diff --git a/src/Composer/Command/AboutCommand.php b/src/Composer/Command/AboutCommand.php
index 931c20e55..38ac0f226 100644
--- a/src/Composer/Command/AboutCommand.php
+++ b/src/Composer/Command/AboutCommand.php
@@ -21,6 +21,9 @@ use Symfony\Component\Console\Output\OutputInterface;
  */
 class AboutCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
diff --git a/src/Composer/Command/ArchiveCommand.php b/src/Composer/Command/ArchiveCommand.php
index 57d99e3aa..c30c2364d 100644
--- a/src/Composer/Command/ArchiveCommand.php
+++ b/src/Composer/Command/ArchiveCommand.php
@@ -38,6 +38,9 @@ use Symfony\Component\Console\Output\OutputInterface;
  */
 class ArchiveCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -110,7 +113,15 @@ EOT
     }
 
     /**
+     * @param string|null $packageName
+     * @param string|null $version
+     * @param string $format
+     * @param string $dest
+     * @param string|null $fileName
+     * @param bool $ignoreFilters
+     *
      * @return int
+     * @throws \Exception
      */
     protected function archive(IOInterface $io, Config $config, $packageName = null, $version = null, $format = 'tar', $dest = '.', $fileName = null, $ignoreFilters = false, Composer $composer = null)
     {
@@ -146,6 +157,9 @@ EOT
     }
 
     /**
+     * @param string      $packageName
+     * @param string|null $version
+     *
      * @return (BasePackage&CompletePackageInterface)|false
      */
     protected function selectPackage(IOInterface $io, $packageName, $version = null)
diff --git a/src/Composer/Command/BaseCommand.php b/src/Composer/Command/BaseCommand.php
index b473fbe80..022d7e77b 100644
--- a/src/Composer/Command/BaseCommand.php
+++ b/src/Composer/Command/BaseCommand.php
@@ -23,6 +23,7 @@ use Composer\Package\Version\VersionParser;
 use Composer\Plugin\PluginEvents;
 use Composer\Util\Platform;
 use Symfony\Component\Console\Helper\Table;
+use Symfony\Component\Console\Helper\TableSeparator;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\Console\Command\Command;
@@ -74,7 +75,7 @@ abstract class BaseCommand extends Command
     }
 
     /**
-     * @param Composer $composer
+     * @return void
      */
     public function setComposer(Composer $composer)
     {
@@ -83,6 +84,8 @@ abstract class BaseCommand extends Command
 
     /**
      * Removes the cached composer instance
+     *
+     * @return void
      */
     public function resetComposer()
     {
@@ -121,7 +124,7 @@ abstract class BaseCommand extends Command
     }
 
     /**
-     * @param IOInterface $io
+     * @return void
      */
     public function setIO(IOInterface $io)
     {
@@ -130,6 +133,8 @@ abstract class BaseCommand extends Command
 
     /**
      * {@inheritDoc}
+     *
+     * @return void
      */
     protected function initialize(InputInterface $input, OutputInterface $output)
     {
@@ -154,8 +159,6 @@ abstract class BaseCommand extends Command
     /**
      * Returns preferSource and preferDist values based on the configuration.
      *
-     * @param Config         $config
-     * @param InputInterface $input
      * @param bool           $keepVcsRequiresPreferSource
      *
      * @return bool[] An array composed of the preferSource and preferDist values
@@ -209,6 +212,11 @@ abstract class BaseCommand extends Command
         return array($preferSource, $preferDist);
     }
 
+    /**
+     * @param array<string, string> $requirements
+     *
+     * @return array<string, string>
+     */
     protected function formatRequirements(array $requirements)
     {
         $requires = array();
@@ -223,6 +231,11 @@ abstract class BaseCommand extends Command
         return $requires;
     }
 
+    /**
+     * @param array<string> $requirements
+     *
+     * @return list<array{name: string, version?: string}>
+     */
     protected function normalizeRequirements(array $requirements)
     {
         $parser = new VersionParser();
@@ -230,6 +243,11 @@ abstract class BaseCommand extends Command
         return $parser->parseNameVersionPairs($requirements);
     }
 
+    /**
+     * @param array<TableSeparator|array> $table
+     *
+     * @return void
+     */
     protected function renderTable(array $table, OutputInterface $output)
     {
         $renderer = new Table($output);
@@ -246,6 +264,9 @@ abstract class BaseCommand extends Command
         $renderer->setRows($table)->render();
     }
 
+    /**
+     * @return int
+     */
     protected function getTerminalWidth()
     {
         if (class_exists('Symfony\Component\Console\Terminal')) {
diff --git a/src/Composer/Command/BaseDependencyCommand.php b/src/Composer/Command/BaseDependencyCommand.php
index b49a76b7d..ae91abae6 100644
--- a/src/Composer/Command/BaseDependencyCommand.php
+++ b/src/Composer/Command/BaseDependencyCommand.php
@@ -47,8 +47,6 @@ class BaseDependencyCommand extends BaseCommand
     /**
      * Execute the command.
      *
-     * @param  InputInterface  $input
-     * @param  OutputInterface $output
      * @param  bool            $inverted Whether to invert matching process (why-not vs why behaviour)
      * @return int             Exit code of the operation.
      */
@@ -134,8 +132,9 @@ class BaseDependencyCommand extends BaseCommand
     /**
      * Assembles and prints a bottom-up table of the dependencies.
      *
-     * @param OutputInterface $output
-     * @param array           $results
+     * @param array[]         $results
+     *
+     * @return void
      */
     protected function printTable(OutputInterface $output, $results)
     {
@@ -171,7 +170,7 @@ class BaseDependencyCommand extends BaseCommand
     /**
      * Init styles for tree
      *
-     * @param OutputInterface $output
+     * @return void
      */
     protected function initStyles(OutputInterface $output)
     {
@@ -192,9 +191,11 @@ class BaseDependencyCommand extends BaseCommand
     /**
      * Recursively prints a tree of the selected results.
      *
-     * @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.
+     * @param array[] $results Results to be printed at this level.
+     * @param string  $prefix  Prefix of the current tree level.
+     * @param int     $level   Current level of recursion.
+     *
+     * @return void
      */
     protected function printTree($results, $prefix = '', $level = 1)
     {
@@ -222,6 +223,11 @@ class BaseDependencyCommand extends BaseCommand
         }
     }
 
+    /**
+     * @param string $line
+     *
+     * @return void
+     */
     private function writeTreeLine($line)
     {
         $io = $this->getIO();
diff --git a/src/Composer/Command/CheckPlatformReqsCommand.php b/src/Composer/Command/CheckPlatformReqsCommand.php
index 2f68a65cb..170e25f29 100644
--- a/src/Composer/Command/CheckPlatformReqsCommand.php
+++ b/src/Composer/Command/CheckPlatformReqsCommand.php
@@ -23,6 +23,9 @@ use Composer\Repository\InstalledRepository;
 
 class CheckPlatformReqsCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this->setName('check-platform-reqs')
@@ -43,6 +46,9 @@ EOT
             );
     }
 
+    /**
+     * @return int
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $composer = $this->getComposer();
@@ -166,6 +172,11 @@ EOT
         return $exitCode;
     }
 
+    /**
+     * @param array[] $results
+     *
+     * @return void
+     */
     protected function printTable(OutputInterface $output, $results)
     {
         $rows = array();
diff --git a/src/Composer/Command/ClearCacheCommand.php b/src/Composer/Command/ClearCacheCommand.php
index bdbdd80cf..51e02b789 100644
--- a/src/Composer/Command/ClearCacheCommand.php
+++ b/src/Composer/Command/ClearCacheCommand.php
@@ -22,6 +22,9 @@ use Symfony\Component\Console\Output\OutputInterface;
  */
 class ClearCacheCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -39,6 +42,9 @@ EOT
         ;
     }
 
+    /**
+     * @return int
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $config = Factory::createConfig();
diff --git a/src/Composer/Command/ConfigCommand.php b/src/Composer/Command/ConfigCommand.php
index c96597dce..4f486cc83 100644
--- a/src/Composer/Command/ConfigCommand.php
+++ b/src/Composer/Command/ConfigCommand.php
@@ -58,6 +58,9 @@ class ConfigCommand extends BaseCommand
      */
     protected $authConfigSource;
 
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -145,6 +148,10 @@ EOT
         ;
     }
 
+    /**
+     * @return void
+     * @throws \Exception
+     */
     protected function initialize(InputInterface $input, OutputInterface $output)
     {
         parent::initialize($input, $output);
@@ -198,6 +205,10 @@ EOT
         }
     }
 
+    /**
+     * @return int
+     * @throws \Seld\JsonLint\ParsingException
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         // Open file in editor
@@ -750,6 +761,14 @@ EOT
         throw new \InvalidArgumentException('Setting '.$settingKey.' does not exist or is not supported by this command');
     }
 
+    /**
+     * @param string $key
+     * @param array{callable, callable} $callbacks Validator and normalizer callbacks
+     * @param array<string> $values
+     * @param string $method
+     *
+     * @return void
+     */
     protected function handleSingleValue($key, array $callbacks, array $values, $method)
     {
         list($validator, $normalizer) = $callbacks;
@@ -774,9 +793,17 @@ EOT
             }
         }
 
-        return call_user_func(array($this->configSource, $method), $key, $normalizedValue);
+        call_user_func(array($this->configSource, $method), $key, $normalizedValue);
     }
 
+    /**
+     * @param string $key
+     * @param array{callable, callable} $callbacks Validator and normalizer callbacks
+     * @param array<string> $values
+     * @param string $method
+     *
+     * @return void
+     */
     protected function handleMultiValue($key, array $callbacks, array $values, $method)
     {
         list($validator, $normalizer) = $callbacks;
@@ -787,16 +814,17 @@ EOT
             ));
         }
 
-        return call_user_func(array($this->configSource, $method), $key, $normalizer($values));
+        call_user_func(array($this->configSource, $method), $key, $normalizer($values));
     }
 
     /**
      * Display the contents of the file in a pretty formatted way
      *
-     * @param array           $contents
-     * @param array           $rawContents
-     * @param OutputInterface $output
-     * @param string|null     $k
+     * @param array<array|bool|string> $contents
+     * @param array<array|string>      $rawContents
+     * @param string|null              $k
+     *
+     * @return void
      */
     protected function listConfiguration(array $contents, array $rawContents, OutputInterface $output, $k = null)
     {
diff --git a/src/Composer/Command/CreateProjectCommand.php b/src/Composer/Command/CreateProjectCommand.php
index e47945466..da01080f6 100644
--- a/src/Composer/Command/CreateProjectCommand.php
+++ b/src/Composer/Command/CreateProjectCommand.php
@@ -56,6 +56,9 @@ class CreateProjectCommand extends BaseCommand
      */
     protected $suggestedPackagesReporter;
 
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -115,6 +118,9 @@ EOT
         ;
     }
 
+    /**
+     * @return int
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $config = Factory::createConfig();
@@ -160,9 +166,26 @@ EOT
     }
 
     /**
+     * @param string|null $packageName
+     * @param string|null $directory
+     * @param string|null $packageVersion
+     * @param string $stability
+     * @param bool $preferSource
+     * @param bool $preferDist
+     * @param bool $installDevPackages
+     * @param string|array<string>|null $repositories
+     * @param bool $disablePlugins
+     * @param bool $noScripts
+     * @param bool $noProgress
+     * @param bool $noInstall
+     * @param bool $ignorePlatformReqs
+     * @param bool $secureHttp
+     * @param bool $addRepository
+     *
      * @return int
+     * @throws \Exception
      */
-    public function installProject(IOInterface $io, Config $config, InputInterface $input, $packageName, $directory = null, $packageVersion = null, $stability = 'stable', $preferSource = false, $preferDist = false, $installDevPackages = false, $repositories = null, $disablePlugins = false, $noScripts = false, $noProgress = false, $noInstall = false, $ignorePlatformReqs = false, $secureHttp = true, $addRepository = false)
+    public function installProject(IOInterface $io, Config $config, InputInterface $input, $packageName = null, $directory = null, $packageVersion = null, $stability = 'stable', $preferSource = false, $preferDist = false, $installDevPackages = false, $repositories = null, $disablePlugins = false, $noScripts = false, $noProgress = false, $noInstall = false, $ignorePlatformReqs = false, $secureHttp = true, $addRepository = false)
     {
         $oldCwd = getcwd();
 
@@ -308,7 +331,22 @@ EOT
     }
 
     /**
+     * @param string $packageName
+     * @param string|null $directory
+     * @param string|null $packageVersion
+     * @param string|null $stability
+     * @param bool $preferSource
+     * @param bool $preferDist
+     * @param bool $installDevPackages
+     * @param array<string>|null $repositories
+     * @param bool $disablePlugins
+     * @param bool $noScripts
+     * @param bool $noProgress
+     * @param bool $ignorePlatformReqs
+     * @param bool $secureHttp
+     *
      * @return bool
+     * @throws \Exception
      */
     protected function installRootPackage(IOInterface $io, Config $config, $packageName, $directory = null, $packageVersion = null, $stability = 'stable', $preferSource = false, $preferDist = false, $installDevPackages = false, array $repositories = null, $disablePlugins = false, $noScripts = false, $noProgress = false, $ignorePlatformReqs = false, $secureHttp = true)
     {
diff --git a/src/Composer/Command/DependsCommand.php b/src/Composer/Command/DependsCommand.php
index c1ebe7eab..9ea939946 100644
--- a/src/Composer/Command/DependsCommand.php
+++ b/src/Composer/Command/DependsCommand.php
@@ -24,6 +24,8 @@ class DependsCommand extends BaseDependencyCommand
 {
     /**
      * Configure command metadata.
+     *
+     * @return void
      */
     protected function configure()
     {
@@ -51,8 +53,6 @@ EOT
     /**
      * Execute the function.
      *
-     * @param  InputInterface  $input
-     * @param  OutputInterface $output
      * @return int
      */
     protected function execute(InputInterface $input, OutputInterface $output)
diff --git a/src/Composer/Command/DiagnoseCommand.php b/src/Composer/Command/DiagnoseCommand.php
index b788c5e0f..8e4e617cc 100644
--- a/src/Composer/Command/DiagnoseCommand.php
+++ b/src/Composer/Command/DiagnoseCommand.php
@@ -48,6 +48,9 @@ class DiagnoseCommand extends BaseCommand
     /** @var int */
     protected $exitCode = 0;
 
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -65,6 +68,9 @@ EOT
         ;
     }
 
+    /**
+     * @return int
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $composer = $this->getComposer(false);
@@ -237,6 +243,8 @@ EOT
     }
 
     /**
+     * @param string $proto
+     *
      * @return string|string[]|true
      */
     private function checkHttp($proto, Config $config)
@@ -303,6 +311,9 @@ EOT
     }
 
     /**
+     * @param string $domain
+     * @param string $token
+     *
      * @return string|true|\Exception
      */
     private function checkGithubOauth($domain, $token)
@@ -356,7 +367,7 @@ EOT
     /**
      * @return string|true
      */
-    private function checkDiskSpace($config)
+    private function checkDiskSpace(Config $config)
     {
         $minSpaceFree = 1024 * 1024;
         if ((($df = @disk_free_space($dir = $config->get('home'))) !== false && $df < $minSpaceFree)
@@ -371,7 +382,7 @@ EOT
     /**
      * @return string[]|true
      */
-    private function checkPubKeys($config)
+    private function checkPubKeys(Config $config)
     {
         $home = $config->get('home');
         $errors = array();
@@ -403,7 +414,7 @@ EOT
     /**
      * @return string|\Exception|true
      */
-    private function checkVersion($config)
+    private function checkVersion(Config $config)
     {
         $result = $this->checkConnectivity();
         if ($result !== true) {
@@ -446,6 +457,8 @@ EOT
 
     /**
      * @param bool|string|string[]|\Exception $result
+     *
+     * @return void
      */
     private function outputResult($result)
     {
diff --git a/src/Composer/Command/DumpAutoloadCommand.php b/src/Composer/Command/DumpAutoloadCommand.php
index c4b0b9926..20da6fb15 100644
--- a/src/Composer/Command/DumpAutoloadCommand.php
+++ b/src/Composer/Command/DumpAutoloadCommand.php
@@ -23,6 +23,9 @@ use Symfony\Component\Console\Output\OutputInterface;
  */
 class DumpAutoloadCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -50,6 +53,9 @@ EOT
         ;
     }
 
+    /**
+     * @return int
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $composer = $this->getComposer();
diff --git a/src/Composer/Command/ExecCommand.php b/src/Composer/Command/ExecCommand.php
index 167a2be0d..7cc2c3fae 100644
--- a/src/Composer/Command/ExecCommand.php
+++ b/src/Composer/Command/ExecCommand.php
@@ -22,6 +22,9 @@ use Symfony\Component\Console\Input\InputArgument;
  */
 class ExecCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -46,6 +49,9 @@ EOT
         ;
     }
 
+    /**
+     * @return int
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $composer = $this->getComposer();
diff --git a/src/Composer/Command/FundCommand.php b/src/Composer/Command/FundCommand.php
index edba9e806..00bbca4af 100644
--- a/src/Composer/Command/FundCommand.php
+++ b/src/Composer/Command/FundCommand.php
@@ -28,6 +28,9 @@ use Symfony\Component\Console\Output\OutputInterface;
  */
 class FundCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this->setName('fund')
@@ -38,6 +41,9 @@ class FundCommand extends BaseCommand
         ;
     }
 
+    /**
+     * @return int
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $composer = $this->getComposer();
@@ -125,6 +131,10 @@ class FundCommand extends BaseCommand
         return 0;
     }
 
+    /**
+     * @param array[] $fundings
+     * @return array[]
+     */
     private function insertFundingData(array $fundings, CompletePackageInterface $package)
     {
         foreach ($package->getFunding() as $fundingOption) {
diff --git a/src/Composer/Command/GlobalCommand.php b/src/Composer/Command/GlobalCommand.php
index c78ea7109..b35393a90 100644
--- a/src/Composer/Command/GlobalCommand.php
+++ b/src/Composer/Command/GlobalCommand.php
@@ -25,6 +25,9 @@ use Symfony\Component\Console\Output\OutputInterface;
  */
 class GlobalCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -57,6 +60,10 @@ EOT
         ;
     }
 
+    /**
+     * @return int|void
+     * @throws \Symfony\Component\Console\Exception\ExceptionInterface
+     */
     public function run(InputInterface $input, OutputInterface $output)
     {
         if (!method_exists($input, '__toString')) {
diff --git a/src/Composer/Command/HomeCommand.php b/src/Composer/Command/HomeCommand.php
index 62c52e923..540f2bc4c 100644
--- a/src/Composer/Command/HomeCommand.php
+++ b/src/Composer/Command/HomeCommand.php
@@ -30,6 +30,8 @@ class HomeCommand extends BaseCommand
 {
     /**
      * {@inheritDoc}
+     *
+     * @return void
      */
     protected function configure()
     {
@@ -98,6 +100,8 @@ EOT
     }
 
     /**
+     * @param bool $showHomepage
+     * @param bool $showOnly
      * @return bool
      */
     private function handlePackage(CompletePackageInterface $package, $showHomepage, $showOnly)
diff --git a/src/Composer/Command/InitCommand.php b/src/Composer/Command/InitCommand.php
index e06b670b9..945571441 100644
--- a/src/Composer/Command/InitCommand.php
+++ b/src/Composer/Command/InitCommand.php
@@ -54,6 +54,8 @@ class InitCommand extends BaseCommand
 
     /**
      * {@inheritdoc}
+     *
+     * @return void
      */
     protected function configure()
     {
@@ -89,6 +91,9 @@ EOT
 
     /**
      * {@inheritdoc}
+     *
+     * @return int
+     * @throws \Seld\JsonLint\ParsingException
      */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
@@ -220,6 +225,8 @@ EOT
 
     /**
      * {@inheritdoc}
+     *
+     * @return void
      */
     protected function interact(InputInterface $input, OutputInterface $output)
     {
@@ -480,6 +487,10 @@ EOT
         );
     }
 
+    /**
+     * @param string $name
+     * @return list<array{name: string, description: ?string}>
+     */
     protected function findPackages($name)
     {
         return $this->getRepos()->search($name);
@@ -500,6 +511,16 @@ EOT
         return $this->repos;
     }
 
+    /**
+     * @param array<string> $requires
+     * @param PlatformRepository|null $platformRepo
+     * @param string $preferredStability
+     * @param bool $checkProvidedVersions
+     * @param bool $fixed
+     *
+     * @return array<string>
+     * @throws \Exception
+     */
     final protected function determineRequirements(InputInterface $input, OutputInterface $output, $requires = array(), PlatformRepository $platformRepo = null, $preferredStability = 'stable', $checkProvidedVersions = true, $fixed = false)
     {
         if ($requires) {
@@ -667,6 +688,8 @@ EOT
     }
 
     /**
+     * @param string $author
+     *
      * @return array<int, array{name: string, email: string}>
      */
     protected function formatAuthors($author)
@@ -702,6 +725,9 @@ EOT
         return join('\\', $namespace);
     }
 
+    /**
+     * @return array<string, string>
+     */
     protected function getGitConfig()
     {
         if (null !== $this->gitConfig) {
@@ -767,6 +793,12 @@ EOT
         return false;
     }
 
+    /**
+     * @param string $ignoreFile
+     * @param string $vendor
+     *
+     * @return void
+     */
     protected function addVendorIgnore($ignoreFile, $vendor = '/vendor/')
     {
         $contents = "";
@@ -782,6 +814,8 @@ EOT
     }
 
     /**
+     * @param string $email
+     *
      * @return bool
      */
     protected function isValidEmail($email)
@@ -800,6 +834,8 @@ EOT
     }
 
     /**
+     * @param string|null $minimumStability
+     *
      * @return RepositorySet
      */
     private function getRepositorySet(InputInterface $input, $minimumStability = null)
@@ -838,7 +874,6 @@ EOT
      *
      * This returns a version with the ~ operator prefixed when possible.
      *
-     * @param  InputInterface            $input
      * @param  string                    $name
      * @param  PlatformRepository|null   $platformRepo
      * @param  string                    $preferredStability
@@ -846,7 +881,7 @@ EOT
      * @param  string                    $minimumStability
      * @param  bool                      $fixed
      * @throws \InvalidArgumentException
-     * @return array                     name version
+     * @return array{string, string}     name version
      */
     private function findBestVersionAndNameForPackage(InputInterface $input, $name, PlatformRepository $platformRepo = null, $preferredStability = 'stable', $requiredVersion = null, $minimumStability = null, $fixed = null)
     {
@@ -987,6 +1022,11 @@ EOT
         return ':'.PHP_EOL.'  - ' . implode(PHP_EOL.'  - ', $details);
     }
 
+    /**
+     * @param string $package
+     *
+     * @return array<string>
+     */
     private function findSimilar($package)
     {
         try {
@@ -1014,7 +1054,7 @@ EOT
     /**
      * @return void
      */
-    private function updateDependencies($output)
+    private function updateDependencies(OutputInterface $output)
     {
         try {
             $updateCommand = $this->getApplication()->find('update');
@@ -1028,7 +1068,7 @@ EOT
     /**
      * @return void
      */
-    private function runDumpAutoloadCommand($output)
+    private function runDumpAutoloadCommand(OutputInterface $output)
     {
         try {
             $command = $this->getApplication()->find('dump-autoload');
@@ -1040,6 +1080,7 @@ EOT
     }
 
     /**
+     * @param array<string, string|array<string>> $options
      * @return bool
      */
     private function hasDependencies($options)
diff --git a/src/Composer/Command/InstallCommand.php b/src/Composer/Command/InstallCommand.php
index eda9c25cf..583fc33a1 100644
--- a/src/Composer/Command/InstallCommand.php
+++ b/src/Composer/Command/InstallCommand.php
@@ -29,6 +29,9 @@ use Symfony\Component\Console\Output\OutputInterface;
  */
 class InstallCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
diff --git a/src/Composer/Command/LicensesCommand.php b/src/Composer/Command/LicensesCommand.php
index b4544cf50..3f19d366e 100644
--- a/src/Composer/Command/LicensesCommand.php
+++ b/src/Composer/Command/LicensesCommand.php
@@ -13,6 +13,8 @@
 namespace Composer\Command;
 
 use Composer\Json\JsonFile;
+use Composer\Package\BasePackage;
+use Composer\Package\CompletePackageInterface;
 use Composer\Plugin\CommandEvent;
 use Composer\Plugin\PluginEvents;
 use Composer\Package\PackageInterface;
@@ -28,6 +30,9 @@ use Symfony\Component\Console\Style\SymfonyStyle;
  */
 class LicensesCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -48,6 +53,9 @@ EOT
         ;
     }
 
+    /**
+     * @return int
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $composer = $this->getComposer();
@@ -91,7 +99,7 @@ EOT
                     $table->addRow(array(
                         $package->getPrettyName(),
                         $package->getFullPrettyVersion(),
-                        implode(', ', $package->getLicense()) ?: 'none',
+                        implode(', ', $package instanceof CompletePackageInterface ? $package->getLicense() : array()) ?: 'none',
                     ));
                 }
                 $table->render();
@@ -102,7 +110,7 @@ EOT
                 foreach ($packages as $package) {
                     $dependencies[$package->getPrettyName()] = array(
                         'version' => $package->getFullPrettyVersion(),
-                        'license' => $package->getLicense(),
+                        'license' => $package instanceof CompletePackageInterface ? $package->getLicense() : array(),
                     );
                 }
 
@@ -117,7 +125,7 @@ EOT
             case 'summary':
                 $usedLicenses = array();
                 foreach ($packages as $package) {
-                    $license = $package->getLicense();
+                    $license = $package instanceof CompletePackageInterface ? $package->getLicense() : array();
                     $licenseName = $license[0];
                     if (!isset($usedLicenses[$licenseName])) {
                         $usedLicenses[$licenseName] = 0;
@@ -149,10 +157,8 @@ EOT
     /**
      * Find package requires and child requires
      *
-     * @param  RepositoryInterface $repo
-     * @param  PackageInterface    $package
-     * @param  array               $bucket
-     * @return array
+     * @param  array<string, PackageInterface> $bucket
+     * @return array<string, PackageInterface>
      */
     private function filterRequiredPackages(RepositoryInterface $repo, PackageInterface $package, $bucket = array())
     {
@@ -178,9 +184,9 @@ EOT
     /**
      * Adds packages to the package list
      *
-     * @param  array $packages the list of packages to add
-     * @param  array $bucket   the list to add packages to
-     * @return array
+     * @param  PackageInterface[]              $packages the list of packages to add
+     * @param  array<string, PackageInterface> $bucket   the list to add packages to
+     * @return array<string, PackageInterface>
      */
     public function appendPackages(array $packages, array $bucket)
     {
diff --git a/src/Composer/Command/OutdatedCommand.php b/src/Composer/Command/OutdatedCommand.php
index ace1631d8..584a755b7 100644
--- a/src/Composer/Command/OutdatedCommand.php
+++ b/src/Composer/Command/OutdatedCommand.php
@@ -23,6 +23,9 @@ use Symfony\Component\Console\Output\OutputInterface;
  */
 class OutdatedCommand extends ShowCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
diff --git a/src/Composer/Command/ProhibitsCommand.php b/src/Composer/Command/ProhibitsCommand.php
index 9931a881b..c51d320f5 100644
--- a/src/Composer/Command/ProhibitsCommand.php
+++ b/src/Composer/Command/ProhibitsCommand.php
@@ -24,6 +24,8 @@ class ProhibitsCommand extends BaseDependencyCommand
 {
     /**
      * Configure command metadata.
+     *
+     * @return void
      */
     protected function configure()
     {
@@ -52,8 +54,6 @@ EOT
     /**
      * Execute the function.
      *
-     * @param  InputInterface  $input
-     * @param  OutputInterface $output
      * @return int
      */
     protected function execute(InputInterface $input, OutputInterface $output)
diff --git a/src/Composer/Command/ReinstallCommand.php b/src/Composer/Command/ReinstallCommand.php
index c92564658..94da95f1d 100644
--- a/src/Composer/Command/ReinstallCommand.php
+++ b/src/Composer/Command/ReinstallCommand.php
@@ -29,6 +29,9 @@ use Symfony\Component\Console\Output\OutputInterface;
  */
 class ReinstallCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
diff --git a/src/Composer/Command/RemoveCommand.php b/src/Composer/Command/RemoveCommand.php
index 3cd865126..926500c09 100644
--- a/src/Composer/Command/RemoveCommand.php
+++ b/src/Composer/Command/RemoveCommand.php
@@ -31,6 +31,9 @@ use Composer\Package\BasePackage;
  */
 class RemoveCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -70,6 +73,9 @@ EOT
         ;
     }
 
+    /**
+     * @return void
+     */
     protected function interact(InputInterface $input, OutputInterface $output)
     {
         if ($input->getOption('unused')) {
@@ -117,6 +123,10 @@ EOT
         }
     }
 
+    /**
+     * @return int
+     * @throws \Seld\JsonLint\ParsingException
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $packages = $input->getArgument('packages');
diff --git a/src/Composer/Command/RequireCommand.php b/src/Composer/Command/RequireCommand.php
index 9388af63d..c629af5db 100644
--- a/src/Composer/Command/RequireCommand.php
+++ b/src/Composer/Command/RequireCommand.php
@@ -56,6 +56,9 @@ class RequireCommand extends InitCommand
     /** @var bool */
     private $dependencyResolutionCompleted = false;
 
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -106,6 +109,10 @@ EOT
         ;
     }
 
+    /**
+     * @return int
+     * @throws \Seld\JsonLint\ParsingException
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         if (function_exists('pcntl_async_signals') && function_exists('pcntl_signal')) {
@@ -280,6 +287,11 @@ EOT
         }
     }
 
+    /**
+     * @param array<string, string> $newRequirements
+     * @param string $requireKey
+     * @return string[]
+     */
     private function getInconsistentRequireKeys(array $newRequirements, $requireKey)
     {
         $requireKeys = $this->getPackagesByRequireKey();
@@ -296,6 +308,9 @@ EOT
         return $inconsistentRequirements;
     }
 
+    /**
+     * @return array<string, string>
+     */
     private function getPackagesByRequireKey()
     {
         $composerDefinition = $this->json->read();
@@ -318,12 +333,20 @@ EOT
 
     /**
      * @private
+     * @return void
      */
     public function markSolverComplete()
     {
         $this->dependencyResolutionCompleted = true;
     }
 
+    /**
+     * @param array<string, string> $requirements
+     * @param string $requireKey
+     * @param string $removeKey
+     * @return int
+     * @throws \Exception
+     */
     private function doUpdate(InputInterface $input, OutputInterface $output, IOInterface $io, array $requirements, $requireKey, $removeKey)
     {
         // Update packages
@@ -418,9 +441,13 @@ EOT
     }
 
     /**
+     * @param array<string, string> $new
+     * @param string $requireKey
+     * @param string $removeKey
+     * @param bool $sortPackages
      * @return bool
      */
-    private function updateFileCleanly($json, array $new, $requireKey, $removeKey, $sortPackages)
+    private function updateFileCleanly(JsonFile $json, array $new, $requireKey, $removeKey, $sortPackages)
     {
         $contents = file_get_contents($json->getPath());
 
@@ -447,6 +474,10 @@ EOT
         return;
     }
 
+    /**
+     * @param bool $hardExit
+     * @return void
+     */
     public function revertComposerFile($hardExit = true)
     {
         $io = $this->getIO();
diff --git a/src/Composer/Command/RunScriptCommand.php b/src/Composer/Command/RunScriptCommand.php
index 052139f8b..6bb0f0a64 100644
--- a/src/Composer/Command/RunScriptCommand.php
+++ b/src/Composer/Command/RunScriptCommand.php
@@ -44,6 +44,9 @@ class RunScriptCommand extends BaseCommand
         ScriptEvents::POST_AUTOLOAD_DUMP,
     );
 
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
diff --git a/src/Composer/Command/ScriptAliasCommand.php b/src/Composer/Command/ScriptAliasCommand.php
index 63f0f9e6a..1cf3e2ba9 100644
--- a/src/Composer/Command/ScriptAliasCommand.php
+++ b/src/Composer/Command/ScriptAliasCommand.php
@@ -27,6 +27,10 @@ class ScriptAliasCommand extends BaseCommand
     /** @var string */
     private $description;
 
+    /**
+     * @param string $script
+     * @param string $description
+     */
     public function __construct($script, $description)
     {
         $this->script = $script;
@@ -35,6 +39,9 @@ class ScriptAliasCommand extends BaseCommand
         parent::__construct();
     }
 
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -57,6 +64,9 @@ EOT
         ;
     }
 
+    /**
+     * @return int
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $composer = $this->getComposer();
diff --git a/src/Composer/Command/SearchCommand.php b/src/Composer/Command/SearchCommand.php
index 8b51d530a..a4e63198b 100644
--- a/src/Composer/Command/SearchCommand.php
+++ b/src/Composer/Command/SearchCommand.php
@@ -29,6 +29,9 @@ use Composer\Plugin\PluginEvents;
  */
 class SearchCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
diff --git a/src/Composer/Command/SelfUpdateCommand.php b/src/Composer/Command/SelfUpdateCommand.php
index bfa1bd481..b21f7bf83 100644
--- a/src/Composer/Command/SelfUpdateCommand.php
+++ b/src/Composer/Command/SelfUpdateCommand.php
@@ -38,6 +38,9 @@ class SelfUpdateCommand extends BaseCommand
     const HOMEPAGE = 'getcomposer.org';
     const OLD_INSTALL_EXT = '-old.phar';
 
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -70,6 +73,10 @@ EOT
         ;
     }
 
+    /**
+     * @return int
+     * @throws FilesystemException
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $config = Factory::createConfig();
@@ -105,7 +112,8 @@ EOT
         $localFilename = realpath($_SERVER['argv'][0]) ?: $_SERVER['argv'][0];
 
         if ($input->getOption('update-keys')) {
-            return $this->fetchKeys($io, $config);
+            $this->fetchKeys($io, $config);
+            return 0;
         }
 
         // ensure composer.phar location is accessible
@@ -324,6 +332,10 @@ TAGSPUBKEY
         return 0;
     }
 
+    /**
+     * @return void
+     * @throws \Exception
+     */
     protected function fetchKeys(IOInterface $io, Config $config)
     {
         if (!$io->isInteractive()) {
@@ -370,7 +382,10 @@ TAGSPUBKEY
     }
 
     /**
+     * @param string $rollbackDir
+     * @param string $localFilename
      * @return int
+     * @throws FilesystemException
      */
     protected function rollback(OutputInterface $output, $rollbackDir, $localFilename)
     {
@@ -451,6 +466,12 @@ TAGSPUBKEY
         }
     }
 
+    /**
+     * @param string $rollbackDir
+     * @param string|null $except
+     *
+     * @return void
+     */
     protected function cleanBackups($rollbackDir, $except = null)
     {
         $finder = $this->getOldInstallationFinder($rollbackDir);
@@ -468,6 +489,7 @@ TAGSPUBKEY
     }
 
     /**
+     * @param string $rollbackDir
      * @return string|false
      */
     protected function getLastBackupVersion($rollbackDir)
@@ -484,6 +506,7 @@ TAGSPUBKEY
     }
 
     /**
+     * @param string $rollbackDir
      * @return Finder
      */
     protected function getOldInstallationFinder($rollbackDir)
diff --git a/src/Composer/Command/ShowCommand.php b/src/Composer/Command/ShowCommand.php
index 1640d0562..ac75b202d 100644
--- a/src/Composer/Command/ShowCommand.php
+++ b/src/Composer/Command/ShowCommand.php
@@ -59,6 +59,9 @@ class ShowCommand extends BaseCommand
     /** @var ?RepositorySet */
     private $repositorySet;
 
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -553,6 +556,9 @@ EOT
         return $exitCode;
     }
 
+    /**
+     * @return string[]
+     */
     protected function getRootRequires()
     {
         $rootPackage = $this->getComposer()->getPackage();
@@ -563,6 +569,9 @@ EOT
         );
     }
 
+    /**
+     * @return array|string|string[]
+     */
     protected function getVersionStyle(PackageInterface $latestPackage, PackageInterface $package)
     {
         return $this->updateStatusToVersionStyle($this->getUpdateStatus($latestPackage, $package));
@@ -571,12 +580,10 @@ EOT
     /**
      * finds a package by name and version if provided
      *
-     * @param  InstalledRepository        $installedRepo
-     * @param  RepositoryInterface        $repos
      * @param  string                     $name
      * @param  ConstraintInterface|string $version
      * @throws \InvalidArgumentException
-     * @return array                      array(CompletePackageInterface, array of versions)
+     * @return array{CompletePackageInterface|null, array<string, string>}
      */
     protected function getPackage(InstalledRepository $installedRepo, RepositoryInterface $repos, $name, $version = null)
     {
@@ -617,10 +624,10 @@ EOT
     /**
      * Prints package info.
      *
-     * @param CompletePackageInterface $package
-     * @param array                    $versions
-     * @param InstalledRepository      $installedRepo
+     * @param array<string, string>    $versions
      * @param PackageInterface|null    $latestPackage
+     *
+     * @return void
      */
     protected function printPackageInfo(CompletePackageInterface $package, array $versions, InstalledRepository $installedRepo, PackageInterface $latestPackage = null)
     {
@@ -645,10 +652,10 @@ EOT
     /**
      * Prints package metadata.
      *
-     * @param CompletePackageInterface $package
-     * @param array                    $versions
-     * @param InstalledRepository      $installedRepo
+     * @param array<string, string>    $versions
      * @param PackageInterface|null    $latestPackage
+     *
+     * @return void
      */
     protected function printMeta(CompletePackageInterface $package, array $versions, InstalledRepository $installedRepo, PackageInterface $latestPackage = null)
     {
@@ -713,9 +720,9 @@ EOT
     /**
      * Prints all available versions of this package and highlights the installed one if any.
      *
-     * @param CompletePackageInterface $package
-     * @param array                    $versions
-     * @param InstalledRepository      $installedRepo
+     * @param array<string, string> $versions
+     *
+     * @return void
      */
     protected function printVersions(CompletePackageInterface $package, array $versions, InstalledRepository $installedRepo)
     {
@@ -741,9 +748,10 @@ EOT
     /**
      * print link objects
      *
-     * @param CompletePackageInterface $package
      * @param string                   $linkType
      * @param string                   $title
+     *
+     * @return void
      */
     protected function printLinks(CompletePackageInterface $package, $linkType, $title = null)
     {
@@ -761,7 +769,7 @@ EOT
     /**
      * Prints the licenses of a package with metadata
      *
-     * @param CompletePackageInterface $package
+     * @return void
      */
     protected function printLicenses(CompletePackageInterface $package)
     {
@@ -791,10 +799,9 @@ EOT
     /**
      * Prints package info in JSON format.
      *
-     * @param CompletePackageInterface $package
-     * @param array                    $versions
-     * @param InstalledRepository      $installedRepo
-     * @param PackageInterface|null    $latestPackage
+     * @param array<string, string>    $versions
+     *
+     * @return void
      */
     protected function printPackageInfoAsJson(CompletePackageInterface $package, array $versions, InstalledRepository $installedRepo, PackageInterface $latestPackage = null)
     {
@@ -862,6 +869,11 @@ EOT
         $this->getIO()->write(JsonFile::encode($json));
     }
 
+    /**
+     * @param array<string, string|string[]|null> $json
+     * @param array<string, string> $versions
+     * @return array<string, string|string[]|null>
+     */
     private function appendVersions($json, array $versions)
     {
         uasort($versions, 'version_compare');
@@ -871,6 +883,10 @@ EOT
         return $json;
     }
 
+    /**
+     * @param array<string, string|string[]|null> $json
+     * @return array<string, string|string[]|null>
+     */
     private function appendLicenses($json, CompletePackageInterface $package)
     {
         if ($licenses = $package->getLicense()) {
@@ -894,6 +910,10 @@ EOT
         return $json;
     }
 
+    /**
+     * @param array<string, string|string[]|null> $json
+     * @return array<string, string|string[]|null>
+     */
     private function appendAutoload($json, CompletePackageInterface $package)
     {
         if ($package->getAutoload()) {
@@ -923,6 +943,10 @@ EOT
         return $json;
     }
 
+    /**
+     * @param array<string, string|string[]|null> $json
+     * @return array<string, string|string[]|null>
+     */
     private function appendLinks($json, CompletePackageInterface $package)
     {
         foreach (Link::$TYPES as $linkType) {
@@ -932,6 +956,11 @@ EOT
         return $json;
     }
 
+    /**
+     * @param array<string, string|string[]|null> $json
+     * @param string $linkType
+     * @return array<string, string|string[]|null>
+     */
     private function appendLink($json, CompletePackageInterface $package, $linkType)
     {
         $links = $package->{'get' . ucfirst($linkType)}();
@@ -950,7 +979,7 @@ EOT
     /**
      * Init styles for tree
      *
-     * @param OutputInterface $output
+     * @return void
      */
     protected function initStyles(OutputInterface $output)
     {
@@ -971,7 +1000,8 @@ EOT
     /**
      * Display the tree
      *
-     * @param array $arrayTree
+     * @param array<int, array<string, string|array>> $arrayTree
+     * @return void
      */
     protected function displayPackageTree(array $arrayTree)
     {
@@ -1016,10 +1046,7 @@ EOT
     /**
      * Generate the package tree
      *
-     * @param  PackageInterface    $package
-     * @param  InstalledRepository $installedRepo
-     * @param  RepositoryInterface $remoteRepos
-     * @return array
+     * @return array<string, array<int, array<string, array|string>>|string|null>
      */
     protected function generatePackageTree(
         PackageInterface $package,
@@ -1061,10 +1088,12 @@ EOT
     /**
      * Display a package tree
      *
-     * @param array|string $package
-     * @param array        $packagesInTree
-     * @param string       $previousTreeBar
-     * @param int          $level
+     * @param array<string, array<int, array<string, array|string>>|string|null>|string $package
+     * @param array<int, string|array> $packagesInTree
+     * @param string $previousTreeBar
+     * @param int $level
+     *
+     * @return void
      */
     protected function displayTree(
         $package,
@@ -1114,12 +1143,9 @@ EOT
     /**
      * Display a package tree
      *
-     * @param  string              $name
-     * @param  Link                $link
-     * @param  InstalledRepository $installedRepo
-     * @param  RepositoryInterface $remoteRepos
-     * @param  array               $packagesInTree
-     * @return array
+     * @param  string   $name
+     * @param  string[] $packagesInTree
+     * @return array<int, array<string, array<int, array<string, string>>|string>>
      */
     protected function addTree(
         $name,
@@ -1161,6 +1187,10 @@ EOT
         return $children;
     }
 
+    /**
+     * @param string $updateStatus
+     * @return string
+     */
     private function updateStatusToVersionStyle($updateStatus)
     {
         // 'up-to-date' is printed green
@@ -1169,6 +1199,9 @@ EOT
         return str_replace(array('up-to-date', 'semver-safe-update', 'update-possible'), array('info', 'highlight', 'comment'), $updateStatus);
     }
 
+    /**
+     * @return string
+     */
     private function getUpdateStatus(PackageInterface $latestPackage, PackageInterface $package)
     {
         if ($latestPackage->getFullPrettyVersion() === $package->getFullPrettyVersion()) {
@@ -1188,6 +1221,11 @@ EOT
         return 'update-possible';
     }
 
+    /**
+     * @param string $line
+     *
+     * @return void
+     */
     private function writeTreeLine($line)
     {
         $io = $this->getIO();
@@ -1201,10 +1239,7 @@ EOT
     /**
      * Given a package, this finds the latest package matching it
      *
-     * @param PackageInterface   $package
-     * @param Composer           $composer
-     * @param PlatformRepository $platformRepo
-     * @param bool               $minorOnly
+     * @param bool $minorOnly
      *
      * @return PackageInterface|false
      */
@@ -1257,10 +1292,8 @@ EOT
     /**
      * Find package requires and child requires
      *
-     * @param  RepositoryInterface $repo
-     * @param  PackageInterface    $package
-     * @param  array               $bucket
-     * @return array
+     * @param  array<PackageInterface> $bucket
+     * @return array<PackageInterface>
      */
     private function filterRequiredPackages(RepositoryInterface $repo, PackageInterface $package, $bucket = array())
     {
diff --git a/src/Composer/Command/StatusCommand.php b/src/Composer/Command/StatusCommand.php
index ede91ac13..cc4876fd0 100644
--- a/src/Composer/Command/StatusCommand.php
+++ b/src/Composer/Command/StatusCommand.php
@@ -37,6 +37,7 @@ class StatusCommand extends BaseCommand
     const EXIT_CODE_VERSION_CHANGES = 4;
 
     /**
+     * @return void
      * @throws \Symfony\Component\Console\Exception\InvalidArgumentException
      */
     protected function configure()
@@ -59,8 +60,6 @@ EOT
     }
 
     /**
-     * @param  InputInterface  $input
-     * @param  OutputInterface $output
      * @return int
      */
     protected function execute(InputInterface $input, OutputInterface $output)
@@ -82,7 +81,6 @@ EOT
     }
 
     /**
-     * @param  InputInterface $input
      * @return int
      */
     private function doExecute(InputInterface $input)
diff --git a/src/Composer/Command/SuggestsCommand.php b/src/Composer/Command/SuggestsCommand.php
index cb1f4e9a6..c6da9fc5d 100644
--- a/src/Composer/Command/SuggestsCommand.php
+++ b/src/Composer/Command/SuggestsCommand.php
@@ -23,6 +23,9 @@ use Symfony\Component\Console\Output\OutputInterface;
 
 class SuggestsCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
diff --git a/src/Composer/Command/UpdateCommand.php b/src/Composer/Command/UpdateCommand.php
index 7c2a7dcee..84c99ffd7 100644
--- a/src/Composer/Command/UpdateCommand.php
+++ b/src/Composer/Command/UpdateCommand.php
@@ -36,6 +36,9 @@ use Symfony\Component\Console\Question\Question;
  */
 class UpdateCommand extends BaseCommand
 {
+    /**
+     * @return void
+     */
     protected function configure()
     {
         $this
@@ -105,6 +108,10 @@ EOT
         ;
     }
 
+    /**
+     * @return int
+     * @throws \Exception
+     */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $io = $this->getIO();
@@ -241,6 +248,10 @@ EOT
         return $install->run();
     }
 
+    /**
+     * @param array<string> $packages
+     * @return array<string>
+     */
     private function getPackagesInteractively(IOInterface $io, InputInterface $input, OutputInterface $output, Composer $composer, array $packages)
     {
         if (!$input->isInteractive()) {
@@ -305,6 +316,7 @@ EOT
     }
 
     /**
+     * @param string $constraint
      * @return Link
      */
     private function appendConstraintToLink(Link $link, $constraint)
diff --git a/src/Composer/Command/ValidateCommand.php b/src/Composer/Command/ValidateCommand.php
index fdb424423..e66cbf23b 100644
--- a/src/Composer/Command/ValidateCommand.php
+++ b/src/Composer/Command/ValidateCommand.php
@@ -13,6 +13,7 @@
 namespace Composer\Command;
 
 use Composer\Factory;
+use Composer\IO\IOInterface;
 use Composer\Package\Loader\ValidatingArrayLoader;
 use Composer\Plugin\CommandEvent;
 use Composer\Plugin\PluginEvents;
@@ -35,6 +36,7 @@ class ValidateCommand extends BaseCommand
 {
     /**
      * configure
+     * @return void
      */
     protected function configure()
     {
@@ -65,9 +67,6 @@ EOT
     }
 
     /**
-     * @param InputInterface  $input
-     * @param OutputInterface $output
-     *
      * @return int
      */
     protected function execute(InputInterface $input, OutputInterface $output)
@@ -161,7 +160,19 @@ EOT
         return max($eventCode, $exitCode);
     }
 
-    private function outputResult($io, $name, &$errors, &$warnings, $checkPublish = false, $publishErrors = array(), $checkLock = false, $lockErrors = array(), $printSchemaUrl = false)
+    /**
+     * @param string $name
+     * @param string[] $errors
+     * @param string[] $warnings
+     * @param bool $checkPublish
+     * @param string[] $publishErrors
+     * @param bool $checkLock
+     * @param string[] $lockErrors
+     * @param bool $printSchemaUrl
+     *
+     * @return void
+     */
+    private function outputResult(IOInterface $io, $name, &$errors, &$warnings, $checkPublish = false, $publishErrors = array(), $checkLock = false, $lockErrors = array(), $printSchemaUrl = false)
     {
         $doPrintSchemaUrl = false;