DDC-127 - Special Case with invalid input parameter in DQL leads to php notice instead of an exception.

lib/Doctrine/ORM/Query/AST/InputParameter.php

@@ -37,10 +37,16 @@ class InputParameter extends Node
     public $isNamed;
     public $name;
 
+    /**
+     * @param string $value
+     */
     public function __construct($value)
     {
         if (strlen($value) == 1) {
-            throw new \InvalidArgumentException("Invalid parameter format.");
+            throw new \InvalidArgumentException(
+                "Invalid parameter format, '".$value."' given, ".
+                "but :<name> or ?<num> expected."
+            );
         }
 
         $param = substr($value, 1);