Hi
sq = squishiness $ Table {colour = Black, weight=1, height= 2} main = putStr $ show sq
squishiness is just translated to: squishiness :: Furniture -> Double squishiness (Chair _ _ x) = x squishiness _ = error "doh"
main: No match in record selector Main.squishiness
Hence this is a pattern match error (runtime), not a type error (compile time). There are people working on extending the types to catch this kind of thing, and also people working on static checkers to catch patter match errors [1] and people working on annotations to get this kind of thing [2]. It's not a solved problem yet, but certainly I have a demo checker that would have spotted this easily. Thanks Neil [1] http://www-users.cs.york.ac.uk/~ndm/projects/catch.php [2] http://www.cl.cam.ac.uk/~nx200/research/escH-hw.ps