diff --git a/src/Cache/FileSystemCache.php b/src/Cache/FileSystemCache.php
index 8a507f7..5e9f523 100644
--- a/src/Cache/FileSystemCache.php
+++ b/src/Cache/FileSystemCache.php
@@ -18,7 +18,7 @@ class FileSystemCache implements Cache
 
     public function __construct()
     {
-        if (PHP_OS === 'WINNT') {
+        if (strtoupper(substr(php_uname('s'), 0, 3)) === 'WIN') {
             $this->cacheDir = getenv('LOCALAPPDATA') . '\\PHP Language Server\\';
         } else if (getenv('XDG_CACHE_HOME')) {
             $this->cacheDir = getenv('XDG_CACHE_HOME') . '/phpls/';
diff --git a/src/Server/TextDocument.php b/src/Server/TextDocument.php
index b087807..a23358f 100644
--- a/src/Server/TextDocument.php
+++ b/src/Server/TextDocument.php
@@ -412,7 +412,7 @@ class TextDocument
             if (preg_match('/\/vendor\/([^\/]+\/[^\/]+)\//', $def->symbolInformation->location->uri, $matches) && $this->composerLock !== null) {
                 // Definition is inside a dependency
                 $packageName = $matches[1];
-                foreach ($this->composerLock->packages as $package) {
+                foreach (array_merge($this->composerLock->packages, $this->composerLock->{'packages-dev'}) as $package) {
                     if ($package->name === $packageName) {
                         $symbol->package = $package;
                         break;
diff --git a/src/Server/Workspace.php b/src/Server/Workspace.php
index 55821ac..2699de4 100644
--- a/src/Server/Workspace.php
+++ b/src/Server/Workspace.php
@@ -125,7 +125,7 @@ class Workspace
                     }
                     // Find out package name
                     $packageName = getPackageName($this->composerJson, $def->symbolInformation->location->uri);
-                    foreach ($this->composerLock->packages as $package) {
+                    foreach (array_merge($this->composerLock->packages, $this->composerLock->{'packages-dev'}) as $package) {
                         if ($package->name === $packageName) {
                             $symbol->package = $package;
                             break;
@@ -166,7 +166,7 @@ class Workspace
             return [];
         }
         $dependencyReferences = [];
-        foreach ($this->composerLock->packages as $package) {
+        foreach (array_merge($this->composerLock->packages, $this->composerLock->{'packages-dev'}) as $package) {
             $dependencyReferences[] = new DependencyReference($package);
         }
         return $dependencyReferences;