I believe what you are thinking of is called "Haskell Prime". Haskell' is an effort to evolve the language standard of Haskell, and my impression of it has always been that it's rather analogous to Python 3, except that Haskell seems to evolve much more quickly than Python did, and in ways other than the accretion of new language builtins and keywords.

If you've not used Haskell in a decade, I think you'll find the language has changed significantly since then, but that sometimes the language disguises itself by choosing conservative language defaults that are maximally compatible. If you want to see how far Haskell has come it will require you to use a number of LANGUAGE pragmas to get the benefits of the most recent innovations.