testsuite: Assert that testsuite ways are known
[ghc.git] / testsuite / tests / typecheck / should_compile / tc114.hs
1 {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies,
2 FlexibleInstances #-}
3
4 -- !!! Functional dependencies
5 -- This broke an early impl of functional dependencies
6
7 module ShouldCompile where
8
9 class Foo r a | r -> a where
10 foo :: a -> r
11
12 instance Foo (Maybe e) e where
13 foo = Just
14
15 bad:: Num e => Maybe e
16 bad = foo 0