On 11-10-16 01:56 PM, Patrick Browne wrote:

I get the same results from Listing 1 and Listing 2 below.

I carefully diff'ed the two listings and found no difference except for comments.

-- ====Listing 1- Subclass==== data Shed = Shed

class Building building where addressB :: building -> Integer addressB b = 1

-- subclass, but none in Listing 2 class Building house => House house where addressH :: house -> Integer addressH b = 0

instance Building Shed where instance House Shed where

-- ====Listing 2 -- No subclass==== data Shed = Shed

class Building building where addressB :: building -> Integer addressB b = 1

-- No subclass class Building house => House house where addressH :: house -> Integer addressH b = 0

instance Building Shed where instance House Shed where