Hello, Can someone elucidate to me this behaviour from ghci 6.6.1? Why is the type of sqlist specialised to Integer? Prelude> let sq x = x * x Prelude> :t sq sq :: (Num a) => a -> a Prelude> sq 2.5 6.25 Prelude> :t map sq map sq :: (Num a) => [a] -> [a] Prelude> map sq [2.5] [6.25] This is all as I would expect so far, but: Prelude> let sqlist = map sq Prelude> :t sqlist sqlist :: [Integer] -> [Integer] And indeed, I get Prelude> sqlist [2.5] <interactive>:1:8: No instance for (Fractional Integer) ... etc Thanks! David -- The Wellcome Trust Sanger Institute is operated by Genome Research Limited, a charity registered in England with number 1021457 and a company registered in England with number 2742969, whose registered office is 215 Euston Road, London, NW1 2BE.