More robust on broken inputs

2 files changed, 13 insertions, 1 deletions

diff --git a/chapter25/src/test/java/com/seaofnodes/simple/Chapter25Test.java b/chapter25/src/test/java/com/seaofnodes/simple/Chapter25Test.java
index a5ef67e8..f5e3d752 100644
--- a/chapter25/src/test/java/com/seaofnodes/simple/Chapter25Test.java
+++ b/chapter25/src/test/java/com/seaofnodes/simple/Chapter25Test.java
@@ -72,6 +72,17 @@ public class Chapter25Test {
         assertEquals("1",Eval2.eval(code,0));
     }
 
+    @Test
+    public void testFuzzerUnresolvedNumericLoop() {
+        CodeGen code = new CodeGen("""
+            arg=0;
+            while(arg+0)
+                while(-arg)
+                    arg=0;
+            """).driver(CodeGen.Phase.TypeCheck);
+        assertEquals("return 0;",code.print());
+    }
+
     @Test @Ignore
     public void testModule0() throws IOException {
         String MODDIR = "src/test/java/com/seaofnodes/simple/test0";
diff --git a/chapter25/src/test/java/com/seaofnodes/simple/Eval2.java b/chapter25/src/test/java/com/seaofnodes/simple/Eval2.java
index 715c499e..ea4ec326 100644
--- a/chapter25/src/test/java/com/seaofnodes/simple/Eval2.java
+++ b/chapter25/src/test/java/com/seaofnodes/simple/Eval2.java
@@ -148,7 +148,7 @@ public abstract class Eval2 {
         // Evaluate until exit or timeout.  Each outer loop step computes
         // all data nodes under some new Control.
         while( true ) {
-            assert BB!=null;
+            if( BB==null ) return null;
             traceCtrl(BB,trace);
             if( trace!=null ) System.out.println(F.p());
 
@@ -177,6 +177,7 @@ public abstract class Eval2 {
             case RegionNode r   :  break;
             default:               throw Utils.TODO();
             }
+            if( BB==null ) return null;
             assert !BB.isDead();
         }
     }