diff --git a/src/Reflection/BetterReflection/SourceLocator/ComposerJsonAndInstalledJsonSourceLocatorMaker.php b/src/Reflection/BetterReflection/SourceLocator/ComposerJsonAndInstalledJsonSourceLocatorMaker.php
index 1195311fd2..83e7d86992 100644
--- a/src/Reflection/BetterReflection/SourceLocator/ComposerJsonAndInstalledJsonSourceLocatorMaker.php
+++ b/src/Reflection/BetterReflection/SourceLocator/ComposerJsonAndInstalledJsonSourceLocatorMaker.php
@@ -129,7 +129,7 @@ public function create(string $projectInstallationPath): ?SourceLocator
 		}
 
 		if (count($files) > 0) {
-			$locators[] = $this->optimizedDirectorySourceLocatorFactory->createByFiles($files);
+			$locators[] = $this->optimizedDirectorySourceLocatorFactory->createByFiles($files, 'odsl-installed-files');
 		}
 
 		$binDir = ComposerHelper::getBinDirFromComposerConfig($projectInstallationPath, $composer);
diff --git a/src/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorFactory.php b/src/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorFactory.php
index 5803517e63..c64ff2dd2b 100644
--- a/src/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorFactory.php
+++ b/src/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorFactory.php
@@ -52,6 +52,15 @@ public function createByDirectory(string $directory): OptimizedDirectorySourceLo
 		}
 
 		$cacheKey = sprintf('odsl-%s', $directory);
+		return $this->createCachedDirectorySourceLocator($fileHashes, $cacheKey);
+	}
+
+	/**
+	 * @param array<string, string> $fileHashes
+	 * @param non-empty-string $cacheKey
+	 */
+	private function createCachedDirectorySourceLocator(array $fileHashes, string $cacheKey): OptimizedDirectorySourceLocator
+	{
 		$variableCacheKey = 'v1';
 
 		/** @var array<string, array{string, string[], string[], string[]}>|null $cached */
@@ -93,23 +102,20 @@ public function createByDirectory(string $directory): OptimizedDirectorySourceLo
 
 	/**
 	 * @param string[] $files
+	 * @param non-empty-string&literal-string $uniqueCacheIdentifier
 	 */
-	public function createByFiles(array $files): OptimizedDirectorySourceLocator
+	public function createByFiles(array $files, string $uniqueCacheIdentifier): OptimizedDirectorySourceLocator
 	{
-		$symbols = [];
+		$fileHashes = [];
 		foreach ($files as $file) {
-			[$newClasses, $newFunctions, $newConstants] = $this->findSymbols($file);
-			$symbols[$file] = ['', $newClasses, $newFunctions, $newConstants];
+			$hash = sha1_file($file);
+			if ($hash === false) {
+				continue;
+			}
+			$fileHashes[$file] = $hash;
 		}
 
-		[$classToFile, $functionToFiles, $constantToFile] = $this->changeStructure($symbols);
-
-		return new OptimizedDirectorySourceLocator(
-			$this->fileNodesFetcher,
-			$classToFile,
-			$functionToFiles,
-			$constantToFile,
-		);
+		return $this->createCachedDirectorySourceLocator($fileHashes, $uniqueCacheIdentifier);
 	}
 
 	/**
diff --git a/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.php b/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.php
index 06c9407908..30b555e7b3 100644
--- a/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.php
+++ b/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.php
@@ -307,7 +307,7 @@ public function testFunctionDoesNotExist(string $functionName): void
 	public function testBug5525(): void
 	{
 		$factory = self::getContainer()->getByType(OptimizedDirectorySourceLocatorFactory::class);
-		$locator = $factory->createByFiles([__DIR__ . '/data/bug-5525.php']);
+		$locator = $factory->createByFiles([__DIR__ . '/data/bug-5525.php'], 'bug5525-odsl-installed-files');
 		$reflector = new DefaultReflector($locator);
 
 		$class = $reflector->reflectClass('Faker\\Provider\\nl_BE\\Text');