diff --git a/src/main/java/com/mysema/query/ExtQuery.java b/src/main/java/com/mysema/query/ExtQuery.java
index a00facad1..0c18674a3 100644
--- a/src/main/java/com/mysema/query/ExtQuery.java
+++ b/src/main/java/com/mysema/query/ExtQuery.java
@@ -8,7 +8,7 @@ package com.mysema.query;
 import com.mysema.query.grammar.Types.*;
 
 /**
- * ExtQuery provides
+ * ExtQuery externds the Query interface to provide innerJoin, leftJoin and with methods
  *
  * @author tiwe
  * @version $Id$
diff --git a/src/main/java/com/mysema/query/grammar/Grammar.java b/src/main/java/com/mysema/query/grammar/Grammar.java
index 8b93c9bee..18ae6a956 100644
--- a/src/main/java/com/mysema/query/grammar/Grammar.java
+++ b/src/main/java/com/mysema/query/grammar/Grammar.java
@@ -32,7 +32,9 @@ public class Grammar {
         return op;
     }
     
+    @SuppressWarnings("unchecked")
     static <A> Expr<A> _const(A obj){
+        if (obj instanceof Expr) return (Expr<A>)obj;
         ConstantExpr<A> e = new ConstantExpr<A>();
         e.constant = obj;
         return e;