It should not have worked before. Consider I# $ 3# ($) is a polymorphic function and takes two *pointer* arguments. If we actually called it with I# and 3# as arguments we might seg-fault when we call the GC when allocating the box. Polymorphic type variables (in this case in the type of ($)) can only be instantiated with boxed types. Simon | -----Original Message----- | From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell- | users-bounces@haskell.org] On Behalf Of Roel van Dijk | Sent: 09 February 2012 19:57 | To: glasgow-haskell-users@haskell.org | Subject: Kind error in GHC-7.4.1, works in GHC-7.2.2 | | Hello, | | I have some code that compiled fine in GHC-7.2.2 but fails in | GHC-7.4.1 with a kind error. | | | {-# LANGUAGE MagicHash, NoImplicitPrelude, PackageImports #-} | import "base" Data.Function ( ($) ) | import "base" GHC.Exts ( Int(I#) ) | import "base" Prelude ( Integral, fromIntegral, toInteger ) | import "integer-gmp" GHC.Integer.Logarithms ( integerLogBase# ) | | intLog :: (Integral a) => a -> a | intLog x = fromIntegral $ I# $ integerLogBase# 10 (toInteger x) | | | This results in the following error: | | Couldn't match kind `#' against `*' | In the second argument of `($)', namely | `I# $ integerLogBase# 10 (toInteger x)' | In the expression: | fromIntegral $ I# $ integerLogBase# 10 (toInteger x) | In an equation for `intLog': | intLog x = fromIntegral $ I# $ integerLogBase# 10 (toInteger x) | | | Simply eliminating some $'s using parenthesis solves the problem: | | intLog x = fromIntegral $ I# (integerLogBase# 10 (toInteger x)) | | Why do I get the above kind error? Could it be a bug in GHC? | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users