Deprecated feature section
Fri, 26 Oct 2001 09:05:39 +0200 (MET DST)
George Russel proposed a search for things which should be deprecated.
I have a very distinct unfondness for contexts in algebraic data type
declarations. They make absolutely no difference except move type
errors to a different part of a program (or rather, they add type
errors). In that sense they could be said to be quite harmless, but
they dramatically complicate the typing rules for everything involving
algebraic data types, especially when combined with labelled fields.
Seconded! There is a sensible meaning for contexts on data-type declarations,
but Haskell ones don't have it. (See my paper "Restricted Data Types" in the
Haskell workshop a couple of years ago). At present they are simply useless.