Implement existing fix from https://github.com/felixfbecker/php-language-server/issues/462#issuecomment-546696984.

src/FilesFinder/FileSystemFilesFinder.php

@@ -3,7 +3,6 @@ declare(strict_types = 1);
 
 namespace LanguageServer\FilesFinder;
 
-use Webmozart\Glob\Iterator\GlobIterator;
 use Sabre\Event\Promise;
 use function Sabre\Event\coroutine;
 use function LanguageServer\{pathToUri, timeout};
@@ -23,7 +22,7 @@ class FileSystemFilesFinder implements FilesFinder
             $uris = [];
             foreach (new GlobIterator($glob) as $path) {
                 // Exclude any directories that also match the glob pattern
-                if (!is_dir($path)) {
+                if (!is_dir($path) || !is_readable($path)) {
                     $uris[] = pathToUri($path);
                 }
 

src/FilesFinder/GlobIterator.php

@@ -0,0 +1,84 @@
+<?php
+declare (strict_types = 1);
+
+namespace LanguageServer\FilesFinder;
+
+use ArrayIterator;
+use EmptyIterator;
+use IteratorIterator;
+use RecursiveIteratorIterator;
+use Webmozart\Glob\Glob;
+use Webmozart\Glob\Iterator\GlobFilterIterator;
+use Webmozart\Glob\Iterator\RecursiveDirectoryIterator;
+
+/**
+ * Returns filesystem paths matching a glob.
+ *
+ * @since  1.0
+ *
+ * @author Bernhard Schussek <bschussek@gmail.com>
+ *
+ * @see    Glob
+ */
+class GlobIterator extends IteratorIterator
+{
+    /**
+     * Creates a new iterator.
+     *
+     * @param string $glob  The glob pattern.
+     * @param int    $flags A bitwise combination of the flag constants in
+     *                      {@link Glob}.
+     */
+    public function __construct($glob, $flags = 0)
+    {
+        $basePath = Glob::getBasePath($glob, $flags);
+        if (!Glob::isDynamic($glob) && file_exists($glob)) {
+            // If the glob is a file path, return that path
+            $innerIterator = new ArrayIterator(array($glob));
+        } elseif (is_dir($basePath)) {
+            // Use the system's much more efficient glob() function where we can
+            if (
+                // glob() does not support /**/
+                false === strpos($glob, '/**/') &&
+                // glob() does not support stream wrappers
+                false === strpos($glob, '://') &&
+                // glob() does not support [^...] on Windows
+                ('\\' !== DIRECTORY_SEPARATOR || false === strpos($glob, '[^'))
+            ) {
+                $results = glob($glob, GLOB_BRACE);
+
+                // $results may be empty or false if $glob is invalid
+                if (empty($results)) {
+                    // Parse glob and provoke errors if invalid
+                    Glob::toRegEx($glob);
+
+                    // Otherwise return empty result set
+                    $innerIterator = new EmptyIterator();
+                } else {
+                    $innerIterator = new ArrayIterator($results);
+                }
+            } else {
+                // Otherwise scan the glob's base directory for matches
+                $innerIterator = new GlobFilterIterator(
+                    $glob,
+                    new RecursiveIteratorIterator(
+                        new RecursiveDirectoryIterator(
+                            $basePath,
+                            RecursiveDirectoryIterator::CURRENT_AS_PATHNAME,
+                            RecursiveDirectoryIterator::SKIP_DOTS
+                        ),
+                        RecursiveIteratorIterator::SELF_FIRST,
+                        RecursiveIteratorIterator::CATCH_GET_CHILD
+                    ),
+                    GlobFilterIterator::FILTER_VALUE,
+                    $flags
+                );
+            }
+        } else {
+            // If the glob's base directory does not exist, return nothing
+            $innerIterator = new EmptyIterator();
+        }
+
+        parent::__construct($innerIterator);
+    }
+}