1.1 --- a/src/HOL/Imperative_HOL/Heap.thy	Fri Aug 13 14:41:27 2010 +0200
     1.2 +++ b/src/HOL/Imperative_HOL/Heap.thy	Fri Aug 13 14:43:16 2010 +0200
     1.3 @@ -14,6 +14,10 @@
     1.4  
     1.5  class heap = typerep + countable
     1.6  
     1.7 +instance unit :: heap ..
     1.8 +
     1.9 +instance bool :: heap ..
    1.10 +
    1.11  instance nat :: heap ..
    1.12  
    1.13  instance prod :: (heap, heap) heap ..