Hi, with 6.5.20060201 I get now an error for some overlapping instances that were ok for ghc-6.4.1. Did some options change? I use: -fglasgow-exts -fno-monomorphism-restriction \ -fallow-overlapping-instances -fallow-undecidable-instances Christian Common/ATerm/ConvInstances.hs:39:0: Overlapping instances for Typeable (Common.Lib.Graph.Gr a b) arising from the superclasses of an instance declaration at Common/ATerm/ConvInstances.hs:39:0 Matching instances: instance (Data.Typeable.Typeable1 s, Typeable a) => Typeable (s a) -- Imported from Data.Typeable instance [overlap ok] (Typeable a, Typeable b) => Typeable (Common.Lib.Graph.Gr a b) -- Defined at Common/ATerm/ConvInstances.hs:34:0 In the instance declaration for `ShATermConvertible (Common.Lib.Graph.Gr a b)'