For example I know 0 : 1 : [] gives [0, 1].

But shouldn't it produce a type fault in a consistent world?

Int:Int:List isn't properly a list.  It mixes types.

I expect something like:

Let GSN mean general_scalar_null.

1 : 2 : GSN  -- works

1 : 2 : []  -- type fault, cannot mix int and empty list in the same list.

And why does [] == [] : []

instead of [[], []] == [] : []

What sorts of nullity are there in core Haskell?

Trent.