diff --git a/src/Composer/Command/BaseDependencyCommand.php b/src/Composer/Command/BaseDependencyCommand.php
index f02eb8e13..e4be22bac 100644
--- a/src/Composer/Command/BaseDependencyCommand.php
+++ b/src/Composer/Command/BaseDependencyCommand.php
@@ -209,8 +209,9 @@ class BaseDependencyCommand extends BaseCommand
     /**
      * Recursively prints a tree of the selected results.
      *
-     * @param array  $results
-     * @param string $prefix
+     * @param array  $results Results to be printed at this level.
+     * @param string $prefix  Prefix of the current tree level.
+     * @param int    $level   Current level of recursion.
      */
     protected function printTree($results, $prefix = '', $level = 1)
     {
diff --git a/src/Composer/Command/CreateProjectCommand.php b/src/Composer/Command/CreateProjectCommand.php
index a4a48e176..bb0fb0bc8 100644
--- a/src/Composer/Command/CreateProjectCommand.php
+++ b/src/Composer/Command/CreateProjectCommand.php
@@ -362,6 +362,7 @@ EOT
      * @param InputInterface $input
      * @param bool           $preferSource
      * @param bool           $preferDist
+     * @param bool           $keepVcsRequiresPreferSource
      */
     protected function updatePreferredOptions(Config $config, InputInterface $input, &$preferSource, &$preferDist, $keepVcsRequiresPreferSource = false)
     {
diff --git a/src/Composer/Command/LicensesCommand.php b/src/Composer/Command/LicensesCommand.php
index 7cb250607..889a2920b 100644
--- a/src/Composer/Command/LicensesCommand.php
+++ b/src/Composer/Command/LicensesCommand.php
@@ -114,6 +114,8 @@ EOT
      *
      * @param RepositoryInterface $repo
      * @param PackageInterface    $package
+     * @param array               $bucket
+     * @return array
      */
     private function filterRequiredPackages(RepositoryInterface $repo, PackageInterface $package, $bucket = array())
     {
diff --git a/src/Composer/Command/SelfUpdateCommand.php b/src/Composer/Command/SelfUpdateCommand.php
index 2ba0cedfb..986b26662 100644
--- a/src/Composer/Command/SelfUpdateCommand.php
+++ b/src/Composer/Command/SelfUpdateCommand.php
@@ -305,6 +305,8 @@ TAGSPUBKEY
      * @param string $localFilename
      * @param string $newFilename
      * @param string $backupTarget
+     * @return \Exception|null
+     * @throws \Exception
      */
     protected function setLocalPhar($localFilename, $newFilename, $backupTarget = null)
     {
@@ -323,6 +325,7 @@ TAGSPUBKEY
             }
 
             rename($newFilename, $localFilename);
+            return null;
         } catch (\Exception $e) {
             if (!$e instanceof \UnexpectedValueException && !$e instanceof \PharException) {
                 throw $e;
diff --git a/src/Composer/Command/ShowCommand.php b/src/Composer/Command/ShowCommand.php
index fbc704d61..df9e5e944 100644
--- a/src/Composer/Command/ShowCommand.php
+++ b/src/Composer/Command/ShowCommand.php
@@ -332,7 +332,11 @@ EOT
     }
 
     /**
-     * prints package meta data
+     * Prints package metadata.
+     *
+     * @param CompletePackageInterface $package
+     * @param array                    $versions
+     * @param RepositoryInterface      $installedRepo
      */
     protected function printMeta(CompletePackageInterface $package, array $versions, RepositoryInterface $installedRepo)
     {
@@ -389,7 +393,11 @@ EOT
     }
 
     /**
-     * prints all available versions of this package and highlights the installed one if any
+     * Prints all available versions of this package and highlights the installed one if any.
+     *
+     * @param CompletePackageInterface $package
+     * @param array                    $versions
+     * @param RepositoryInterface      $installedRepo
      */
     protected function printVersions(CompletePackageInterface $package, array $versions, RepositoryInterface $installedRepo)
     {
diff --git a/src/Composer/DependencyResolver/Request.php b/src/Composer/DependencyResolver/Request.php
index 7eacdf1f6..d5c47954b 100644
--- a/src/Composer/DependencyResolver/Request.php
+++ b/src/Composer/DependencyResolver/Request.php
@@ -45,6 +45,9 @@ class Request
      * Mark an existing package as being installed and having to remain installed
      *
      * These jobs will not be tempered with by the solver
+     *
+     * @param string                    $packageName
+     * @param ConstraintInterface|null  $constraint
      */
     public function fix($packageName, ConstraintInterface $constraint = null)
     {
diff --git a/src/Composer/EventDispatcher/EventDispatcher.php b/src/Composer/EventDispatcher/EventDispatcher.php
index 70a370722..a4c9d3061 100644
--- a/src/Composer/EventDispatcher/EventDispatcher.php
+++ b/src/Composer/EventDispatcher/EventDispatcher.php
@@ -137,11 +137,9 @@ class EventDispatcher
      * Triggers the listeners of an event.
      *
      * @param  Event             $event          The event object to pass to the event handlers/listeners.
-     * @param  string            $additionalArgs
-     * @throws \RuntimeException
-     * @throws \Exception
      * @return int               return code of the executed script if any, for php scripts a false return
      *                                          value is changed to 1, anything else to 0
+     * @throws \RuntimeException|\Exception
      */
     protected function doDispatch(Event $event)
     {
diff --git a/src/Composer/IO/BufferIO.php b/src/Composer/IO/BufferIO.php
index 1069c0d9a..d47d4eaa5 100644
--- a/src/Composer/IO/BufferIO.php
+++ b/src/Composer/IO/BufferIO.php
@@ -23,15 +23,12 @@ use Symfony\Component\Console\Helper\HelperSet;
 class BufferIO extends ConsoleIO
 {
     /**
-     * @param string                   $input
-     * @param int                      $verbosity
-     * @param OutputFormatterInterface $formatter
+     * @param string                        $input
+     * @param int                           $verbosity
+     * @param OutputFormatterInterface|null $formatter
      */
-    public function __construct(
-        $input = '',
-        $verbosity = StreamOutput::VERBOSITY_NORMAL,
-        OutputFormatterInterface $formatter = null
-    ) {
+    public function __construct($input = '', $verbosity = StreamOutput::VERBOSITY_NORMAL, OutputFormatterInterface $formatter = null)
+    {
         $input = new StringInput($input);
         $input->setInteractive(false);
 
diff --git a/src/Composer/Installer/PearBinaryInstaller.php b/src/Composer/Installer/PearBinaryInstaller.php
index 222b880b2..752068ca2 100644
--- a/src/Composer/Installer/PearBinaryInstaller.php
+++ b/src/Composer/Installer/PearBinaryInstaller.php
@@ -30,10 +30,12 @@ class PearBinaryInstaller extends BinaryInstaller
     private $vendorDir;
 
     /**
-     * @param IOInterface $io
-     * @param string $binDir
-     * @param string $binCompat
-     * @param Filesystem $filesystem
+     * @param IOInterface   $io
+     * @param string        $binDir
+     * @param string        $vendorDir
+     * @param string        $binCompat
+     * @param Filesystem    $filesystem
+     * @param PearInstaller $installer
      */
     public function __construct(IOInterface $io, $binDir, $vendorDir, $binCompat, Filesystem $filesystem, PearInstaller $installer)
     {
diff --git a/src/Composer/Installer/SuggestedPackagesReporter.php b/src/Composer/Installer/SuggestedPackagesReporter.php
index d56628ceb..777ab1330 100644
--- a/src/Composer/Installer/SuggestedPackagesReporter.php
+++ b/src/Composer/Installer/SuggestedPackagesReporter.php
@@ -29,7 +29,7 @@ class SuggestedPackagesReporter
     protected $suggestedPackages = array();
 
     /**
-     * @var Composer\IO\IOInterface
+     * @var \Composer\IO\IOInterface
      */
     private $io;
 
diff --git a/src/Composer/Json/JsonFile.php b/src/Composer/Json/JsonFile.php
index 4a6eb89ca..2a59e592f 100644
--- a/src/Composer/Json/JsonFile.php
+++ b/src/Composer/Json/JsonFile.php
@@ -43,6 +43,7 @@ class JsonFile
      *
      * @param  string                    $path path to a lockfile
      * @param  RemoteFilesystem          $rfs  required for loading http/https json files
+     * @param  IOInterface               $io
      * @throws \InvalidArgumentException
      */
     public function __construct($path, RemoteFilesystem $rfs = null, IOInterface $io = null)
@@ -105,7 +106,7 @@ class JsonFile
      *
      * @param  array                     $hash    writes hash into json file
      * @param  int                       $options json_encode options (defaults to JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE)
-     * @throws \UnexpectedValueException
+     * @throws \UnexpectedValueException|\Exception
      */
     public function write(array $hash, $options = 448)
     {
diff --git a/src/Composer/Repository/ComposerRepository.php b/src/Composer/Repository/ComposerRepository.php
index 035c2b0d7..fd55610ae 100644
--- a/src/Composer/Repository/ComposerRepository.php
+++ b/src/Composer/Repository/ComposerRepository.php
@@ -272,6 +272,7 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
      * @param Pool   $pool
      * @param string $name package name
      * @param bool   $bypassFilters If set to true, this bypasses the stability filtering, and forces a recompute without cache
+     * @return array|mixed
      */
     public function whatProvides(Pool $pool, $name, $bypassFilters = false)
     {
diff --git a/src/Composer/Repository/RepositoryFactory.php b/src/Composer/Repository/RepositoryFactory.php
index 681e3bfee..08146546f 100644
--- a/src/Composer/Repository/RepositoryFactory.php
+++ b/src/Composer/Repository/RepositoryFactory.php
@@ -25,7 +25,11 @@ use Composer\Json\JsonFile;
 class RepositoryFactory
 {
     /**
-     * @return array
+     * @param IOInterface   $io
+     * @param Config        $config
+     * @param string        $repository
+     * @param bool          $allowFilesystem
+     * @return array|mixed
      */
     public static function configFromString(IOInterface $io, Config $config, $repository, $allowFilesystem = false)
     {
@@ -52,6 +56,10 @@ class RepositoryFactory
     }
 
     /**
+     * @param IOInterface   $io
+     * @param Config        $config
+     * @param string        $repository
+     * @param bool          $allowFilesystem
      * @return RepositoryInterface
      */
     public static function fromString(IOInterface $io, Config $config, $repository, $allowFilesystem = false)