[DependencyInjection] Fail when dumping a Definition with no class nor factory

Author: nicolas-grekas

Dumper/PhpDumper.php

@@ -1210,11 +1210,6 @@ private function dumpValue($value, $interpolate = true)
             foreach ($value->getArguments() as $argument) {
                 $arguments[] = $this->dumpValue($argument);
             }
-            $class = $this->dumpValue($value->getClass());
-
-            if (false !== strpos($class, '$')) {
-                throw new RuntimeException('Cannot dump definitions which have a variable class name.');
-            }
 
             if (null !== $value->getFactoryMethod()) {
                 if (null !== $value->getFactoryClass()) {
@@ -1228,6 +1223,15 @@ private function dumpValue($value, $interpolate = true)
                 }
             }
 
+            $class = $value->getClass();
+            if (null === $class) {
+                throw new RuntimeException('Cannot dump definitions which have no class nor factory.');
+            }
+            $class = $this->dumpValue($class);
+            if (false !== strpos($class, '$')) {
+                throw new RuntimeException('Cannot dump definitions which have a variable class name.');
+            }
+
             return sprintf('new \\%s(%s)', substr(str_replace('\\\\', '\\', $class), 1, -1), implode(', ', $arguments));
         } elseif ($value instanceof Variable) {
             return '$'.$value;