diff --git a/typo3/sysext/core/Classes/Core/ClassLoadingInformationGenerator.php b/typo3/sysext/core/Classes/Core/ClassLoadingInformationGenerator.php
index 05e5116b743e044670ddbb37897d3074ff27a3f2..7c4a9a7f09fc72b2f859113b6903f5f700669f87 100644
--- a/typo3/sysext/core/Classes/Core/ClassLoadingInformationGenerator.php
+++ b/typo3/sysext/core/Classes/Core/ClassLoadingInformationGenerator.php
@@ -235,7 +235,11 @@ EOF;
 		$packageRealPath = GeneralUtility::fixWindowsFilePath(realpath($packagePath));
 		$relativePackagePath = rtrim(substr($packagePath, strlen($this->installationRoot)), '/');
 		if ($relativeToRoot) {
-			$relativePathToClassFile = $relativePackagePath . '/' . ltrim(substr($realPathOfClassFile, strlen($packageRealPath)), '/');
+			if ($realPathOfClassFile === $packageRealPath) {
+				$relativePathToClassFile = $relativePackagePath;
+			} else {
+				$relativePathToClassFile = $relativePackagePath . '/' . ltrim(substr($realPathOfClassFile, strlen($packageRealPath)), '/');
+			}
 		} else {
 			$relativePathToClassFile = ltrim(substr($realPathOfClassFile, strlen($packageRealPath)), '/');
 		}
diff --git a/typo3/sysext/core/Tests/Unit/Core/ClassLoadingInformationGeneratorTest.php b/typo3/sysext/core/Tests/Unit/Core/ClassLoadingInformationGeneratorTest.php
index 7015471c4eee41004fc2553da7d50de2aa57ee55..591f6220e0bd1758760d7e4d70866e5533cab7ba 100644
--- a/typo3/sysext/core/Tests/Unit/Core/ClassLoadingInformationGeneratorTest.php
+++ b/typo3/sysext/core/Tests/Unit/Core/ClassLoadingInformationGeneratorTest.php
@@ -71,7 +71,7 @@ class ClassLoadingInformationGeneratorTest extends UnitTestCase {
 
 		$this->assertArrayHasKey('psr-4File', $files);
 		$this->assertArrayHasKey('classMapFile', $files);
-		$this->assertContains('\'TYPO3\\\\CMS\\\\TestExtension\\\\\' => array($typo3InstallDir . \'/Fixtures/test_extension/Classes/\')', $files['psr-4File']);
+		$this->assertContains('\'TYPO3\\\\CMS\\\\TestExtension\\\\\' => array($typo3InstallDir . \'/Fixtures/test_extension/Classes\')', $files['psr-4File']);
 		$this->assertContains('$typo3InstallDir . \'/Fixtures/test_extension/Resources/PHP/Test.php\'', $files['classMapFile']);
 	}
 
diff --git a/typo3/sysext/core/Tests/Unit/Core/Fixtures/test_extension/composer.json b/typo3/sysext/core/Tests/Unit/Core/Fixtures/test_extension/composer.json
index fb6d1c88d458c32cc4ade03d2358ac7dc488c2db..215103bef4748532ad54de10e7599415efa46aa8 100644
--- a/typo3/sysext/core/Tests/Unit/Core/Fixtures/test_extension/composer.json
+++ b/typo3/sysext/core/Tests/Unit/Core/Fixtures/test_extension/composer.json
@@ -15,6 +15,6 @@
 		"psr-4": {
 			"TYPO3\\CMS\\TestExtension\\": "Classes/"
 		},
-		"classmap": ["Resources/PHP/"]
+		"classmap": ["Resources/PHP/Test.php"]
 	}
 }