[ihm]

I intended the phrase "core" to refer to aspects of the language which are commonly used, leaving aside less frequently used or more obscure GHC extensions like existential quantification, functional dependencies, implicit params, etc, etc.

Which language features that I mentioned do you not think are commonly used in Haskell?

[mej10]

Backpack, for example, was _literally_ only released in the latest version of GHC. Do you just glance over the subreddit occasionally or something? That would explain your list.

You list things that aren't part of the Haskell standard and just claim that they are "core" while not even listing all of the _actually core_ features of OCaml -- all of its OO parts.