diff --git a/src/Symfony/Component/Process/ExecutableFinder.php b/src/Symfony/Component/Process/ExecutableFinder.php
index cb4345e7bb..aa52cf367d 100644
--- a/src/Symfony/Component/Process/ExecutableFinder.php
+++ b/src/Symfony/Component/Process/ExecutableFinder.php
@@ -31,10 +31,8 @@ class ExecutableFinder
 
     /**
      * Adds new possible suffix to check for executable.
-     *
-     * @param string $suffix
      */
-    public function addSuffix($suffix)
+    public function addSuffix(string $suffix)
     {
         $this->suffixes[] = $suffix;
     }
@@ -48,7 +46,7 @@ class ExecutableFinder
      *
      * @return string|null The executable path or default value
      */
-    public function find($name, $default = null, array $extraDirs = [])
+    public function find(string $name, string $default = null, array $extraDirs = [])
     {
         if (ini_get('open_basedir')) {
             $searchPath = array_merge(explode(PATH_SEPARATOR, ini_get('open_basedir')), $extraDirs);
diff --git a/src/Symfony/Component/Process/PhpExecutableFinder.php b/src/Symfony/Component/Process/PhpExecutableFinder.php
index 461ea13117..bd0eaf43c0 100644
--- a/src/Symfony/Component/Process/PhpExecutableFinder.php
+++ b/src/Symfony/Component/Process/PhpExecutableFinder.php
@@ -29,11 +29,9 @@ class PhpExecutableFinder
     /**
      * Finds The PHP executable.
      *
-     * @param bool $includeArgs Whether or not include command arguments
-     *
      * @return string|false The PHP executable path or false if it cannot be found
      */
-    public function find($includeArgs = true)
+    public function find(bool $includeArgs = true)
     {
         if ($php = getenv('PHP_BINARY')) {
             if (!is_executable($php)) {
diff --git a/src/Symfony/Component/Process/Pipes/PipesInterface.php b/src/Symfony/Component/Process/Pipes/PipesInterface.php
index 52bbe76b8f..b8e6d26761 100644
--- a/src/Symfony/Component/Process/Pipes/PipesInterface.php
+++ b/src/Symfony/Component/Process/Pipes/PipesInterface.php
@@ -44,7 +44,7 @@ interface PipesInterface
      *
      * @return string[] An array of read data indexed by their fd
      */
-    public function readAndWrite($blocking, $close = false);
+    public function readAndWrite(bool $blocking, bool $close = false);
 
     /**
      * Returns if the current state has open file handles or pipes.
diff --git a/src/Symfony/Component/Process/Pipes/UnixPipes.php b/src/Symfony/Component/Process/Pipes/UnixPipes.php
index 875ee6ab8e..ae81b5655d 100644
--- a/src/Symfony/Component/Process/Pipes/UnixPipes.php
+++ b/src/Symfony/Component/Process/Pipes/UnixPipes.php
@@ -89,7 +89,7 @@ class UnixPipes extends AbstractPipes
     /**
      * {@inheritdoc}
      */
-    public function readAndWrite($blocking, $close = false)
+    public function readAndWrite(bool $blocking, bool $close = false)
     {
         $this->unblock();
         $w = $this->write();
diff --git a/src/Symfony/Component/Process/Pipes/WindowsPipes.php b/src/Symfony/Component/Process/Pipes/WindowsPipes.php
index f44f33b490..b6bfc57103 100644
--- a/src/Symfony/Component/Process/Pipes/WindowsPipes.php
+++ b/src/Symfony/Component/Process/Pipes/WindowsPipes.php
@@ -126,7 +126,7 @@ class WindowsPipes extends AbstractPipes
     /**
      * {@inheritdoc}
      */
-    public function readAndWrite($blocking, $close = false)
+    public function readAndWrite(bool $blocking, bool $close = false)
     {
         $this->unblock();
         $w = $this->write();
diff --git a/src/Symfony/Component/Process/Process.php b/src/Symfony/Component/Process/Process.php
index 71a4aa7a71..92fd775f17 100644
--- a/src/Symfony/Component/Process/Process.php
+++ b/src/Symfony/Component/Process/Process.php
@@ -495,7 +495,7 @@ class Process implements \IteratorAggregate
      * @throws RuntimeException In case --enable-sigchild is activated and the process can't be killed
      * @throws RuntimeException In case of failure
      */
-    public function signal($signal)
+    public function signal(int $signal)
     {
         $this->doSignal($signal, true);
 
@@ -897,7 +897,7 @@ class Process implements \IteratorAggregate
      *
      * @return int The exit-code of the process
      */
-    public function stop($timeout = 10, $signal = null)
+    public function stop(float $timeout = 10, int $signal = null)
     {
         $timeoutMicro = microtime(true) + $timeout;
         if ($this->isRunning()) {
@@ -1028,13 +1028,11 @@ class Process implements \IteratorAggregate
     /**
      * Enables or disables the TTY mode.
      *
-     * @param bool $tty True to enabled and false to disable
-     *
      * @return self The current Process instance
      *
      * @throws RuntimeException In case the TTY mode is not supported
      */
-    public function setTty($tty)
+    public function setTty(bool $tty)
     {
         if ('\\' === \DIRECTORY_SEPARATOR && $tty) {
             throw new RuntimeException('TTY mode is not supported on Windows platform.');
@@ -1062,13 +1060,11 @@ class Process implements \IteratorAggregate
     /**
      * Sets PTY mode.
      *
-     * @param bool $bool
-     *
      * @return self
      */
-    public function setPty($bool)
+    public function setPty(bool $bool)
     {
-        $this->pty = (bool) $bool;
+        $this->pty = $bool;
 
         return $this;
     }
@@ -1102,11 +1098,9 @@ class Process implements \IteratorAggregate
     /**
      * Sets the current working directory.
      *
-     * @param string $cwd The new working directory
-     *
      * @return self The current Process instance
      */
-    public function setWorkingDirectory($cwd)
+    public function setWorkingDirectory(string $cwd)
     {
         $this->cwd = $cwd;
 
@@ -1185,11 +1179,9 @@ class Process implements \IteratorAggregate
     /**
      * Sets whether environment variables will be inherited or not.
      *
-     * @param bool $inheritEnv
-     *
      * @return self The current Process instance
      */
-    public function inheritEnvironmentVariables($inheritEnv = true)
+    public function inheritEnvironmentVariables(bool $inheritEnv = true)
     {
         if (!$inheritEnv) {
             throw new InvalidArgumentException('Not inheriting environment variables is not supported.');
@@ -1316,7 +1308,7 @@ class Process implements \IteratorAggregate
      *
      * @param bool $blocking Whether to use a blocking read call
      */
-    protected function updateStatus($blocking)
+    protected function updateStatus(bool $blocking)
     {
         if (self::STATUS_STARTED !== $this->status) {
             return;
diff --git a/src/Symfony/Component/Process/ProcessUtils.php b/src/Symfony/Component/Process/ProcessUtils.php
index 2f9c4be4de..5b6879ae3a 100644
--- a/src/Symfony/Component/Process/ProcessUtils.php
+++ b/src/Symfony/Component/Process/ProcessUtils.php
@@ -39,7 +39,7 @@ class ProcessUtils
      *
      * @throws InvalidArgumentException In case the input is not valid
      */
-    public static function validateInput($caller, $input)
+    public static function validateInput(string $caller, $input)
     {
         if (null !== $input) {
             if (\is_resource($input)) {