Throw exception when PHP start tag is missing

src/Symfony/Component/Routing/Loader/AnnotationFileLoader.php

@@ -92,6 +92,11 @@ class AnnotationFileLoader extends FileLoader
         $class = false;
         $namespace = false;
         $tokens = token_get_all(file_get_contents($file));
+
+        if (1 === count($tokens) && T_INLINE_HTML === $tokens[0][0]) {
+            throw new \InvalidArgumentException(sprintf('The file "%s" does not contain PHP code. Did you forgot to add the "<?php" start tag at the beginning of the file?', $file));
+        }
+
         for ($i = 0; isset($tokens[$i]); ++$i) {
             $token = $tokens[$i];
 

src/Symfony/Component/Routing/Tests/Fixtures/OtherAnnotatedClasses/NoStartTagClass.php

@@ -0,0 +1,3 @@
+class NoStartTagClass
+{
+}

src/Symfony/Component/Routing/Tests/Loader/AnnotationFileLoaderTest.php

@@ -45,6 +45,15 @@ class AnnotationFileLoaderTest extends AbstractAnnotationLoaderTest
         $this->loader->load(__DIR__.'/../Fixtures/AnnotatedClasses/FooTrait.php');
     }
 
+    /**
+     * @expectedException \InvalidArgumentException
+     * @expectedExceptionMessage Did you forgot to add the "<?php" start tag at the beginning of the file?
+     */
+    public function testLoadFileWithoutStartTag()
+    {
+        $this->loader->load(__DIR__.'/../Fixtures/OtherAnnotatedClasses/NoStartTagClass.php');
+    }
+
     /**
      * @requires PHP 5.6
      */