What steps will reproduce the problem?

A Haskell module (Geometry.hs) contains a data definition ending on line 7 with

deriving (..., Ix)

When this module imports Ix, it does not compile with the following

Compiling Geometry ( ...../Geometry.hs ) yhc: -- during when renaming Error: Identifier Data.Ix._tupleRange used at 7:35-7:36 is not defined. Error: Identifier Data.Ix.inRange used at 7:35-7:36 is not defined. Error: Identifier Data.Ix.range used at 7:35-7:36 is not defined. Error: Type class Data.Ix.Ix used at 7:35-7:36 is not defined. Error: Identifier Data.Ix._tupleIndex used at 7:35-7:36 is not defined. Error: Identifier Data.Ix.index used at 7:35-7:36 is not defined.

If "import Ix" is replaced with "import Data.Ix" everything compiles fine.

The "Data.Ix" module defines class Ix, but the "Ix" module (haskell98) only imports Data.Ix and re-exports class methods it defines.