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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2012-05-14 13:54:06 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2012-05-14 13:54:06 +0100 |
| commit | d93dc415916f23088c70eb6613d685911fb14e23 (patch) | |
| tree | 869f71db60682987ea8389ff4258cf98ec60f056 /testsuite/tests/polykinds/T6015.hs | |
| parent | 6729fa6b2be246eca5a903f5311fc5456b20cb5a (diff) | |
| download | haskell-d93dc415916f23088c70eb6613d685911fb14e23.tar.gz | |
Test Trac #6015
Diffstat (limited to 'testsuite/tests/polykinds/T6015.hs')
| -rw-r--r-- | testsuite/tests/polykinds/T6015.hs | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/testsuite/tests/polykinds/T6015.hs b/testsuite/tests/polykinds/T6015.hs new file mode 100644 index 0000000000..8f91025f6d --- /dev/null +++ b/testsuite/tests/polykinds/T6015.hs @@ -0,0 +1,15 @@ +{-# LANGUAGE DataKinds, MultiParamTypeClasses, FunctionalDependencies, + PolyKinds, UndecidableInstances, ScopedTypeVariables #-} + +module T6015 where + +data Proxy a = Proxy + +class Value a t | a -> t where value :: Proxy a -> t + +instance Value True Bool where value _ = True + +instance Value a t => Value (Just a) (Maybe t) + where value _ = Just (value (Proxy :: Proxy a)) + +test = value (Proxy :: Proxy (Just True)) |