[PHP 5.5] Make StringClassNameToClassConstantRector skip lcfirst (#2888)

composer.json

@@ -103,6 +103,7 @@
             "rules-tests/Renaming/Rector/FileWithoutNamespace/PseudoNamespaceToNamespaceRector/Source"
         ],
         "files": [
+            "stubs/Directory.php",
             "stubs/Doctrine/Persistence/ObjectManager.php",
             "stubs/Doctrine/Common/Persistence/ObjectManager.php",
             "rules-tests/Transform/Rector/FuncCall/FuncCallToMethodCallRector/Source/some_view_function.php",

rules-tests/Php55/Rector/String_/StringClassNameToClassConstantRector/Fixture/keep_short_class_names.php.inc

@@ -0,0 +1,11 @@
+<?php
+
+namespace Rector\Tests\Php55\Rector\String_\StringClassNameToClassConstantRector\Fixture;
+
+final class KeepShortClassNames
+{
+    public function run()
+    {
+        return 'directory';
+    }
+}

rules/Php55/Rector/String_/StringClassNameToClassConstantRector.php

@@ -144,6 +144,11 @@ private function shouldSkip(string $classLikeName, String_ $string): bool
             return true;
         }
 
+        // possibly string
+        if (ctype_lower($classLikeName[0])) {
+            return true;
+        }
+
         foreach ($this->classesToSkip as $classToSkip) {
             if ($this->nodeNameResolver->isStringName($classLikeName, $classToSkip)) {
                 return true;

stubs/Directory.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+if (class_exists('Directory')) {
+    return;
+}
+
+final class Directory
+{
+
+}