Fix impredicativity (again)
[ghc.git] / testsuite / tests / typecheck / should_fail / tcfail109.hs
1 {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies #-}
2
3 -- Strangely, this program does not elicit an error message
4 -- in GHC 5.03. I don't know why. It fails correctly in
5 -- 5.04
6
7
8 module ShouldFail where
9
10 class Eq ce => Collects e ce | ce -> e where
11 empty :: ce
12 empty = error("empty")
13
14 data Stupid = Stupid -- without equality
15
16 instance Collects Bool Stupid where