[cvs-nhc98] patch applied (hat): Fix a small bug introduced when adding derived Read on named fields.

[Malcolm Wallace]

Thu Jun 15 09:41:05 PDT 2000  malcolm
  * Fix a small bug introduced when adding derived Read on named fields.
  A nullary constructor on a datatype was considered as having named fields,
  which of course did not match the derived Show instance.  Added an extra
  test for a nullary constructor, so it is treated normally.

    M ./src/compiler98/DeriveRead.hs -1 +1