module TypeClassError where 

f0 xs = map +1 xs
f1 xs = map (-1) xs
f2 n = [n] : [4,5,6]
f3 r = r * sin .2

-- 出典: Bastiaan Heeren and Jurriaan Hage: ``Type Class Directives'' (スライド)
-- http://people.cs.uu.nl/bastiaan/padl05-heeren-slides.pdf