diff options
author | Manuel M T Chakravarty <chak@cse.unsw.edu.au> | 2007-08-31 12:04:31 +0000 |
---|---|---|
committer | Manuel M T Chakravarty <chak@cse.unsw.edu.au> | 2007-08-31 12:04:31 +0000 |
commit | 1c2badd480a7facf25067f17afc395e3284027dd (patch) | |
tree | df857154f1df0a944b46ee3fe2fdbf0bb41f969c /testsuite/tests/ghc-regress/indexed-types/should_compile/ColGivenCheck.hs | |
parent | 186a2abe7b608dcb541165cda8ac594b13abf8e7 (diff) | |
download | haskell-1c2badd480a7facf25067f17afc395e3284027dd.tar.gz |
Tom Schrijvers' type family tests
Diffstat (limited to 'testsuite/tests/ghc-regress/indexed-types/should_compile/ColGivenCheck.hs')
-rw-r--r-- | testsuite/tests/ghc-regress/indexed-types/should_compile/ColGivenCheck.hs | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/testsuite/tests/ghc-regress/indexed-types/should_compile/ColGivenCheck.hs b/testsuite/tests/ghc-regress/indexed-types/should_compile/ColGivenCheck.hs new file mode 100644 index 0000000000..288c6e0608 --- /dev/null +++ b/testsuite/tests/ghc-regress/indexed-types/should_compile/ColGivenCheck.hs @@ -0,0 +1,20 @@ +{-# LANGUAGE TypeFamilies #-} + +module ColInference where + +type family Elem c + +type instance Elem [e] = e + +class Col c where + isEmpty :: c -> Bool + add :: c -> Elem c -> c + headTail :: c -> (Elem c,c) + +addAll :: (Col c1, Col c2, Elem c1 ~ Elem c2) => c1 -> c2 -> c2 +addAll c1 c2 + | isEmpty c1 + = c2 + | otherwise + = let (x,c1') = headTail c1 + in addAll c1' (add c2 x) |