Chapter renumber, and split ch 17

Renumber chapters 10a, 10b, 11, 12, 13, 14 -> 10, 11, 13, 12, [11,14].
Split ch 17 into a 17a and 17b; shuffle around im/mutable syntax to be consistent, and present it more slowly.
THe new immutable syntax is pushed through all later chapters

16 files changed, 349 insertions, 773 deletions

diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter01Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter01Test.java
index c10dc510..89882b2f 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter01Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter01Test.java
@@ -15,7 +15,7 @@ public class Chapter01Test {
         StartNode start = Parser.START;
         ReturnNode ret = (ReturnNode)stop.in(0);
 
-        assertTrue(ret.ctrl() instanceof CProjNode);
+        assertTrue(ret.ctrl() instanceof ProjNode);
         Node expr = ret.expr();
         if( expr instanceof ConstantNode con ) {
             assertEquals(start,con.in(0));
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter04Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter04Test.java
index 14d31245..edc62f50 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter04Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter04Test.java
@@ -83,7 +83,7 @@ public class Chapter04Test {
         Parser parser = new Parser("return arg; ");
         StopNode stop = parser.parse();
         ReturnNode ret = stop.ret();
-        assertTrue(ret.in(0) instanceof CProjNode);
+        assertTrue(ret.in(0) instanceof ProjNode);
         assertTrue(ret.in(1) instanceof ProjNode);
         assertEquals(1, ((ProjNode)ret.in(1))._idx);
         assertTrue(ret.in(2) instanceof ProjNode);
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter05Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter05Test.java
index 7beeb4d9..97cd9940 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter05Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter05Test.java
@@ -22,7 +22,7 @@ else {
 
 return a;""");
         StopNode ret = parser.parse().iterate();
-        assertEquals("return Phi(Region21,(arg+2),(arg-3));", ret.toString());
+        assertEquals("return Phi(Region19,(arg+2),(arg-3));", ret.toString());
     }
 
     @Test
@@ -37,7 +37,7 @@ if (arg == 1) {
 }
 return c;""", TypeInteger.BOT);
         StopNode ret = parser.parse().iterate();
-        assertEquals("return Phi(Region19,4,3);", ret.toString());
+        assertEquals("return Phi(Region18,4,3);", ret.toString());
     }
 
     @Test
@@ -65,7 +65,7 @@ else
     b=a+1;
 return a+b;""");
         StopNode ret = parser.parse().iterate();
-        assertEquals("return ((arg*2)+Phi(Region24,2,3));", ret.toString());
+        assertEquals("return ((arg*2)+Phi(Region22,2,3));", ret.toString());
     }
 
     @Test
@@ -80,7 +80,7 @@ else
     a=b+1;
 return a+b;""");
         StopNode ret = parser.parse().iterate();
-        assertEquals("return ((Phi(Region35,(arg*2),arg)+arg)+Phi(Region,4,5));", ret.toString());
+        assertEquals("return ((Phi(Region33,(arg*2),arg)+arg)+Phi(Region,4,5));", ret.toString());
     }
 
     @Test
@@ -100,7 +100,7 @@ else
 return a;
 """, TypeInteger.BOT);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region39,Phi(Region25,2,3),Phi(Region37,4,5));", stop.toString());
+        assertEquals("return Phi(Region37,Phi(Region23,2,3),Phi(Region35,4,5));", stop.toString());
     }
 
     @Test
@@ -116,7 +116,7 @@ if( arg==0 )
 return arg+a+b;
 """, TypeInteger.BOT);
         StopNode stop = parser.parse();
-        assertEquals("return ((arg+Phi(Region16,1,0))+Phi(Region31,2,0));", stop.toString());
+        assertEquals("return ((arg+Phi(Region16,1,0))+Phi(Region32,2,0));", stop.toString());
     }
 
     @Test
@@ -130,7 +130,7 @@ if( arg==1 )
 }
 return a;""");
         StopNode ret = parser.parse().iterate();
-        assertEquals("return (arg==Phi(Region19,3,2));", ret.toString());
+        assertEquals("return (arg==Phi(Region18,3,2));", ret.toString());
     }
 
     @Test
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter06Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter06Test.java
index df0f2848..9af11b68 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter06Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter06Test.java
@@ -17,7 +17,7 @@ return 1;
 """);
         StopNode stop = parser.parse().iterate();
         assertEquals("return 2;", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -46,7 +46,7 @@ return a;
 """);
         StopNode stop = parser.parse().iterate();
         assertEquals("return 2;", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -65,7 +65,7 @@ else
     b=5;
 return b;""", TypeInteger.BOT);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region40,42,5);", stop.toString());
+        assertEquals("return Phi(Region38,42,5);", stop.toString());
     }
 
     @Test
@@ -84,7 +84,7 @@ else
     b=5;
 return b;""", TypeInteger.BOT);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region33,2,5);", stop.toString());
+        assertEquals("return Phi(Region31,2,5);", stop.toString());
     }
 
     @Test
@@ -144,7 +144,7 @@ else
 return a;
 """, TypeInteger.BOT);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region44,3,Phi(Region42,4,5));", stop.toString());
+        assertEquals("return Phi(Region42,3,Phi(Region40,4,5));", stop.toString());
     }
 
     @Test
@@ -251,7 +251,7 @@ if( arg ) {
 return a+b+c;
 """);
         StopNode ret = parser.parse().iterate();
-        assertEquals("return (Phi(Region39,Phi(Region26,2,3),0)+Phi(Region,3,1));", ret.toString());
+        assertEquals("return (Phi(Region39,Phi(Region24,2,3),0)+Phi(Region,3,1));", ret.toString());
     }
 
 
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter07Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter07Test.java
index 222982e7..ff0ca599 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter07Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter07Test.java
@@ -18,8 +18,8 @@ public class Chapter07Test {
                 return arg;
                 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop9,arg,(Phi_arg+1));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop7,arg,(Phi_arg+1));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -35,7 +35,7 @@ if(arg){}else{
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region27,1,Phi(Loop16,1,(Phi_a+1)));", stop.toString());
+        assertEquals("return Phi(Region25,1,Phi(Loop14,1,(Phi_a+1)));", stop.toString());
     }
 
     @Test
@@ -55,7 +55,7 @@ while(i < arg) {
 return sum;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop11,0,Phi(Loop23,Phi_sum,(Phi_sum+Phi(Loop,0,(Phi_j+1)))));", stop.toString());
+        assertEquals("return Phi(Loop9,0,Phi(Loop21,Phi_sum,(Phi_sum+Phi(Loop,0,(Phi_j+1)))));", stop.toString());
     }
 
     @Test
@@ -71,8 +71,8 @@ while(a < 10) {
 return b;
 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop11,2,Phi(Region30,Phi_b,4));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop9,2,Phi(Region28,Phi_b,4));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -90,8 +90,8 @@ while(a < 10) {
 return b;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop11,2,(Phi(Region30,Phi_b,4)+1));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop9,2,(Phi(Region28,Phi_b,4)+1));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
 
@@ -107,8 +107,8 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop10,1,(Phi_a+3));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop8,1,(Phi_a+3));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -123,8 +123,8 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop10,1,(Phi_a+3));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop8,1,(Phi_a+3));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -136,8 +136,8 @@ while(arg) a = 2;
 return a;
 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop10,1,2);", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop8,1,2);", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -149,8 +149,8 @@ while(arg) a = 2;
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop10,1,2);", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop8,1,2);", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -165,8 +165,8 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop10,1,(Phi_a+3));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop8,1,(Phi_a+3));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -181,8 +181,8 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop10,1,(Phi_a+3));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop8,1,(Phi_a+3));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -198,8 +198,8 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop11,1,(Phi_a+3));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop9,1,(Phi_a+3));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -215,8 +215,8 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop11,1,(Phi_a+3));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop9,1,(Phi_a+3));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
 }
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter08Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter08Test.java
index 8c644977..02c3a301 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter08Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter08Test.java
@@ -2,6 +2,7 @@ package com.seaofnodes.simple;
 
 import com.seaofnodes.simple.evaluator.Evaluator;
 import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.TypeInteger;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -23,7 +24,7 @@ while(arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region37,Phi(Region27,Phi(Loop9,arg,(Phi_arg+1)),Add),Add);", stop.toString());
+        assertEquals("return Phi(Region38,Phi(Region26,Phi(Loop7,arg,(Phi_arg+1)),Add),Add);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof RegionNode);
         Assert.assertEquals(5L, Evaluator.evaluate(stop, 1));
         Assert.assertEquals(10L, Evaluator.evaluate(stop, 6));
@@ -46,8 +47,8 @@ while(arg < 10) {
 return a;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop10,1,Phi(Region42,Phi_a,(Phi_a+1)));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop8,1,Phi(Region45,Phi_a,(Phi_a+1)));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
 
@@ -65,7 +66,7 @@ while(arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region35,Phi(Loop9,arg,(Phi_arg+1)),Add);", stop.toString());
+        assertEquals("return Phi(Region36,Phi(Loop7,arg,(Phi_arg+1)),Add);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof RegionNode);
     }
 
@@ -81,7 +82,7 @@ while(arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region27,Phi(Loop9,arg,(Phi_arg+1)),Add);", stop.toString());
+        assertEquals("return Phi(Region26,Phi(Loop7,arg,(Phi_arg+1)),Add);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof RegionNode);
     }
 
@@ -100,8 +101,8 @@ while(arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop9,arg,(Phi_arg+1));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop7,arg,(Phi_arg+1));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
 
@@ -117,8 +118,8 @@ while(arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop9,arg,(Phi_arg+1));", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode);
+        assertEquals("return Phi(Loop7,arg,(Phi_arg+1));", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode);
     }
 
     @Test
@@ -185,7 +186,7 @@ while(arg < 10) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region30,Phi(Loop10,1,(Phi_a+1)),Add);", stop.toString());
+        assertEquals("return Phi(Region29,Phi(Loop8,1,(Phi_a+1)),Add);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof RegionNode);
     }
 
@@ -201,8 +202,8 @@ while(1) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return (Phi(Loop10,1,Add)+1);", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof CProjNode prj && prj._idx==1 );
+        assertEquals("return (Phi(Loop8,1,Add)+1);", stop.toString());
+        assertTrue(stop.ret().ctrl() instanceof ProjNode prj && prj._idx==1 );
     }
 
 }
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter09Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter09Test.java
index 49ee75a2..b1fdc459 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter09Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter09Test.java
@@ -5,6 +5,7 @@ import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 import org.junit.Assert;
+import org.junit.BeforeClass;
 import org.junit.Test;
 import org.junit.Ignore;
 
@@ -69,7 +70,7 @@ while (arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop10,arg,(Phi_arg+2));", stop.toString());
+        assertEquals("return Phi(Loop8,arg,(Phi_arg+2));", stop.toString());
         Assert.assertEquals(11L, Evaluator.evaluate(stop, 1));
     }
 
@@ -86,7 +87,7 @@ while (arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop11,arg,(Phi_arg+4));", stop.toString());
+        assertEquals("return Phi(Loop9,arg,(Phi_arg+4));", stop.toString());
         Assert.assertEquals(13L, Evaluator.evaluate(stop, 1));
     }
 
@@ -115,7 +116,7 @@ while (arg) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop17,arg,(Phi_arg+1));", stop.toString());
+        assertEquals("return Phi(Loop15,arg,(Phi_arg+1));", stop.toString());
     }
 
     @Test
@@ -133,7 +134,7 @@ while(v1+arg) {
 }
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("Stop[ return 0; return 0; ]", stop.toString());
+        assertEquals("return 0;", stop.toString());
     }
 
     @Test
@@ -185,7 +186,7 @@ while(arg) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop12,0,(-(Phi_a+3)));", stop.toString());
+        assertEquals("return Phi(Loop10,0,(-(Phi_a+3)));", stop.toString());
     }
 
     @Test
@@ -199,7 +200,7 @@ int v0=0!=0<-0;
 return -0+0+0;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return 0;", stop.toString());
+        assertEquals("Stop[ ]", stop.toString());
     }
 
 
@@ -226,7 +227,7 @@ while(1) {
 }
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return 0;", stop.toString());
+        assertEquals("Stop[ ]", stop.toString());
     }
 
     @Test
@@ -248,17 +249,16 @@ while(1) {
 return 0!=0;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return 0;", stop.toString());
+        assertEquals("Stop[ ]", stop.toString());
     }
 
     @Test
     public void testFuzz6() {
-        Parser parser = new Parser(
-"""
+        Parser parser = new Parser("""
 int v0=0;
 while(0==1) while(v0)
         v0=1+v0;
-""");
+                                   """);
         StopNode stop = parser.parse().iterate();
         assertEquals("return 0;", stop.toString());
     }
@@ -276,14 +276,14 @@ while(1)
 return v1+v0;
                                    """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return 0;", stop.toString());
+        assertEquals("Stop[ ]", stop.toString());
     }
 
     @Test
     public void testFuzz8() {
         Parser parser = new Parser("while(arg) arg = arg - 1;  return arg;");
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop9,arg,(Phi_arg-1));", stop.toString());
+        assertEquals("return Phi(Loop7,arg,(Phi_arg-1));", stop.toString());
     }
 
     @Test
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter10Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter10Test.java
index 38aceb84..55574c13 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter10Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter10Test.java
@@ -169,7 +169,7 @@ while (arg) {
 return bar.a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop12,0,(Phi_a+2));", stop.toString());
+        assertEquals("return Phi(Loop11,0,(Phi_a+2));", stop.toString());
     }
 
     @Test
@@ -221,7 +221,7 @@ if( bar ) bar.a = 1;
 return bar;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region17,null,new Bar);", stop.toString());
+        assertEquals("return Phi(Region31,(*void)Phi(Region18,null,new Bar),null);", stop.toString());
     }
 
     @Test
@@ -237,7 +237,7 @@ else bar.a = 1;
 return rez;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region35,4,3);", stop.toString());
+        assertEquals("return Phi(Region37,4,3);", stop.toString());
     }
 
     @Test
@@ -254,8 +254,7 @@ while(arg) {
 return ret;
 """);
         try { parser.parse().iterate(); fail(); }
-        catch( Exception e ) {
-            assertEquals("Might be null accessing 'v0'", e.getMessage()); }
+        catch( Exception e ) { assertEquals("Might be null accessing 'v0'", e.getMessage()); }
     }
 
     @Test
@@ -307,12 +306,11 @@ while(arg) {
     v0.v0 = arg;
     arg = arg-1;
     if (arg==5) ret=v0;
-
 }
 return ret;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop12,new s0,Phi(Region34,new s0,Phi_ret));", stop.toString());
+        assertEquals("return Phi(Loop11,new s0,Phi(Region35,new s0,Phi_ret));", stop.toString());
     }
 
     @Test
@@ -329,7 +327,7 @@ while(arg) {
 return ret;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop15,new s0,Phi(Region35,new s0,Phi_ret));", stop.toString());
+        assertEquals("return Phi(Loop15,new s0,Phi(Region36,new s0,Phi_ret));", stop.toString());
     }
 
 
@@ -346,7 +344,7 @@ while(arg < 10) {
 return ret;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop12,new s0,Phi(Region32,new s0,Phi_ret));", stop.toString());
+        assertEquals("return Phi(Loop11,new s0,Phi(Region33,new s0,Phi_ret));", stop.toString());
     }
 
     @Test
@@ -464,6 +462,7 @@ return 0;
         assertEquals("return 0;", stop.toString());
     }
 
+
     @Test public void testReadBeforeStores() {
         var stop = new Parser("""
             struct S { int x; int y; }
@@ -550,8 +549,8 @@ return 0;
             if (arg) s.x=arg+1; else s.x=arg+2;
             return s;
             """).parse().iterate();
-        // These chapters still bind struct Stores to branch control.
-        assertEquals(3,countMemoryNodes(stop,StoreNode.class,new BitSet()));
+        // The initializing slice also remains live as the aggregate default.
+        assertEquals(2,countMemoryNodes(stop,StoreNode.class,new BitSet()));
         assertEquals(2L,((Evaluator.Obj)Evaluator.evaluate(stop,0)).fields()[0]);
         assertEquals(4L,((Evaluator.Obj)Evaluator.evaluate(stop,3)).fields()[0]);
     }
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter10bTest.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter10bTest.java
deleted file mode 100644
index 6f094cfb..00000000
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter10bTest.java
+++ /dev/null
@@ -1,64 +0,0 @@
-package com.seaofnodes.simple;
-
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.evaluator.Evaluator;
-import org.junit.Test;
-import static org.junit.Assert.*;
-
-public class Chapter10bTest {
-    @Test public void testIndependentField() {
-        var stop = new Parser("""
-            struct S { int x; int y; }
-            S s = new S;
-            s.x = 42;
-            while (arg > 0) { s.y = s.y + arg; arg = arg - 1; }
-            return s.x;
-            """).parse().iterate();
-        assertEquals("return 42;",stop.toString());
-        assertEquals(42L,Evaluator.evaluate(stop,5));
-        assertNull(stop.walk(n -> n instanceof LoadNode ? n : null));
-    }
-
-    @Test public void testParallelMemoryPhis() {
-        var stop = new Parser("""
-            struct S { int x; int y; int z; }
-            S a = new S; S b = new S;
-            S p = a; if (arg) p = b;
-            while (arg > 0) {
-                a.x = p.x + arg;
-                a.y = p.y + 2;
-                a.z = p.z + 3;
-                arg = arg - 1;
-            }
-            return a;
-            """).parse().iterate();
-        int[] phis = {0};
-        stop.walk(n -> {
-            if (n instanceof MemPhiNode) phis[0]++;
-            if (n instanceof MemMergeNode m && m.in(1) instanceof BulkMemPhiNode b)
-                for(int a=b._aliases.nextSetBit(0); a>=0; a=b._aliases.nextSetBit(a+1))
-                    assertTrue(a<m.nIns() && m.in(a)!=null);
-            assertFalse(n instanceof PhiNode && n.isMem() &&
-                !(n instanceof MemPhiNode) && !(n instanceof BulkMemPhiNode));
-            return null;
-        });
-        assertTrue(phis[0]>=3);
-        assertArrayEquals(new Object[]{1L,2L,3L},((Evaluator.Obj)Evaluator.evaluate(stop,4)).fields());
-    }
-
-    @Test public void testLateSliceWorklist() throws ReflectiveOperationException {
-        // Seed 97 exposed a store selecting a bulk predecessor without queuing
-        // it. Keep both the worklist assertion and the final heap check.
-        for (int seed : new int[]{0,97,123,456}) {
-            var parser = new Parser(Chapter10Test.NESTED_MEMORY);
-            var field = IterPeeps.class.getDeclaredField("WORK");
-            field.setAccessible(true);
-            Object work = field.get(null);
-            field = work.getClass().getDeclaredField("_R");
-            field.setAccessible(true);
-            ((java.util.Random)field.get(work)).setSeed(seed);
-            var stop = parser.parse().iterate();
-            assertArrayEquals(new Object[]{9L,25L,17L},((Evaluator.Obj)Evaluator.evaluate(stop,4)).fields());
-        }
-    }
-}
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter11Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter11Test.java
index 0e492591..5f92c9c1 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter11Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter11Test.java
@@ -1,532 +1,64 @@
 package com.seaofnodes.simple;
 
-
+import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.evaluator.Evaluator;
-import com.seaofnodes.simple.node.StopNode;
 import org.junit.Test;
-
-
-import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.*;
 
 public class Chapter11Test {
-
-    // A placeholder test used to rapidly rotate through fuzzer produced issues
-    @Test
-    public void testFuzzer() {
-        Parser parser = new Parser(
-"""
-while(-----arg) {
-    while(-arg) {
-        while(-----arg*---0) {
-                int N=--false==false<--arg;
-                while(N<-4==N) {
-                    N=N+N;
-                }
-            }
-        {
-            int kzEl_r7EYz=3*----0!=-arg<(37*--97!=0/arg==arg)<=-(--arg!=0);
-            while(kzEl_r7EYz<---1) {
-                kzEl_r7EYz=kzEl_r7EYz+kzEl_r7EYz*arg>=24;
-                if(7) continue;
-                kzEl_r7EYz=false;
-                if(-kzEl_r7EYz+arg<-3) continue;
-                else {
-                    while(kzEl_r7EYz) continue;
-                    arg=----3;
-                    kzEl_r7EYz=-(-----arg*1>-kzEl_r7EYz);
-                    int v2uF_4ba=9;
-                }
-            }
-        }
-        int pjcp7rv=arg;
-        {
-            int m2ya3=--arg-pjcp7rv;
-            while(m2ya3<-----pjcp7rv>=pjcp7rv+--pjcp7rv!=---pjcp7rv!=-arg<---(-m2ya3)>m2ya3<=-----true>14!=--m2ya3) {
-                m2ya3=m2ya3+-(--0<=false<pjcp7rv/arg<=-true);
-                while((--m2ya3)<--arg<-----arg*false!=arg<pjcp7rv*arg) {
-                    pjcp7rv=-3+-arg;
-                    break;
-                }
-                while(-3) {
-                    while(67+0-61) m2ya3=m2ya3;
-                    if(----pjcp7rv==---(---arg)) pjcp7rv=0!=-23;
-                    else pjcp7rv=----89;
-                    while(m2ya3!=m2ya3<pjcp7rv) m2ya3=1;
-                    while(--arg<=pjcp7rv) pjcp7rv=-32<=-m2ya3+62;
-                }
-                break;
-            }
-        }
-        {
-            int arg=-1<-9!=(-arg>=-pjcp7rv>=arg<=arg);
-            while(arg<-arg) {
-                arg=arg+--arg;
-                {
-                    while((--93)--pjcp7rv*-pjcp7rv+arg) arg=0-(6>=(--(---41/(0))!=--pjcp7rv)>=---2*33);
-                    pjcp7rv=11;
-                    int c=pjcp7rv;
-                    if(--107) break;
-                    else break;
-                }
-            }
-        }
-        pjcp7rv=pjcp7rv;
-        int aR0Wkua=-pjcp7rv==pjcp7rv;
-        {
-            if(-0!=-0) while(-true) break;
-            else {
-                while(aR0Wkua) pjcp7rv=-0/pjcp7rv;
-                pjcp7rv=pjcp7rv;
-            }
-        }
-    }
-    if(-arg) {
-        {
-            int Isdlt0fr91=0!=arg;
-            while(Isdlt0fr91<-Isdlt0fr91==-Isdlt0fr91+true) {
-                Isdlt0fr91=Isdlt0fr91+-1!=true;
-                if(-arg) if(--arg<=Isdlt0fr91) Isdlt0fr91=-Isdlt0fr91;
-                int i=---arg<---arg!=--40;
-                {
-                    int jVX43Ln4Dm=-(6)==-Isdlt0fr91/----0;
-                    while(jVX43Ln4Dm<--(3-3)) {
-                        jVX43Ln4Dm=jVX43Ln4Dm+-0<25;
-                        i=24<--(jVX43Ln4Dm);
-                    }
-                }
-                i=(arg!=----false>=7);
-                int Te=5>-arg;
-                break;
-            }
-        }
-        arg=arg!=--true/arg;
-        {
-            int UX=arg;
-            while(UX<-3*arg) {
-                UX=UX+arg/-1;
-                arg=-3--(-UX--47<arg==--arg==arg)/arg--UX>=-arg;
-                if(---12) while(-UX) break;
-                break;
-            }
-        }
-        continue;
-    }
-    if(arg) arg=--0;
-    else if(1) continue;
-    int DtTlhjYq=19==arg;
-    {
-        arg=--DtTlhjYq<=(DtTlhjYq/---DtTlhjYq<=-DtTlhjYq);
-        if(---arg) continue;
-        else {
-                int Zsl=40;
-                while(Zsl<--Zsl--false>((Zsl))==Zsl!=--DtTlhjYq-DtTlhjYq-DtTlhjYq) {
-                    Zsl=Zsl+arg;
-                }
-            }
-        if((arg)) if(-DtTlhjYq) {
-            }
-            else while(((2)==3*arg/DtTlhjYq)<=0==---arg) return false;
-        else {
-                int lwbF=arg>=0;
-                while(lwbF<57) {
-                    lwbF=lwbF+--(-arg+lwbF)>=-2>=arg!=arg;
-                    arg=----0+0;
-                    while(49) break;
-                    if(true) DtTlhjYq=-----arg;
-                    DtTlhjYq=0!=-----(0);
-                }
-            }
-        arg=---arg!=DtTlhjYq/--0;
-        DtTlhjYq=-DtTlhjYq/(--arg<arg);
-        if(32) {
-                int q=-DtTlhjYq;
-                while(q<arg*(0*q)/0) {
-                    q=q+DtTlhjYq;
-                    DtTlhjYq=arg;
-                }
-            }
-        else if(--arg) if(15) break;
-                else arg=0==arg<=-55>DtTlhjYq;
-            else {
-            }
-        DtTlhjYq=-0;
-        {
-            while((0)<-arg) DtTlhjYq=-DtTlhjYq;
-        }
-        if(30/--(arg)>=0) DtTlhjYq=-0>=arg;
-        else {
-            int Y2wcIQJ=--DtTlhjYq*---11;
-            if(arg==arg) {
-                Y2wcIQJ=-----Y2wcIQJ;
-                Y2wcIQJ=Y2wcIQJ<7;
-                if(DtTlhjYq) arg=arg;
-                else break;
-                while(-arg!=-31==(false<=-15>=-DtTlhjYq+--6*-----Y2wcIQJ<=---arg!=-Y2wcIQJ<=---0<-arg*--Y2wcIQJ)) DtTlhjYq=arg!=3;
-            }
-            continue;
-        }
-        arg=DtTlhjYq;
-        arg=--3/(---arg)>=80>=-DtTlhjYq<=DtTlhjYq;
-        arg=51+---(-true)!=arg!=----1==-DtTlhjYq;
-        if(11<=arg) if((arg)+79<32+(-arg)) continue;
-            else if(true==DtTlhjYq) break;
-        break;
-    }
-}
-if(arg!=62==arg) {
-    while(---arg) {
-        {
-            int bhmDacPM=arg/arg;
-            while(bhmDacPM<arg) {
-                bhmDacPM=bhmDacPM+80*((-bhmDacPM)/---bhmDacPM>1)<bhmDacPM-2!=7;
-                arg=-0;
-                arg=bhmDacPM>=-arg+-arg;
-                break;
-            }
-        }
-        int arg=true;
-        arg=arg<=arg;
-        {
-            int KlC=30;
-            while(KlC<-2) {
-                KlC=KlC+-1!=25<=-KlC>KlC>----0;
-                int Ij=arg>=-arg<=---10;
-                {
-                    int LAbgurVa2R=-arg!=Ij;
-                    while(LAbgurVa2R<-true) {
-                        LAbgurVa2R=LAbgurVa2R+Ij;
-                        KlC=-LAbgurVa2R;
-                        Ij=42*(-Ij>true);
-                        while(Ij) arg=KlC;
-                        KlC=-----7>-(--KlC<--7)==-LAbgurVa2R;
-                    }
-                }
-                int a=Ij<=-KlC;
-                if(Ij) {
-                    int r1W=a!=-false;
-                }
-                else {
-                    arg=56>=Ij;
-                    while(54) break;
-                    arg=8>=-(a<--Ij)/a>=-a-KlC;
-                }
-                int Yt_T=KlC;
-                arg=KlC;
-            }
+    @Test public void testIndependentField() {
+        var stop = new Parser("""
+            struct S { int x; int y; }
+            S s = new S;
+            s.x = 42;
+            while (arg > 0) { s.y = s.y + arg; arg = arg - 1; }
+            return s.x;
+            """).parse().iterate();
+        assertEquals("return 42;",stop.toString());
+        assertEquals(42L,Evaluator.evaluate(stop,5));
+        assertNull(stop.walk(n -> n instanceof LoadNode ? n : null));
+    }
+
+    @Test public void testParallelMemoryPhis() {
+        var stop = new Parser("""
+            struct S { int x; int y; int z; }
+            S a = new S; S b = new S;
+            S p = a; if (arg) p = b;
+            while (arg > 0) {
+                a.x = p.x + arg;
+                a.y = p.y + 2;
+                a.z = p.z + 3;
+                arg = arg - 1;
+            }
+            return a;
+            """).parse().iterate();
+        int[] phis = {0};
+        stop.walk(n -> {
+            if (n instanceof MemPhiNode) phis[0]++;
+            if (n instanceof MemMergeNode m && m.in(1) instanceof BulkMemPhiNode b)
+                for(int a=b._aliases.nextSetBit(0); a>=0; a=b._aliases.nextSetBit(a+1))
+                    assertTrue(a<m.nIns() && m.in(a)!=null);
+            assertFalse(n instanceof PhiNode && n.isMem() &&
+                !(n instanceof MemPhiNode) && !(n instanceof BulkMemPhiNode));
+            return null;
+        });
+        assertTrue(phis[0]>=3);
+        assertArrayEquals(new Object[]{1L,2L,3L},((Evaluator.Obj)Evaluator.evaluate(stop,4)).fields());
+    }
+
+    @Test public void testLateSliceWorklist() throws ReflectiveOperationException {
+        // Seed 97 exposed a store selecting a bulk predecessor without queuing
+        // it. Keep both the worklist assertion and the final heap check.
+        for (int seed : new int[]{0,97,123,456}) {
+            var parser = new Parser(Chapter10Test.NESTED_MEMORY);
+            var field = IterPeeps.class.getDeclaredField("WORK");
+            field.setAccessible(true);
+            Object work = field.get(null);
+            field = work.getClass().getDeclaredField("_R");
+            field.setAccessible(true);
+            ((java.util.Random)field.get(work)).setSeed(seed);
+            var stop = parser.parse().iterate();
+            assertArrayEquals(new Object[]{9L,25L,17L},((Evaluator.Obj)Evaluator.evaluate(stop,4)).fields());
         }
-        if(----false/--arg/12+-----0) if(-9+-arg) while(arg!=(arg)) arg=--1>=-71-arg!=---(--arg*11+102)/--arg;
-            else if(----arg) continue;
-        if(-arg-arg) {
-            arg=-(-arg)*--(-3)<(-7==-arg----arg);
-            {
-                int arg=arg;
-                while(arg<-0>arg==-arg-(-arg>1+11)) {
-                    arg=arg+6-arg!=--0>---30>=---arg<=arg/(3)+---arg;
-                }
-            }
-            arg=-arg+arg;
-            arg=--47+-arg<1>arg*(-arg==-arg--0>3);
-            arg=(----arg)!=arg+--59;
-            arg=--4+arg==-(arg)-arg;
-        }
-        else {
-            while(--true-----true*-25+-18>arg>=-----(-arg)---13) {
-                arg=-0+--true<false;
-                continue;
-            }
-            arg=true<=arg;
-            break;
-        }
-        arg=arg*22<--(0+-arg);
-        {
-            continue;
-        }
-    }
-    arg=1*---((3<=true)==---2);
-    arg=7+-(-1);
-    return arg+--true;
-}
-else {
-    int o3ypEsewxM=-(---arg);
-    int vzXB=(-(---11<=--o3ypEsewxM>=--0))<=-0/-arg;
-    int L=-arg;
-    int B4mHcrf=---vzXB;
-    int oZWGdzZl=-o3ypEsewxM;
-    int K6tQqa1=11;
-    while(0!=--L) {
-            int sdZfTM=vzXB*true+K6tQqa1;
-            while(sdZfTM<false) {
-                sdZfTM=sdZfTM+arg;
-                sdZfTM=oZWGdzZl;
-                K6tQqa1=-K6tQqa1;
-                arg=---K6tQqa1;
-                while((3+-K6tQqa1)<oZWGdzZl) {
-                    if(-----(-1)) sdZfTM=-false;
-                    {}
-                }
-                K6tQqa1=vzXB!=-(B4mHcrf+-7>false);
-                sdZfTM=vzXB;
-            }
-        }
-    L=false;
-    while(31) B4mHcrf=arg;
-    oZWGdzZl=-0<--oZWGdzZl<=--2;
-    if(K6tQqa1>=20<=46) {
-        if(-1+-L) if(oZWGdzZl) {
-                int wmhv=-----0;
-            }
-        int arg=0;
-        o3ypEsewxM=---(oZWGdzZl);
-        return -oZWGdzZl/0;
-    }
-    else if(arg) {
-            int yKk5=B4mHcrf>=4>K6tQqa1<-B4mHcrf/o3ypEsewxM;
-            return -K6tQqa1;
-        }
-        else {
-            if(---0) {
-                {}
-                {}
-            }
-            return o3ypEsewxM;
-        }
-}
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("Stop[ return 9; return 0; return 0; return 0; return 0; ]", stop.toString());
-    }
-
-
-    @Test
-    public void testPrimes() {
-        Parser parser = new Parser(
-"""
-if( arg < 2 ) return 0;
-int primeCount = 1;
-int prime = 3;
-while( prime <= arg ) {
-    int isPrime = 1;
-    // Check for even case, so the next loop need only check odds
-    if( (prime/2)*2 == prime )
-        continue;
-    // Check odds up to sqrt of prime
-    int j = 3;
-    while( j*j <= prime ) {
-        if( (prime/j)*j == prime ) {
-            isPrime = 0;
-            break;
-        }
-        j = j + 2;
-    }
-    if( isPrime )
-        primeCount = primeCount + 1;
-    prime = prime + 2;
-}
-return primeCount;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("Stop[ return 0; return Phi(Loop20,1,Phi(Region82,Phi_primeCount,Phi(Region77,(Phi_primeCount+1),Phi_primeCount))); ]", stop.toString());
-        assertEquals(0L, Evaluator.evaluate(stop,  1)); // No primes 1 or below
-        assertEquals(1L, Evaluator.evaluate(stop,  2)); // 2
-        assertEquals(2L, Evaluator.evaluate(stop,  3)); // 2, 3
-        assertEquals(2L, Evaluator.evaluate(stop,  4)); // 2, 3
-        assertEquals(3L, Evaluator.evaluate(stop,  5)); // 2, 3, 5
-        assertEquals(4L, Evaluator.evaluate(stop, 10)); // 2, 3, 5, 7
-    }
-
-    @Test
-    public void testAntiDeps1() {
-        Parser parser = new Parser(
-"""
-struct S { int f; }
-S v=new S;
-v.f = 2;
-int i=new S.f;
-i=v.f;
-if (arg) v.f=1;
-return i;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("return .f;", stop.toString());
-    }
-
-    @Test
-    public void testAntiDeps2() {
-        Parser parser = new Parser(
-"""
-struct S { int f; }
-S v = new S;
-S t = new S;
-int i = 0;
-if (arg) {
-    if (arg+1) v = t;
-    i = v.f;
-} else {
-    v.f = 2;
-}
-return i;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region34,.f,0);", stop.toString());
-    }
-
-    @Test
-    public void testAntiDeps3() {
-        Parser parser = new Parser(
-"""
-struct S { int f; }
-S v0 = new S;
-S? v1;
-if (arg) v1 = new S;
-if (v1) {
-    v0.f = v1.f;
-} else {
-    v0.f = 2;
-}
-return v0;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("return new S;", stop.toString());
-    }
-
-
-    @Test
-    public void testAntiDeps4() {
-        Parser parser = new Parser(
-"""
-struct S { int f; }
-S v = new S;
-S t = new S;
-int i = v.f;
-if (arg+1) arg= 0;
-while (arg) v.f = 2;
-return i;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("return .f;", stop.toString());
-    }
-
-    @Test
-    public void testAntiDeps5() {
-        Parser parser = new Parser(
-"""
-struct S { int f; }
-S v = new S;
-while(1) {
-    while(arg+1) { arg=arg-1; }
-    if (arg) break;
-    v.f = 2;
-}
-return v;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("return new S;", stop.toString());
-    }
-
-    @Test
-    public void testAntiDeps6() {
-        Parser parser = new Parser(
-"""
-struct s { int v; }
-s ptr=new s;
-while( -arg )
-  ptr = new s;
-while(1)
-  arg = arg+ptr.v;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("Stop[ return 0; return 0; ]", stop.toString());
-    }
-
-    @Test
-    public void testAntiDeps7() {
-        Parser parser = new Parser(
-"""
-struct S { int f; }
-S v = new S;
-S t = new S;
-int i = v.f;
-while (arg) {
-    v.f = arg;
-    arg = arg-1;
-}
-return i;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("return .f;", stop.toString());
-    }
-
-    @Test
-    public void testAntiDeps8() {
-        Parser parser = new Parser(
-"""
-struct S { int f; }
-S v = new S;
-S t = new S;
-while(arg) {
-    arg=arg-1;
-    int f = v.f;
-    v.f = 2;
-    if (arg) arg = f;
-    else v.f = 3;
-}
-return arg;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop15,arg,Phi(Region39,.f,0));", stop.toString());
-    }
-
-    @Test
-    public void testAntiDeps9() {
-        Parser parser = new Parser(
-"""
-struct S { int f; }
-S v = new S;
-S t = new S;
-if (arg) {
-    v.f=2;
-    int i=t.f;
-    v.f=i;
-}
-return v;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("return new S;", stop.toString());
-    }
-
-    @Test
-    public void testExample2() {
-        Parser parser = new Parser(
-                """
-struct S { int f; }
-S v = new S;
-int i = arg;
-while (arg > 0) {
-    int j = i/3;
-    if (arg == 5)
-        v.f = j;
-    arg = arg - 1;
-}
-return v;
-                """);
-        StopNode stop = parser.parse().iterate();
-        //assertEquals("return new S;", stop.toString());
-    }
-
-    @Test
-    public void testSplit() {
-        Parser parser = new Parser(
-                                   """
-struct S { int f; }
-S s = new S;
-if( arg==0 ) s.f = 1;
-else if (arg == 1) s.f = 1;
-return s.f;
-""");
-        StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region41,1,Phi(Region36,1,0));", stop.toString());
-        assertEquals(1L, Evaluator.evaluate(stop,  0));
-        assertEquals(1L, Evaluator.evaluate(stop,  1));
-        assertEquals(0L, Evaluator.evaluate(stop,  2));
     }
 }
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter12Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter12Test.java
index e577c8c3..0d4f3c97 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter12Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter12Test.java
@@ -2,84 +2,199 @@ package com.seaofnodes.simple;
 
 import com.seaofnodes.simple.evaluator.Evaluator;
 import com.seaofnodes.simple.node.StopNode;
+import com.seaofnodes.simple.type.TypeStruct;
+import com.seaofnodes.simple.type.TypeMemPtr;
+import org.junit.Ignore;
 import org.junit.Test;
-
-
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
 
 public class Chapter12Test {
-    @Test public void testSubZeroFloat() {
-        var stop = new Parser("flt x = arg; return 0-x;").parse().iterate();
-        // Compare strings so +0.0 and -0.0 remain distinct.
-        assertEquals("0.0", Evaluator.evaluate(stop,0).toString());
-        assertEquals("-1.0", Evaluator.evaluate(stop,1).toString());
+
+    @Test
+    public void testLinkedList0() {
+        Parser parser = new Parser(
+"""
+struct LLI { LLI? next; int i; }
+LLI? head = null;
+while( arg ) {
+    LLI x = new LLI;
+    x.next = head;
+    x.i = arg;
+    head = x;
+    arg = arg-1;
+}
+return head.next.i;
+""");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Might be null accessing 'next'",e.getMessage()); }
     }
 
-    @Test public void testDeadNumericReturns() {
-        for( String[] test : new String[][] {
-            {"if(1) return 7; else return 2.5;", "7"},
-            {"if(0) return 7; else return 2.5;", "2.5"},
-            {"return 7; return 2.5;", "7"},
-            {"return 2.5; return 7;", "2.5"}
-        } ) {
-            String src = test[0];
-            var stop = new Parser(src).parse().iterate();
-            assertEquals(src,test[1],com.seaofnodes.simple.evaluator.Evaluator.evaluate(stop,0).toString());
-        }
+    @Test
+    public void testLinkedList1() {
+        Parser parser = new Parser(
+"""
+struct LLI { LLI? next; int i; }
+LLI? head = null;
+while( arg ) {
+    LLI x = new LLI;
+    x.next = head;
+    x.i = arg;
+    head = x;
+    arg = arg-1;
+}
+if( !head ) return 0;
+LLI? next = head.next;
+if( next==null ) return 1;
+return next.i;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("Stop[ return 0; return 1; return .i; ]", stop.toString());
+        assertEquals(2L, Evaluator.evaluate(stop,  3));
     }
 
+    @Test
+    public void testCoRecur() {
+        Parser parser = new Parser(
+"""
+struct Left { int i; Right? f; }
+struct Right { int f; Left? i; }
+Left left = new Left;
+left.i = 17;
+Right right = new Right;
+right.f = 314;
+left.f = right;
+right.i = left;
+return right.i.f.i.i;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 17;", stop.toString());
+    }
 
     @Test
-    public void testJig() {
+    public void testNullReright() {
         Parser parser = new Parser(
 """
-return 3.14;
+struct N { N next; int i; }
+N n = new N;
+return n.next;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return 3.14;", stop.toString());
-        assertEquals(3.14, Evaluator.evaluate(stop,  0));
+        assertEquals("return null;", stop.toString());
     }
 
     @Test
-    public void testFloat() {
+    public void testNullRef1() {
         Parser parser = new Parser(
 """
-return 3.14;
+struct N { N next; int i; }
+N n = new N;
+n.next = new N;
+return n.next;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return 3.14;", stop.toString());
-        assertEquals(3.14, Evaluator.evaluate(stop,  0));
+        assertEquals("return new N;", stop.toString());
     }
 
     @Test
-    public void testSquareRoot() {
+    public void testNullRef2() {
         Parser parser = new Parser(
 """
-flt guess = arg;
-while( 1 ) {
-    flt next = (arg/guess + guess)/2;
-    if( next == guess ) break;
-    guess = next;
-}
-return guess;
+struct N { N next; int i; }
+N n = new N;
+n.next = null;
+return n.next;
+""");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot store null into field *N next",e.getMessage()); }
+    }
+
+
+    @Test
+    public void testNullRef4() {
+        Parser parser = new Parser("-null-5/null-5");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Expected an identifier, found 'null'",e.getMessage()); }
+    }
+
+    @Test public void testNullRef5() {
+        Parser parser = new Parser("return null+42;");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot 'Add' null",e.getMessage()); }
+    }
+
+    @Test
+    public void testEmpty() {
+        Parser parser = new Parser(
+"""
+struct S{};
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop10,(flt)arg,(((ToFloat/Phi_guess)+Phi_guess)/2.0));", stop.toString());
-        assertEquals(3.0, Evaluator.evaluate(stop,  9));
-        assertEquals(1.414213562373095, Evaluator.evaluate(stop,  2));
+        assertEquals("return 0;", stop.toString());
+        assertEquals(0L, Evaluator.evaluate(stop,  0));
+    }
+
+    @Test
+    public void testForwardReright() {
+        Parser parser = new Parser(
+"""
+struct S1 { S2 s; }
+return new S2;
+""");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Unknown struct type 'S2'",e.getMessage()); }
     }
 
     @Test
-    public void testFPOps() {
+    public void testForwardRef1() {
         Parser parser = new Parser(
 """
-flt x = arg;
-return x+1==x;
+struct S1 { S2? s; }
+struct S2 { int x; }
+return new S1.s=new S2;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return ((flt)arg==(ToFloat+1.0));", stop.toString());
-        assertEquals(0L, Evaluator.evaluate(stop, 1));
+        assertEquals("return new S1;", stop.toString());
     }
 
+    @Test
+    public void testcheckNull() {
+        Parser parser = new Parser(
+"""
+struct I {int i;}
+struct P {I pi;}
+P p1 = new P;
+P p2 = new P;
+p2.pi = new I;
+p2.pi.i = 2;
+if (arg) p1 = new P;
+return p1.pi.i + 1;
+""");
+        try { parser.parse().iterate();  fail(); }
+        catch( Exception e ) {  assertEquals("Might be null accessing 'i'",e.getMessage());  }
+    }
+
+
+    @Test
+    public void testShallowRecursiveType() {
+        new Parser("struct LLI { LLI? next; int i; } return 0;").parse().iterate();
+        TypeStruct l1 = (TypeStruct)Parser.TYPES.get("LLI");
+        TypeStruct l0 = ((TypeMemPtr)l1._fields[0]._type)._obj;
+        assertEquals("LLI", l0._name);
+        assertNull(l0._fields);
+        assertEquals(2, l1._fields.length);
+        assertSame(l0, l1.meet(l0));
+        assertSame(l0, l0.dual());
+        assertSame(l0, l0.glb());
+    }
+
+    @Test
+    public void testUnusedForwardReference() {
+        StopNode stop = new Parser("struct Holder { Missing? ref; } Holder h = new Holder; return h.ref;")
+            .parse().iterate();
+        assertEquals("return null;", stop.toString());
+        assertNull(((TypeStruct)Parser.TYPES.get("Missing"))._fields);
+    }
 }
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/FuzzerWrap.java b/chapter12/src/test/java/com/seaofnodes/simple/FuzzerWrap.java
index 52c2a014..019140ad 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/FuzzerWrap.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/FuzzerWrap.java
@@ -29,8 +29,8 @@ public class FuzzerWrap {
             fuzzer.fuzzPeepsRegression(seed);
     }
 
-    @Ignore
     @Test
+    @Ignore
     public void fuzzPeepsLarge() {
         var fuzzer = new Fuzzer();
         for (int i=0; i<1000000; i++)
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/TypeTest.java b/chapter12/src/test/java/com/seaofnodes/simple/TypeTest.java
index f9c580cc..298fc6f8 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/TypeTest.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/TypeTest.java
@@ -36,9 +36,9 @@ public class TypeTest {
         Assert.assertEquals(TypeMem   .BOT, m2.meet(m3));
         Assert.assertEquals(TypeMem   .BOT, m3.meet(m4));
 
-        Assert.assertEquals(TypeMem.BOT, m1.glb());
+        Assert.assertEquals(m1, m1.glb());
         Assert.assertEquals(m1, m1.dual());
-        Assert.assertEquals(TypeMem.TOP, m1.glb().dual());
+        Assert.assertEquals(m1, m1.glb().dual());
 
         TypeMemPtr ptr1 = TypeMemPtr.make(s1);
         Assert.assertEquals(s1, ptr1._obj);
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java b/chapter12/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
index 40a2f78d..ac7c5e09 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
@@ -2,7 +2,10 @@ package com.seaofnodes.simple.evaluator;
 
 import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.type.Field;
+import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.type.TypeMemPtr;
+import com.seaofnodes.simple.type.TypeStruct;
 
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
@@ -77,10 +80,6 @@ public class Evaluator {
         long in2 = vall(div.in(2));
         return in2 == 0 ? 0 : vall(div.in(1)) / in2;
     }
-    private double div(DivFNode div) {
-        double in2 = vald(div.in(2));
-        return in2 == 0 ? 0 : vald(div.in(1)) / in2;
-    }
 
     private Object alloc(NewNode alloc) {
         var type = ((TypeMemPtr)alloc.compute())._obj;
@@ -116,16 +115,10 @@ public class Evaluator {
         if (v instanceof Number n) return n.longValue();
         throw new AssertionError("Not a long " + v);
     }
-    private double vald(Node node) {
-        var v = val(node);
-        if (v instanceof Number n) return n.doubleValue();
-        throw new AssertionError("Not a double " + v);
-    }
 
     private Object cons(ConstantNode cons) {
         var type = cons.compute();
         if (type instanceof TypeInteger i) return i.value();
-        if (type instanceof TypeFloat i) return i.value();
         assert type instanceof TypeMemPtr;
         return null;
     }
@@ -134,30 +127,20 @@ public class Evaluator {
         return switch (node) {
             case ConstantNode cons  -> cons(cons);
             case AddNode      add   -> vall(add.in(1)) + vall(add.in(2));
-            case AddFNode     add   -> vald(add.in(1)) + vald(add.in(2));
-            case BoolNode.EQF eq    -> vald(eq.in(1)) == vald(eq.in(2)) ? 1L : 0L;
-            case BoolNode.LEF le    -> vald(le.in(1)) <= vald(le.in(2)) ? 1L : 0L;
-            case BoolNode.LTF lt    -> vald(lt.in(1)) <  vald(lt.in(2)) ? 1L : 0L;
             case BoolNode.EQ  eq    -> Objects.equals(val(eq.in(1)), val(eq.in(2))) ? 1L : 0L;
             case BoolNode.LE  le    -> vall(le.in(1)) <= vall(le.in(2)) ? 1L : 0L;
             case BoolNode.LT  lt    -> vall(lt.in(1)) <  vall(lt.in(2)) ? 1L : 0L;
             case DivNode      div   -> div(div);
-            case DivFNode     div   -> div(div);
             case MinusNode    minus -> -vall(minus.in(1));
-            case MinusFNode   minus -> -vald(minus.in(1));
             case MulNode      mul   -> vall(mul.in(1)) * vall(mul.in(2));
-            case MulFNode     mul   -> vald(mul.in(1)) * vald(mul.in(2));
             case NotNode      not   -> isTrue(val(not.in(1))) ? 0L : 1L;
             case SubNode      sub   -> vall(sub.in(1)) - vall(sub.in(2));
-            case SubFNode     sub   -> vald(sub.in(1)) - vald(sub.in(2));
             case CastNode     cast  -> val(cast.in(1));
-            case ToFloatNode  cast  -> (double)vall(cast.in(1));
             case LoadNode     load  -> load(load);
             case StoreNode    store -> store(store);
             case MemMergeNode merge -> MEMORY;
             case NewNode      alloc -> alloc(alloc);
-            case CProjNode    cproj -> ((Object[])val(cproj.ctrl()))[cproj._idx];
-            case ProjNode     proj  -> ((Object[])val( proj.in(0) ))[ proj._idx];
+            case ProjNode     proj  -> ((Object[])val(proj.ctrl()))[proj._idx];
             default                 -> throw new AssertionError("Unexpected node " + node);
         };
     }
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java b/chapter12/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
index d16f4300..48ac0562 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
@@ -164,7 +164,7 @@ public class Scheduler {
      * @return true if the node is not XCtrl.
      */
     private static boolean isNotXCtrl(Node node) {
-        return !(node instanceof ConstantNode c && c.compute() == Type.XCONTROL) && !(node instanceof XCtrlNode);
+        return !(node instanceof ConstantNode c && c.compute() == Type.XCONTROL);
     }
 
     /**
@@ -215,7 +215,7 @@ public class Scheduler {
     private void refinePlacement(NodeData data, BasicBlock block) {
         assert !isPinnedNode(data);
         data.block = data.block == null ? block : dom(data.block, block);
-        assert isValid(data);
+        assert isValid(data) : data.node.uniqueName()+" at "+data.block.entry.uniqueName();
     }
 
     /**
@@ -328,8 +328,6 @@ public class Scheduler {
             for(int i=1; i<r.nIns(); i++) {
                 if (od(r.in(i)).map(d->d.block==null).orElse(false)) return false;
             }
-        } else if (node instanceof XCtrlNode) {
-            return false;
         } else {
             assert d(node.in(0)).block != null;
         }
@@ -405,7 +403,7 @@ public class Scheduler {
                 }
             }
             if (!(node instanceof ReturnNode))
-                for (Node n:node._outputs) if (n!=null && n.isCFG() && isCFGNodeReady(n) && d(n).block == null) queue.push(d(n));
+                for (Node n:node._outputs) if (n.isCFG() && isCFGNodeReady(n) && d(n).block == null) queue.push(d(n));
             var b = block;
             for(var in:data.node._inputs) od(in).ifPresent(d->update(d, b));
         }
@@ -451,7 +449,7 @@ public class Scheduler {
             node = data.node;
             assert node.isCFG();
             if (!(node instanceof ReturnNode)) {
-                for (var out : node._outputs) if (out!=null && out.isCFG() && isNotXCtrl(out)) markAlive(cfgQueue, out, true);
+                for (var out : node._outputs) if (out.isCFG() && isNotXCtrl(out)) markAlive(cfgQueue, out, true);
             }
             for (var in : node._inputs) if(in!=null && !in.isCFG() && isNotXCtrl(in)) markAlive(dataQueue, in, false);
         }
@@ -505,7 +503,7 @@ public class Scheduler {
      */
     private static Node findSingleCFGOut(Node node) {
         if (node instanceof StartNode) {
-            for(var n:node._outputs) if (n instanceof CProjNode p && p._idx==0) return p;
+            for(var n:node._outputs) if (n instanceof ProjNode p && p._idx==0) return p;
             return null;
         }
         assert node._outputs.stream().filter(Node::isCFG).limit(2).count()<=1;
@@ -572,7 +570,7 @@ public class Scheduler {
             switch(block.exit) {
                 case null: break;
                 case IfNode i:
-                    for(var out:i._outputs) if (out instanceof CProjNode p) block.next[p._idx] = blocks.get(p);
+                    for(var out:i._outputs) if (out instanceof ProjNode p) block.next[p._idx] = blocks.get(p);
                     break;
                 case RegionNode r:
                     block.next[0] = blocks.get(r);
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java b/chapter12/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
index b8437b50..14baadba 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
@@ -3,9 +3,7 @@ package com.seaofnodes.simple.fuzzer;
 import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.node.ScopeNode;
 
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.Random;
+import java.util.*;
 import java.util.function.Predicate;
 
 /**
@@ -70,11 +68,10 @@ public class ScriptGenerator {
 
     private static class TypeStruct extends Type {
         record Field (String name, Type type, TypeStruct struct) {}
-        final Field[] fields;
+        Field[] fields;
         final TypeNullable nullable = new TypeNullable(this);
-        TypeStruct(String name, Field[] fields) {
+        TypeStruct(String name) {
             super(name);
-            this.fields = fields;
         }
         boolean isa(Type other) { return this == other || other == nullable; }
     }
@@ -90,21 +87,7 @@ public class ScriptGenerator {
 
     }
 
-    private static final Type TYPE_FLT = new Type("flt");
-
-    private static class TypeInt extends Type {
-
-        TypeInt() {
-            super("int");
-        }
-
-        @Override
-        boolean isa(Type other) {
-            return super.isa(other) || other == TYPE_FLT;
-        }
-    }
-
-    private static final Type TYPE_INT = new TypeInt();
+    private static final Type TYPE_INT = new Type("int");
 
 
     private static class Variable {
@@ -159,6 +142,10 @@ public class ScriptGenerator {
      */
     private final ArrayList<TypeStruct> structs = new ArrayList<>();
     /**
+     * All forward declared structs
+     */
+    private final ArrayList<TypeStruct> forwardStructs = new ArrayList<>();
+    /**
      * Allow to declare structs.
      */
     private boolean allowStructs = true;
@@ -301,6 +288,7 @@ public class ScriptGenerator {
         for (var s:structs) {
             if (s.name.equals(name)) return s;
         }
+        for (var s:forwardStructs) if (s.name.equals(name)) return s;
         return null;
     }
 
@@ -333,12 +321,18 @@ public class ScriptGenerator {
         return v;
     }
 
+    private <T> T randFromList(List<T> list) {
+        return list.get(random.nextInt(list.size()));
+    }
+
     /**
      * Get a random structure name
      * @return A random structure name
      */
     private String getStructName() {
-        if (!structs.isEmpty() && generateInvalid()) return structs.get(random.nextInt(structs.size())).name;
+        if (!structs.isEmpty() && generateInvalid()) return randFromList(structs).name;
+        if (!forwardStructs.isEmpty() && generateInvalid()) return randFromList(forwardStructs).name;
+
         // Generate a new random struct name
         StringBuilder sb = getRandomName();
         var v = sb.toString();
@@ -357,16 +351,26 @@ public class ScriptGenerator {
      * Get a random type
      * @return A random type
      */
-    private Type getType() {
+    private Type getType(boolean allowForward) {
         int t = random.nextInt(10);
         if( t<5 || structs.isEmpty() ) return TYPE_INT;
-        if( t<7 ) return TYPE_FLT;
-        var idx = random.nextInt(structs.size());
-        TypeStruct struct = structs.get(idx);
+        if (allowForward && random.nextInt(10)==0) {
+            int i=random.nextInt(forwardStructs.size()+1);
+            if (i>0) return forwardStructs.get(i-1).nullable;
+            var name = getStructName();
+            var struct = new TypeStruct(name);
+            forwardStructs.add(struct);
+            return struct.nullable;
+        }
+        TypeStruct struct = randFromList(structs);
         if (random.nextBoolean()) return struct.nullable;
         return struct;
     }
 
+    private Type getType() {
+        return getType(false);
+    }
+
     /**
      * Generates a program and writes it into the string builder supplied in the constructor.
      * @return If the program is allowed to be invalid returns if something potentially invalid was generated.
@@ -426,19 +430,28 @@ public class ScriptGenerator {
      * @return 0
      */
     public int genStruct() {
-        var name = getStructName();
+        int idx = random.nextInt(forwardStructs.size()+10);
+        TypeStruct struct;
+        if (idx < 10) {
+            var name = getStructName();
+            struct = new TypeStruct(name);
+            forwardStructs.add(struct);
+        } else {
+            struct = forwardStructs.get(idx-10);
+        }
         var fields = new TypeStruct.Field[generateInvalid() ? 0 : random.nextInt(10)];
-        var struct = new TypeStruct(name, fields);
-        sb.append("struct ").append(name).append(" {\n");
+        sb.append("struct ").append(struct.name).append(" {\n");
         indentation += INDENTATION;
         for (int i=0; i<fields.length; i++) {
             var fieldName = getRandomName();
-            var type = getType();
+            var type = getType(true);
             printIndentation().append(type.name).append(" ").append(fieldName).append(";\n");
             fields[i] = new TypeStruct.Field(fieldName.toString(), type, struct);
         }
         indentation -= INDENTATION;
         printIndentation().append("}");
+        struct.fields = fields;
+        forwardStructs.remove(struct);
         structs.add(struct);
         return 0;
     }
@@ -697,7 +710,7 @@ public class ScriptGenerator {
      */
     public void genExpression(Type type, boolean change) {
         if (change && generateInvalid()) type = getType();
-        if (type != TYPE_INT && type != TYPE_FLT) {
+        if (type != TYPE_INT) {
             genUnary(type, false);
             return;
         }
@@ -714,7 +727,7 @@ public class ScriptGenerator {
      */
     public void genUnary(Type type, boolean change) {
         if (change && generateInvalid()) type = getType();
-        if (type != TYPE_INT && type != TYPE_FLT) {
+        if (type != TYPE_INT) {
             genSuffix(type, false);
             return;
         }
@@ -794,17 +807,16 @@ public class ScriptGenerator {
      */
     public void genConst(Type type) {
         if (generateInvalid()) type = getType();
-        if (type == TYPE_INT || (type == TYPE_FLT && random.nextBoolean())) {
+        if (type == TYPE_INT) {
             var rand = random.nextInt(10);
             switch (rand) {
                 case 0 -> sb.append("true");
                 case 1 -> sb.append("false");
                 default -> sb.append(random.nextInt(1<<(rand-2)));
             }
-        } else if (type == TYPE_FLT) {
-            sb.append(random.nextFloat());
+
         } else if (type instanceof TypeNullable n) {
-            if (random.nextBoolean()) {
+            if ((n.base instanceof TypeStruct s && s.fields == null) || random.nextBoolean()) {
                 sb.append("null");
             } else {
                 sb.append("new ").append(generateInvalid() ? getRandomName() : n.base.name);