $reserved  For future use.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
-
         if (array_key_exists('attributename', $config)) {
             $this->attribute = $config['attributename'];
             if (!is_string($this->attribute)) {
@@ -70,9 +68,8 @@ class StatisticsWithAttribute extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$state  The current state.
      * @return void
      */
-    public function process(&$state)
+    public function process(array &$state): void
     {
-        Assert::isArray($state);
         Assert::keyExists($state, 'Attributes');
 
         $logAttribute = 'NA';
@@ -101,6 +98,7 @@ class StatisticsWithAttribute extends \SimpleSAML\Auth\ProcessingFilter
         Logger::stats($isPassive . $this->typeTag . ' ' . $dest . ' ' . $source . ' ' . $logAttribute);
     }
 
+
     /**
      * @param string &$direction  Either 'Source' or 'Destination'.
      * @param array $state  The current state.
diff --git a/modules/core/lib/Auth/Process/TargetedID.php b/modules/core/lib/Auth/Process/TargetedID.php
index 1e8273bd974e1a9f89475b65a99acdbb5b577bb4..5ed6278398c7a8516964389ffb524113fac7008b 100644
--- a/modules/core/lib/Auth/Process/TargetedID.php
+++ b/modules/core/lib/Auth/Process/TargetedID.php
@@ -61,12 +61,10 @@ class TargetedID extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$config  Configuration information about this filter.
      * @param mixed $reserved  For future use.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
-
         if (array_key_exists('attributename', $config)) {
             $this->attribute = $config['attributename'];
             if (!is_string($this->attribute)) {
@@ -89,9 +87,8 @@ class TargetedID extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$state  The current state.
      * @return void
      */
-    public function process(&$state)
+    public function process(array &$state): void
     {
-        Assert::isArray($state);
         Assert::keyExists($state, 'Attributes');
 
         if ($this->attribute === null) {
diff --git a/modules/core/lib/Auth/Process/WarnShortSSOInterval.php b/modules/core/lib/Auth/Process/WarnShortSSOInterval.php
index e75b56cd7cac3eac4ca352a1010861dc3873de42..2ce421d3cf59de276d9a51ff9cf18f584bd740e2 100644
--- a/modules/core/lib/Auth/Process/WarnShortSSOInterval.php
+++ b/modules/core/lib/Auth/Process/WarnShortSSOInterval.php
@@ -26,10 +26,8 @@ class WarnShortSSOInterval extends \SimpleSAML\Auth\ProcessingFilter
      * @param array $state  The state of the response.
      * @return void
      */
-    public function process(&$state)
+    public function process(array &$state): void
     {
-        Assert::isArray($state);
-
         if (!array_key_exists('PreviousSSOTimestamp', $state)) {
             /*
              * No timestamp from the previous SSO to this SP. This is the first
diff --git a/modules/core/lib/Auth/UserPassBase.php b/modules/core/lib/Auth/UserPassBase.php
index 919cda96af81d59c34738e4809ba94fe260df35e..4b2ac3452e52f067564bc3f42b2f1848928bf6fd 100644
--- a/modules/core/lib/Auth/UserPassBase.php
+++ b/modules/core/lib/Auth/UserPassBase.php
@@ -135,7 +135,7 @@ abstract class UserPassBase extends \SimpleSAML\Auth\Source
      * @param string|null $forcedUsername  The forced username.
      * @return void
      */
-    public function setForcedUsername($forcedUsername)
+    public function setForcedUsername($forcedUsername): void
     {
         Assert::nullOrString($forcedUsername);
         $this->forcedUsername = $forcedUsername;
@@ -145,7 +145,7 @@ abstract class UserPassBase extends \SimpleSAML\Auth\Source
      * Return login links from configuration
      * @return array
      */
-    public function getLoginLinks()
+    public function getLoginLinks(): array
     {
         return $this->loginLinks;
     }
@@ -155,7 +155,7 @@ abstract class UserPassBase extends \SimpleSAML\Auth\Source
      * Getter for the authsource config option remember.username.enabled
      * @return bool
      */
-    public function getRememberUsernameEnabled()
+    public function getRememberUsernameEnabled(): bool
     {
         return $this->rememberUsernameEnabled;
     }
@@ -165,7 +165,7 @@ abstract class UserPassBase extends \SimpleSAML\Auth\Source
      * Getter for the authsource config option remember.username.checked
      * @return bool
      */
-    public function getRememberUsernameChecked()
+    public function getRememberUsernameChecked(): bool
     {
         return $this->rememberUsernameChecked;
     }
@@ -175,7 +175,7 @@ abstract class UserPassBase extends \SimpleSAML\Auth\Source
      * Check if the "remember me" feature is enabled.
      * @return bool TRUE if enabled, FALSE otherwise.
      */
-    public function isRememberMeEnabled()
+    public function isRememberMeEnabled(): bool
     {
         return $this->rememberMeEnabled;
     }
@@ -185,7 +185,7 @@ abstract class UserPassBase extends \SimpleSAML\Auth\Source
      * Check if the "remember me" checkbox should be checked.
      * @return bool TRUE if enabled, FALSE otherwise.
      */
-    public function isRememberMeChecked()
+    public function isRememberMeChecked(): bool
     {
         return $this->rememberMeChecked;
     }
@@ -200,10 +200,8 @@ abstract class UserPassBase extends \SimpleSAML\Auth\Source
      * @param array &$state  Information about the current authentication.
      * @return void
      */
-    public function authenticate(&$state)
+    public function authenticate(array &$state): void
     {
-        Assert::isArray($state);
-
         /*
          * Save the identifier of this authentication source, so that we can
          * retrieve it later. This allows us to call the login()-function on
@@ -275,7 +273,7 @@ abstract class UserPassBase extends \SimpleSAML\Auth\Source
      * @param string $password  The password the user wrote.
      * @return array  Associative array with the user's attributes.
      */
-    abstract protected function login($username, $password);
+    abstract protected function login($username, $password): array;
 
 
     /**
@@ -290,12 +288,8 @@ abstract class UserPassBase extends \SimpleSAML\Auth\Source
      * @param string $password  The password the user wrote.
      * @return void
      */
-    public static function handleLogin($authStateId, $username, $password)
+    public static function handleLogin(string $authStateId, string $username, string $password)
     {
-        Assert::string($authStateId);
-        Assert::string($username);
-        Assert::string($password);
-
         // Here we retrieve the state array we saved in the authenticate-function.
         /** @var array $state */
         $state = Auth\State::loadState($authStateId, self::STAGEID);
diff --git a/modules/core/lib/Auth/UserPassOrgBase.php b/modules/core/lib/Auth/UserPassOrgBase.php
index 608ca86726a1c601d8ff94d9121e2b65e78bd09c..dce40e894c239fc01da405e9d83c76f9ad186d92 100644
--- a/modules/core/lib/Auth/UserPassOrgBase.php
+++ b/modules/core/lib/Auth/UserPassOrgBase.php
@@ -143,7 +143,7 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      * @param string $usernameOrgMethod  The method which should be used.
      * @return void
      */
-    protected function setUsernameOrgMethod($usernameOrgMethod)
+    protected function setUsernameOrgMethod($usernameOrgMethod): void
     {
         Assert::oneOf($usernameOrgMethod, ['none', 'allow', 'force']);
 
@@ -161,7 +161,7 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      *
      * @return string  The method which should be used.
      */
-    public function getUsernameOrgMethod()
+    public function getUsernameOrgMethod(): string
     {
         return $this->usernameOrgMethod;
     }
@@ -171,7 +171,7 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      * Getter for the authsource config option remember.username.enabled
      * @return bool
      */
-    public function getRememberUsernameEnabled()
+    public function getRememberUsernameEnabled(): bool
     {
         return $this->rememberUsernameEnabled;
     }
@@ -181,7 +181,7 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      * Getter for the authsource config option remember.username.checked
      * @return bool
      */
-    public function getRememberUsernameChecked()
+    public function getRememberUsernameChecked(): bool
     {
         return $this->rememberUsernameChecked;
     }
@@ -191,7 +191,7 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      * Getter for the authsource config option remember.organization.enabled
      * @return bool
      */
-    public function getRememberOrganizationEnabled()
+    public function getRememberOrganizationEnabled(): bool
     {
         return $this->rememberOrganizationEnabled;
     }
@@ -201,7 +201,7 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      * Getter for the authsource config option remember.organization.checked
      * @return bool
      */
-    public function getRememberOrganizationChecked()
+    public function getRememberOrganizationChecked(): bool
     {
         return $this->rememberOrganizationChecked;
     }
@@ -216,10 +216,8 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      * @param array &$state  Information about the current authentication.
      * @return void
      */
-    public function authenticate(&$state)
+    public function authenticate(array &$state): void
     {
-        Assert::isArray($state);
-
         // We are going to need the authId in order to retrieve this authentication source later
         $state[self::AUTHID] = $this->authId;
 
@@ -245,7 +243,7 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      * @param string $organization  The id of the organization the user chose.
      * @return array  Associative array with the user's attributes.
      */
-    abstract protected function login($username, $password, $organization);
+    abstract protected function login(string $username, string $password, string $organization): array;
 
 
     /**
@@ -258,7 +256,7 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      *
      * @return array  Associative array with the organizations.
      */
-    abstract protected function getOrganizations();
+    abstract protected function getOrganizations(): array;
 
 
     /**
@@ -274,13 +272,12 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      * @param string $organization  The id of the organization the user chose.
      * @return void
      */
-    public static function handleLogin($authStateId, $username, $password, $organization)
-    {
-        Assert::string($authStateId);
-        Assert::string($username);
-        Assert::string($password);
-        assert::string($organization);
-
+    public static function handleLogin(
+        string $authStateId,
+        string $username,
+        string $password,
+        string $organization
+   ): void {
         /* Retrieve the authentication state. */
         /** @var array $state */
         $state = Auth\State::loadState($authStateId, self::STAGEID);
@@ -339,10 +336,8 @@ abstract class UserPassOrgBase extends \SimpleSAML\Auth\Source
      * @return array|null  Array of organizations. NULL if the user must enter the
      *         organization as part of the username.
      */
-    public static function listOrganizations($authStateId)
+    public static function listOrganizations(string $authStateId): ?array
     {
-        Assert::string($authStateId);
-
         /* Retrieve the authentication state. */
         /** @var array $state */
         $state = Auth\State::loadState($authStateId, self::STAGEID);
diff --git a/modules/exampleauth/lib/Auth/Process/RedirectTest.php b/modules/exampleauth/lib/Auth/Process/RedirectTest.php
index 88e6da07fac2005786dbb8a360faba0d2f1fbe5e..27b575f0f9ae89cc6ad3fff92f79cc4949bf4493 100644
--- a/modules/exampleauth/lib/Auth/Process/RedirectTest.php
+++ b/modules/exampleauth/lib/Auth/Process/RedirectTest.php
@@ -21,9 +21,8 @@ class RedirectTest extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$state  The state we should update.
      * @return void
      */
-    public function process(&$state)
+    public function process(array &$state): void
     {
-        Assert::isArray($state);
         Assert::keyExists($state, 'Attributes');
 
         // To check whether the state is saved correctly
diff --git a/modules/exampleauth/lib/Auth/Source/External.php b/modules/exampleauth/lib/Auth/Source/External.php
index b6e8101d80385f00fe0813472284410b92562fe8..966ab4b57d57b09e78126709715572cc396041d2 100644
--- a/modules/exampleauth/lib/Auth/Source/External.php
+++ b/modules/exampleauth/lib/Auth/Source/External.php
@@ -61,7 +61,7 @@ class External extends \SimpleSAML\Auth\Source
      *
      * @return array|null  The user's attributes, or NULL if the user isn't authenticated.
      */
-    private function getUser()
+    private function getUser(): ?array
     {
         /*
          * In this example we assume that the attributes are
@@ -107,7 +107,7 @@ class External extends \SimpleSAML\Auth\Source
      * @param array &$state  Information about the current authentication.
      * @return void
      */
-    public function authenticate(&$state)
+    public function authenticate(array &$state): void
     {
         Assert::isArray($state);
 
@@ -194,7 +194,7 @@ class External extends \SimpleSAML\Auth\Source
      * @throws \SimpleSAML\Error\BadRequest
      * @throws \SimpleSAML\Error\Exception
      */
-    public static function resume()
+    public static function resume(): void
     {
         /*
          * First we need to restore the $state-array. We should have the identifier for
@@ -271,7 +271,7 @@ class External extends \SimpleSAML\Auth\Source
      * @param array &$state  The logout state array.
      * @return void
      */
-    public function logout(&$state)
+    public function logout(array &$state): void
     {
         Assert::isArray($state);
 
diff --git a/modules/exampleauth/lib/Auth/Source/StaticSource.php b/modules/exampleauth/lib/Auth/Source/StaticSource.php
index 35deb54794a4df15f72417ce5fa675629be29b85..21c86c697944e374f31d36834bb1c4f3fecfa0f2 100644
--- a/modules/exampleauth/lib/Auth/Source/StaticSource.php
+++ b/modules/exampleauth/lib/Auth/Source/StaticSource.php
@@ -55,7 +55,7 @@ class StaticSource extends \SimpleSAML\Auth\Source
      * @param array &$state  Information about the current authentication.
      * @return void
      */
-    public function authenticate(&$state)
+    public function authenticate(array &$state): void
     {
         Assert::isArray($state);
         $state['Attributes'] = $this->attributes;
diff --git a/modules/multiauth/lib/Auth/Source/MultiAuth.php b/modules/multiauth/lib/Auth/Source/MultiAuth.php
index 9592429730559dc981b6b8da9709269fa10a86e9..4db78af18a2af252306ff1920ef7bba00a088043 100644
--- a/modules/multiauth/lib/Auth/Source/MultiAuth.php
+++ b/modules/multiauth/lib/Auth/Source/MultiAuth.php
@@ -139,7 +139,7 @@ class MultiAuth extends \SimpleSAML\Auth\Source
      * @param array &$state Information about the current authentication.
      * @return void
      */
-    public function authenticate(&$state)
+    public function authenticate(array &$state) : void
     {
         Assert::isArray($state);
 
@@ -234,7 +234,7 @@ class MultiAuth extends \SimpleSAML\Auth\Source
      * @param array &$state Information about the current logout operation.
      * @return void
      */
-    public function logout(&$state)
+    public function logout(array &$state) : void
     {
         Assert::isArray($state);
 
diff --git a/modules/saml/lib/Auth/Process/AttributeNameID.php b/modules/saml/lib/Auth/Process/AttributeNameID.php
index 7e5647cf8b230fe7dd05b2feb84236b4884a2201..6c5db9bff29f6cadd31321f3241b904959c108c8 100644
--- a/modules/saml/lib/Auth/Process/AttributeNameID.php
+++ b/modules/saml/lib/Auth/Process/AttributeNameID.php
@@ -32,10 +32,9 @@ class AttributeNameID extends \SimpleSAML\Module\saml\BaseNameIDGenerator
      *
      * @throws \SimpleSAML\Error\Exception If the required options 'Format' or 'attribute' are missing.
      */
-    public function __construct($config, $reserved)
+    public function __construct(array $config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         if (!isset($config['Format'])) {
             throw new Error\Exception("AttributeNameID: Missing required option 'Format'.");
@@ -55,7 +54,7 @@ class AttributeNameID extends \SimpleSAML\Module\saml\BaseNameIDGenerator
      * @param array $state The state array.
      * @return string|null The NameID value.
      */
-    protected function getValue(array &$state)
+    protected function getValue(array &$state): ?string
     {
         if (!isset($state['Attributes'][$this->attribute]) || count($state['Attributes'][$this->attribute]) === 0) {
             Logger::warning(
diff --git a/modules/saml/lib/Auth/Process/AuthnContextClassRef.php b/modules/saml/lib/Auth/Process/AuthnContextClassRef.php
index e717accfdd91e6eb43f9854bc3e4d9b16e16122d..e1cb26b6619488b4c21b82b1fc383801c29668ba 100644
--- a/modules/saml/lib/Auth/Process/AuthnContextClassRef.php
+++ b/modules/saml/lib/Auth/Process/AuthnContextClassRef.php
@@ -30,10 +30,9 @@ class AuthnContextClassRef extends \SimpleSAML\Auth\ProcessingFilter
      *
      * @throws \SimpleSAML\Error\Exception if the mandatory 'AuthnContextClassRef' option is missing.
      */
-    public function __construct($config, $reserved)
+    public function __construct(array $config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         if (!isset($config['AuthnContextClassRef'])) {
             throw new Error\Exception('Missing AuthnContextClassRef option in processing filter.');
@@ -49,10 +48,8 @@ class AuthnContextClassRef extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$state The state array for this request.
      * @return void
      */
-    public function process(&$state)
+    public function process(array &$state): void
     {
-        Assert::isArray($state);
-
         $state['saml:AuthnContextClassRef'] = $this->authnContextClassRef;
     }
 }
diff --git a/modules/saml/lib/Auth/Process/ExpectedAuthnContextClassRef.php b/modules/saml/lib/Auth/Process/ExpectedAuthnContextClassRef.php
index 0edc8e00e4cc17d6018f961f440eff16d25edd71..cd64ac6ad8c89cf460d66dfab731b62c45c594ea 100644
--- a/modules/saml/lib/Auth/Process/ExpectedAuthnContextClassRef.php
+++ b/modules/saml/lib/Auth/Process/ExpectedAuthnContextClassRef.php
@@ -51,11 +51,10 @@ class ExpectedAuthnContextClassRef extends \SimpleSAML\Auth\ProcessingFilter
      *
      * @throws \SimpleSAML\Error\Exception if the mandatory 'accepted' configuration option is missing.
      */
-    public function __construct($config, $reserved)
+    public function __construct(array $config, $reserved)
     {
         parent::__construct($config, $reserved);
 
-        Assert::isArray($config);
         if (empty($config['accepted'])) {
             Logger::error(
                 'ExpectedAuthnContextClassRef: Configuration error. There is no accepted AuthnContextClassRef.'
@@ -73,9 +72,8 @@ class ExpectedAuthnContextClassRef extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request The current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
-        Assert::isArray($request);
         Assert::keyExists($request, 'Attributes');
 
         $this->AuthnContextClassRef = $request['saml:sp:State']['saml:sp:AuthnContext'];
@@ -99,7 +97,7 @@ class ExpectedAuthnContextClassRef extends \SimpleSAML\Auth\ProcessingFilter
      * @param array $request
      * @return void
      */
-    protected function unauthorized(&$request)
+    protected function unauthorized(&$request): void
     {
         Logger::error(
             'ExpectedAuthnContextClassRef: Invalid authentication context: ' . strval($this->AuthnContextClassRef) .
diff --git a/modules/saml/lib/Auth/Process/FilterScopes.php b/modules/saml/lib/Auth/Process/FilterScopes.php
index 8b33e723a18bd1a9e1b64b3bc85b230146b542d5..39b35206989a4e996e5aa7b5d158f2519164678b 100644
--- a/modules/saml/lib/Auth/Process/FilterScopes.php
+++ b/modules/saml/lib/Auth/Process/FilterScopes.php
@@ -33,10 +33,9 @@ class FilterScopes extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$config Configuration for this filter.
      * @param mixed $reserved For future use.
      */
-    public function __construct(&$config, $reserved)
+    public function __construct(array &$config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         if (array_key_exists('attributes', $config) && !empty($config['attributes'])) {
             $this->scopedAttributes = $config['attributes'];
@@ -50,7 +49,7 @@ class FilterScopes extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$request the current request
      * @return void
      */
-    public function process(&$request)
+    public function process(array &$request): void
     {
         $src = $request['Source'];
         if (!count($this->scopedAttributes)) {
diff --git a/modules/saml/lib/Auth/Process/NameIDAttribute.php b/modules/saml/lib/Auth/Process/NameIDAttribute.php
index e7e5655e5cdc300965fafb5fa744be58c43dff20..8020e30e41d1c3abff0b6e11af8759d58c5b1408 100644
--- a/modules/saml/lib/Auth/Process/NameIDAttribute.php
+++ b/modules/saml/lib/Auth/Process/NameIDAttribute.php
@@ -38,10 +38,9 @@ class NameIDAttribute extends \SimpleSAML\Auth\ProcessingFilter
      * @param array $config Configuration information about this filter.
      * @param mixed $reserved For future use.
      */
-    public function __construct($config, $reserved)
+    public function __construct(array $config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         if (isset($config['attribute'])) {
             $this->attribute = (string) $config['attribute'];
@@ -109,9 +108,8 @@ class NameIDAttribute extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$state The request state.
      * @return void
      */
-    public function process(&$state)
+    public function process(array &$state): void
     {
-        Assert::isArray($state);
         Assert::keyExists($state['Source'], 'entityid');
         Assert::keyExists($state['Destination'], 'entityid');
 
diff --git a/modules/saml/lib/Auth/Process/PersistentNameID.php b/modules/saml/lib/Auth/Process/PersistentNameID.php
index 07965c8e0101d0b9cd97d21f21fd79595febc7c6..c36eaf62e88b831affa2c4ab61846771d67bb10b 100644
--- a/modules/saml/lib/Auth/Process/PersistentNameID.php
+++ b/modules/saml/lib/Auth/Process/PersistentNameID.php
@@ -34,10 +34,9 @@ class PersistentNameID extends \SimpleSAML\Module\saml\BaseNameIDGenerator
      *
      * @throws \SimpleSAML\Error\Exception If the required option 'attribute' is missing.
      */
-    public function __construct($config, $reserved)
+    public function __construct(array $config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         $this->format = Constants::NAMEID_PERSISTENT;
 
@@ -54,7 +53,7 @@ class PersistentNameID extends \SimpleSAML\Module\saml\BaseNameIDGenerator
      * @param array $state The state array.
      * @return string|null The NameID value.
      */
-    protected function getValue(array &$state)
+    protected function getValue(array &$state): ?string
     {
         if (!isset($state['Destination']['entityid'])) {
             Logger::warning('No SP entity ID - not generating persistent NameID.');
diff --git a/modules/saml/lib/Auth/Process/PersistentNameID2TargetedID.php b/modules/saml/lib/Auth/Process/PersistentNameID2TargetedID.php
index 3c98c4405e3575e8e5b8b75e586b5b0a4463ab11..f9bfd25ba4ff4f49d8b2f19b4f9eee95ef8e15ac 100644
--- a/modules/saml/lib/Auth/Process/PersistentNameID2TargetedID.php
+++ b/modules/saml/lib/Auth/Process/PersistentNameID2TargetedID.php
@@ -38,10 +38,9 @@ class PersistentNameID2TargetedID extends \SimpleSAML\Auth\ProcessingFilter
      * @param array $config Configuration information about this filter.
      * @param mixed $reserved For future use.
      */
-    public function __construct($config, $reserved)
+    public function __construct(array $config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         if (isset($config['attribute'])) {
             $this->attribute = (string) $config['attribute'];
@@ -63,9 +62,8 @@ class PersistentNameID2TargetedID extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$state The request state.
      * @return void
      */
-    public function process(&$state)
+    public function process(array &$state): void
     {
-        Assert::isArray($state);
         if (!isset($state['saml:NameID'][Constants::NAMEID_PERSISTENT])) {
             Logger::warning(
                 'Unable to generate eduPersonTargetedID because no persistent NameID was available.'
diff --git a/modules/saml/lib/Auth/Process/SQLPersistentNameID.php b/modules/saml/lib/Auth/Process/SQLPersistentNameID.php
index 76a676bf15b53ceb0736ef73ef97013be440608d..abf6d580976d3bca4b776391ebb8a58a220088b8 100644
--- a/modules/saml/lib/Auth/Process/SQLPersistentNameID.php
+++ b/modules/saml/lib/Auth/Process/SQLPersistentNameID.php
@@ -61,10 +61,9 @@ class SQLPersistentNameID extends \SimpleSAML\Module\saml\BaseNameIDGenerator
      *
      * @throws \SimpleSAML\Error\Exception If the 'attribute' option is not specified.
      */
-    public function __construct($config, $reserved)
+    public function __construct(array $config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         $this->format = Constants::NAMEID_PERSISTENT;
 
@@ -99,7 +98,7 @@ class SQLPersistentNameID extends \SimpleSAML\Module\saml\BaseNameIDGenerator
      *
      * @throws \SimpleSAML\Module\saml\Error if the NameID creation policy is invalid.
      */
-    protected function getValue(array &$state)
+    protected function getValue(array &$state): ?string
     {
         if (!isset($state['saml:NameIDFormat']) && !$this->allowUnspecified) {
             Logger::debug(
diff --git a/modules/saml/lib/Auth/Process/TransientNameID.php b/modules/saml/lib/Auth/Process/TransientNameID.php
index 4f82a7fbb38b40a55dc9d62f0736477b1bacdd6a..932ef696ac8dba65482435a598c2e43dc912cce8 100644
--- a/modules/saml/lib/Auth/Process/TransientNameID.php
+++ b/modules/saml/lib/Auth/Process/TransientNameID.php
@@ -22,10 +22,9 @@ class TransientNameID extends \SimpleSAML\Module\saml\BaseNameIDGenerator
      * @param array $config Configuration information about this filter.
      * @param mixed $reserved For future use.
      */
-    public function __construct($config, $reserved)
+    public function __construct(array $config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         $this->format = Constants::NAMEID_TRANSIENT;
     }
@@ -37,7 +36,7 @@ class TransientNameID extends \SimpleSAML\Module\saml\BaseNameIDGenerator
      * @param array $state The state array.
      * @return string|null The NameID value.
      */
-    protected function getValue(array &$state)
+    protected function getValue(array &$state): ?string
     {
         return Utils\Random::generateID();
     }
diff --git a/modules/saml/lib/Auth/Source/SP.php b/modules/saml/lib/Auth/Source/SP.php
index 91f2bd24b49830289ffb71f8c2777901014d8b25..0d62b13b24217ba7e5443a2b781cdb1513771069 100644
--- a/modules/saml/lib/Auth/Source/SP.php
+++ b/modules/saml/lib/Auth/Source/SP.php
@@ -730,7 +730,7 @@ class SP extends \SimpleSAML\Auth\Source
      * @param array &$state  Information about the current authentication.
      * @return void
      */
-    public function authenticate(&$state)
+    public function authenticate(array &$state) : void
     {
         Assert::isArray($state);
 
@@ -789,7 +789,7 @@ class SP extends \SimpleSAML\Auth\Source
      * @param array &$state  Information about the current authentication.
      * @return void
      */
-    public function reauthenticate(array &$state)
+    public function reauthenticate(array &$state) : void
     {
         $session = Session::getSessionFromRequest();
         $data = $session->getAuthState($this->authId);
@@ -1034,7 +1034,7 @@ class SP extends \SimpleSAML\Auth\Source
      * @param array $state  The logout state.
      * @return void
      */
-    public function logout(&$state)
+    public function logout(array &$state) : void
     {
         Assert::isArray($state);
         Assert::keyExists($state, 'saml:logout:Type');
diff --git a/modules/saml/lib/BaseNameIDGenerator.php b/modules/saml/lib/BaseNameIDGenerator.php
index bffb4435eb5d50cf6105b49c6f8ec83a06a6f8b0..0e7dc5c9cf67213e52e4e8a22f814373dce1a98f 100644
--- a/modules/saml/lib/BaseNameIDGenerator.php
+++ b/modules/saml/lib/BaseNameIDGenerator.php
@@ -55,10 +55,9 @@ abstract class BaseNameIDGenerator extends \SimpleSAML\Auth\ProcessingFilter
      * @param array $config  Configuration information about this filter.
      * @param mixed $reserved  For future use.
      */
-    public function __construct($config, $reserved)
+    public function __construct(array $config, $reserved)
     {
         parent::__construct($config, $reserved);
-        Assert::isArray($config);
 
         if (isset($config['NameQualifier'])) {
             $this->nameQualifier = $config['NameQualifier'];
@@ -88,9 +87,8 @@ abstract class BaseNameIDGenerator extends \SimpleSAML\Auth\ProcessingFilter
      * @param array &$state  The request state.
      * @return void
      */
-    public function process(&$state)
+    public function process(array &$state): void
     {
-        Assert::isArray($state);
         Assert::string($this->format);
 
         $value = $this->getValue($state);