Fix RESTORE...?

SMILEBASIC/VM.d

@@ -1665,6 +1665,22 @@ class RestoreCode : Code
         return "restore " ~ label.to!string;
     }
 }
+class RestoreUndefinedLabelCode : Code
+{
+    wstring label;
+    this(wstring label)
+    {
+        this.label = label;
+    }
+    override void execute(VM vm)
+    {
+        throw new UndefinedLabel();
+    }
+    override string toString(VM vm)
+    {
+        return "restoreundeflabel " ~ label.to!string;
+    }
+}
 class RestoreExprCode : Code
 {
     DataTable datatable;

SMILEBASIC/compiler.d

@@ -1236,7 +1236,15 @@ class Compiler
             if(c.type == CodeType.RestoreCodeS)
             {
                 auto restore = cast(RestoreCodeS)c;
-                code[i] = new RestoreCode(s.data.label[restore.label], s.data);
+                auto label = s.data.label.get(restore.label, int.min);
+                if (label != int.min)
+                {
+                    code[i] = new RestoreUndefinedLabelCode(restore.label);
+                }
+                else
+                {
+                    code[i] = new RestoreCode(label, s.data);
+                }
             }
         }
         genCode(new EndVM());