2 files changed, 9 insertions, 5 deletions
diff --git a/chapter11/src/main/java/com/seaofnodes/simple/node/DivNode.java b/chapter11/src/main/java/com/seaofnodes/simple/node/DivNode.java
index ba06d037..08ce70b8 100644
--- a/chapter11/src/main/java/com/seaofnodes/simple/node/DivNode.java
+++ b/chapter11/src/main/java/com/seaofnodes/simple/node/DivNode.java
@@ -32,7 +32,12 @@ public class DivNode extends Node {
     }
 
     @Override
-    public Node idealize() { return null; }
+    public Node idealize() {
+        // Div of 1.
+        if( in(2)._type.isConstant() && in(2)._type instanceof TypeInteger i && i.value()==1 )
+            return in(1);
+        return null;
+    }
 
     @Override Node copy(Node lhs, Node rhs) { return new DivNode(lhs,rhs); }
 }
diff --git a/chapter11/src/main/java/com/seaofnodes/simple/node/SubNode.java b/chapter11/src/main/java/com/seaofnodes/simple/node/SubNode.java
index 7137f38e..128678a7 100644
--- a/chapter11/src/main/java/com/seaofnodes/simple/node/SubNode.java
+++ b/chapter11/src/main/java/com/seaofnodes/simple/node/SubNode.java
@@ -27,15 +27,14 @@ public class SubNode extends Node {
             if (i0.isConstant() && i1.isConstant())
                 return TypeInteger.constant(i0.value()-i1.value());
         }
+        // Sub of same is 0
+        if( in(1)==in(2) )
+            return TypeInteger.ZERO;
         return in(1)._type.meet(in(2)._type);
     }
 
     @Override
     public Node idealize() {
-        // Sub of same is 0
-        if( in(1)==in(2) )
-            return Parser.ZERO;
-
         // x - (-y) is x+y
         if( in(2) instanceof MinusNode minus )
             return new AddNode(in(1),minus.in(1));