diff --git a/querydsl-core/src/main/java/com/mysema/query/grammar/Grammar.java b/querydsl-core/src/main/java/com/mysema/query/grammar/Grammar.java
index bb4a757fe..300a6feb4 100644
--- a/querydsl-core/src/main/java/com/mysema/query/grammar/Grammar.java
+++ b/querydsl-core/src/main/java/com/mysema/query/grammar/Grammar.java
@@ -10,8 +10,8 @@ import static com.mysema.query.grammar.types.Factory.createBoolean;
 import static com.mysema.query.grammar.types.Factory.createConstant;
 import static com.mysema.query.grammar.types.Factory.createNumber;
 
+import com.mysema.query.grammar.types.CollectionType;
 import com.mysema.query.grammar.types.Expr;
-import com.mysema.query.grammar.types.Expr.CollectionType;
 
 /**
  * Grammar provides the factory methods for the fluent grammar
diff --git a/querydsl-core/src/main/java/com/mysema/query/grammar/types/Alias.java b/querydsl-core/src/main/java/com/mysema/query/grammar/types/Alias.java
index aed47a87d..3780e71be 100644
--- a/querydsl-core/src/main/java/com/mysema/query/grammar/types/Alias.java
+++ b/querydsl-core/src/main/java/com/mysema/query/grammar/types/Alias.java
@@ -11,7 +11,9 @@ package com.mysema.query.grammar.types;
  * @author tiwe
  * @version $Id$
  */
-public class Alias {
+public interface Alias {
+    
+    Expr<?> getFrom();
     
     public static class Entity<D> extends Expr.Entity<D> implements ToPath{
         private final Expr<?> from;
@@ -37,7 +39,7 @@ public class Alias {
         public  Path<?> getTo() {return to;}        
     }
             
-    public static class Simple<D> extends Expr.Simple<D>{     
+    public static class Simple<D> extends Expr.Simple<D> implements Alias{     
         private final Expr<?> from;
         private final java.lang.String to;
         public Simple(Expr<D> from, java.lang.String to) {
@@ -52,8 +54,7 @@ public class Alias {
         public java.lang.String getTo() {return to;}  
     }
     
-    public interface ToPath{
-        Expr<?> getFrom();
+    public interface ToPath extends Alias{        
         Path<?> getTo();
     }
 
diff --git a/querydsl-core/src/main/java/com/mysema/query/grammar/types/CollectionType.java b/querydsl-core/src/main/java/com/mysema/query/grammar/types/CollectionType.java
new file mode 100644
index 000000000..3547db116
--- /dev/null
+++ b/querydsl-core/src/main/java/com/mysema/query/grammar/types/CollectionType.java
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2008 Mysema Ltd.
+ * All rights reserved.
+ * 
+ */
+package com.mysema.query.grammar.types;
+
+/**
+ * CollectionType provides
+ *
+ * @author tiwe
+ * @version $Id$
+ */
+public interface CollectionType<D>{ }
\ No newline at end of file
diff --git a/querydsl-core/src/main/java/com/mysema/query/grammar/types/Expr.java b/querydsl-core/src/main/java/com/mysema/query/grammar/types/Expr.java
index 56168dcd2..4c9080af8 100644
--- a/querydsl-core/src/main/java/com/mysema/query/grammar/types/Expr.java
+++ b/querydsl-core/src/main/java/com/mysema/query/grammar/types/Expr.java
@@ -29,8 +29,6 @@ public abstract class Expr<D> {
         public Boolean or(Boolean right) {return IntGrammar.or(this, right);}
     }
     
-    public interface CollectionType<D>{ }
-    
     public static abstract class Comparable<D extends java.lang.Comparable<D>> extends Literal<D>{
         public Comparable(Class<D> type) {super(type);}
         public Boolean after(D right) {return IntGrammar.after(this,right);}
diff --git a/querydsl-core/src/main/java/com/mysema/query/grammar/types/IntGrammar.java b/querydsl-core/src/main/java/com/mysema/query/grammar/types/IntGrammar.java
index c538eda9b..4a2f3583f 100644
--- a/querydsl-core/src/main/java/com/mysema/query/grammar/types/IntGrammar.java
+++ b/querydsl-core/src/main/java/com/mysema/query/grammar/types/IntGrammar.java
@@ -13,7 +13,6 @@ import static com.mysema.query.grammar.types.Factory.createString;
 import com.mysema.query.grammar.Ops;
 import com.mysema.query.grammar.Order;
 import com.mysema.query.grammar.OrderSpecifier;
-import com.mysema.query.grammar.types.Expr.CollectionType;
 
 /**
  * InternalGrammar provides
diff --git a/querydsl-core/src/main/java/com/mysema/query/grammar/types/Path.java b/querydsl-core/src/main/java/com/mysema/query/grammar/types/Path.java
index d76212b20..4e91677ec 100644
--- a/querydsl-core/src/main/java/com/mysema/query/grammar/types/Path.java
+++ b/querydsl-core/src/main/java/com/mysema/query/grammar/types/Path.java
@@ -24,7 +24,7 @@ public interface Path<C> {
     Expr.Boolean isnotnull();
     Expr.Boolean isnull();
             
-    public static class Boolean extends Expr.Boolean implements Simple<java.lang.Boolean>{
+    public static class Boolean extends Expr.Boolean implements Path<java.lang.Boolean>{
         private final PathMetadata<java.lang.String> metadata;
         public Boolean(PathMetadata<java.lang.String> metadata) {
             this.metadata = metadata;
@@ -34,14 +34,14 @@ public interface Path<C> {
         public Expr.Boolean isnull() {return IntGrammar.isnull(this);}          
     }
         
-    public interface Collection<D> extends Path<java.util.Collection<D>>, Expr.CollectionType<D>{
+    public interface Collection<D> extends Path<java.util.Collection<D>>, CollectionType<D>{
         Expr<D> get(Expr<Integer> index);        
         Expr<D> get(int index);
         Class<D> getElementType();
         Expr.Comparable<Integer> size();
     }
     
-    public static class Comparable<D extends java.lang.Comparable<D>> extends Expr.Comparable<D> implements Simple<D>{
+    public static class Comparable<D extends java.lang.Comparable<D>> extends Expr.Comparable<D> implements Path<D>{
         private final PathMetadata<?> metadata;
         public Comparable(Class<D> type, PathMetadata<?> metadata) {
             super(type);
@@ -60,17 +60,16 @@ public interface Path<C> {
             this.type = type;
             this.metadata = metadata;
         }        
-        public Expr.Literal<D> get(Expr<Integer> index) {
-            return new Path.Literal<D>(type, forListAccess(this, index));
+        public Expr.Simple<D> get(Expr<Integer> index) {
+            return new Path.Simple<D>(type, forListAccess(this, index));
         }
-        public Expr.Literal<D> get(int index) {
-            return new Path.Literal<D>(type, forListAccess(this, index));
+        public Expr.Simple<D> get(int index) {
+            return new Path.Simple<D>(type, forListAccess(this, index));
         }
         public PathMetadata<?> getMetadata() {return metadata;}
         public Expr.Boolean isnotnull() {return IntGrammar.isnotnull(this);}
         public Expr.Boolean isnull() {return IntGrammar.isnull(this);}
         public Expr.Comparable<Integer> size() { 
-//            return IntGrammar.size(this);
             return new Path.Comparable<Integer>(Integer.class, forSize(this));
         }
         public Class<D> getElementType() {return type;}
@@ -86,11 +85,11 @@ public interface Path<C> {
             this.valueType = valueType;
             this.metadata = metadata;
         }
-        public Expr.Literal<V> get(Expr<K> key) { 
-            return new Path.Literal<V>(valueType, forMapAccess(this, key));
+        public Expr.Simple<V> get(Expr<K> key) { 
+            return new Path.Simple<V>(valueType, forMapAccess(this, key));
         }
-        public Expr.Literal<V> get(K key) { 
-            return new Path.Literal<V>(valueType, forMapAccess(this, key));
+        public Expr.Simple<V> get(K key) { 
+            return new Path.Simple<V>(valueType, forMapAccess(this, key));
         }
         public PathMetadata<?> getMetadata() {return metadata;}
         public Expr.Boolean isnotnull() {return IntGrammar.isnotnull(this);}
@@ -121,8 +120,8 @@ public interface Path<C> {
         protected <A> EntityCollection<A> _entitycol(java.lang.String path,Class<A> type) {
             return new EntityCollection<A>(type, forProperty(this, path));
         }
-        protected <A> Expr.Literal<A> _simple(java.lang.String path, Class<A> type){
-            return new Path.Literal<A>(type, forProperty(this, path));
+        protected <A> Expr.Simple<A> _simple(java.lang.String path, Class<A> type){
+            return new Path.Simple<A>(type, forProperty(this, path));
         }
         protected <A> ComponentCollection<A> _simplecol(java.lang.String path,Class<A> type) {
             return new ComponentCollection<A>(type, forProperty(this, path));
@@ -198,14 +197,10 @@ public interface Path<C> {
         Class<K> getKeyType();
         Class<V> getValueType();
     }
-    
-    public interface Simple<D> extends Path<D>{
-        Expr<D> as(java.lang.String to);              
-    }
-    
-    public static class Literal<D> extends Expr.Literal<D> implements Simple<D>{
+        
+    public static class Simple<D> extends Expr.Simple<D> implements Path<D>{
         private final PathMetadata<?> metadata;
-        public <T> Literal(Class<D> type, PathMetadata<?> metadata) {
+        public <T> Simple(Class<D> type, PathMetadata<?> metadata) {
             super(type);
             this.metadata = metadata;
         }
@@ -214,7 +209,7 @@ public interface Path<C> {
         public Expr.Boolean isnull() {return IntGrammar.isnull(this);}
     }
     
-    public static class String extends Expr.String implements Simple<java.lang.String>{
+    public static class String extends Expr.String implements Path<java.lang.String>{
         private final PathMetadata<java.lang.String> metadata;
         public String(PathMetadata<java.lang.String> metadata) {
             this.metadata = metadata;
diff --git a/querydsl-core/src/main/java/com/mysema/query/grammar/types/Visitor.java b/querydsl-core/src/main/java/com/mysema/query/grammar/types/Visitor.java
index 77d140cf4..1f74261f0 100644
--- a/querydsl-core/src/main/java/com/mysema/query/grammar/types/Visitor.java
+++ b/querydsl-core/src/main/java/com/mysema/query/grammar/types/Visitor.java
@@ -103,8 +103,6 @@ public abstract class Visitor<T extends Visitor<T>> {
     
     protected abstract void visit(Path.Simple<?> expr);
     
-    protected abstract void visit(Path.Literal<?> expr);
-
     protected abstract void visit(Path.String expr);
     
 }
diff --git a/querydsl-core/src/main/java/com/mysema/query/grammar/types/VisitorAdapter.java b/querydsl-core/src/main/java/com/mysema/query/grammar/types/VisitorAdapter.java
index 19a6c87ba..32da97af3 100644
--- a/querydsl-core/src/main/java/com/mysema/query/grammar/types/VisitorAdapter.java
+++ b/querydsl-core/src/main/java/com/mysema/query/grammar/types/VisitorAdapter.java
@@ -87,10 +87,6 @@ public abstract class VisitorAdapter<V extends VisitorAdapter<V>> extends Visito
         visit((Path<?>) expr);
     }
     @Override
-    protected void visit(Path.Literal<?> expr) {
-        visit((Path<?>) expr);
-    }
-    @Override
     protected void visit(Path.String expr) {
         visit((Path<?>) expr);
     }
diff --git a/querydsl-core/src/test/java/com/mysema/query/grammar/VisitorTest.java b/querydsl-core/src/test/java/com/mysema/query/grammar/VisitorTest.java
index f251a341f..4ed28c1f6 100644
--- a/querydsl-core/src/test/java/com/mysema/query/grammar/VisitorTest.java
+++ b/querydsl-core/src/test/java/com/mysema/query/grammar/VisitorTest.java
@@ -23,13 +23,6 @@ public class VisitorTest {
     
     @Test
     public void testIteration() throws SecurityException, NoSuchMethodException{
-//        for (Class<?> innerType : Types.class.getClasses()){
-//            if (!innerType.isInterface()
-//                    && Expr.class.isAssignableFrom(innerType)
-//                    && !innerType.getSimpleName().startsWith("Expr")){                
-//                Visitor.class.getDeclaredMethod("visit", innerType);
-//            }
-//        }
         List<Class<?>> types = new ArrayList<Class<?>>();
         types.addAll(Arrays.asList(Alias.class.getClasses()));
         types.addAll(Arrays.asList(Operation.class.getClasses()));
diff --git a/querydsl-core/src/test/java/com/mysema/query/grammar/types/TypesTest.java b/querydsl-core/src/test/java/com/mysema/query/grammar/types/TypesTest.java
new file mode 100644
index 000000000..5a797c000
--- /dev/null
+++ b/querydsl-core/src/test/java/com/mysema/query/grammar/types/TypesTest.java
@@ -0,0 +1,43 @@
+package com.mysema.query.grammar.types;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+
+/**
+ * TypesTest provides
+ *
+ * @author tiwe
+ * @version $Id$
+ */
+public class TypesTest {
+    
+    @Test
+    public void testAlias(){
+        for (Class<?> cl : Alias.class.getClasses()){
+            assertTrue(cl.getName(),Alias.class.isAssignableFrom(cl));
+            if (!cl.isInterface()){                
+                assertTrue(cl.getName(),Expr.class.isAssignableFrom(cl));    
+            }            
+        }
+    }
+    
+    @Test
+    public void testExpr(){
+        for (Class<?> cl : Expr.class.getClasses()){
+            assertTrue(cl.getName(),Expr.class.isAssignableFrom(cl));
+        }
+    }
+    
+    @Test
+    public void testPath(){
+        for (Class<?> cl : Path.class.getClasses()){
+            assertTrue(cl.getName(),Path.class.isAssignableFrom(cl));
+            if (!cl.isInterface()){         
+                assertTrue(cl.getName(),Expr.class.isAssignableFrom(cl));    
+            }            
+        }
+    }
+
+}