while1 grammar rule cleanup

Closes #172

test/simple_source/looping/04_while1_while1.py

@@ -19,10 +19,15 @@ while 1:
 while 1:
     if __name__:
         while 1:
-            if y:
+            if __name__:
                 break
             raise RuntimeError
     elif __file__:
         x = 2
     else:
         raise RuntimeError
+
+# Degenerate case. Note: we can't run becase this causes an infinite loop.
+# Suggested in issue #172
+while 1:
+    pass