Re: [Haskell-cafe] Why does this blow the stack?

On Fri, 2007-12-21 at 09:56 -0800, David Benbennick wrote:

On Dec 21, 2007 9:51 AM, Justin Bailey wrote:

...

I think its [1..] which is building up the unevaluated thunk. Using this definition of dropTest does not blow the stack:

It also works if you do [(1::Int) ..] !! n, but not with [(1::Integer) ..] !! n

Sounds like GHC is being smart about strictness for Ints, but doesn't know that Integer is equally strict. If that's right, it's a bug in GHC.

It is a bug in GHC. From http://darcs.haskell.org/packages/base/GHC/Enum.lhs enumFrom (I# x) = eftInt x maxInt# where I# maxInt# = maxInt -- Blarg: technically I guess enumFrom isn't strict! ... eftInt x y | x ># y = [] | otherwise = go x where go x = I# x : if x ==# y then [] else go (x +# 1#)