diff options
| author | David Terei <davidterei@gmail.com> | 2011-07-20 11:09:03 -0700 |
|---|---|---|
| committer | David Terei <davidterei@gmail.com> | 2011-07-20 11:26:35 -0700 |
| commit | 16514f272fb42af6e9c7674a9bd6c9dce369231f (patch) | |
| tree | e4f332b45fe65e2a7a2451be5674f887b42bf199 /testsuite/tests/typecheck/should_fail/FailDueToGivenOverlapping.hs | |
| parent | ebd422aed41048476aa61dd4c520d43becd78682 (diff) | |
| download | haskell-16514f272fb42af6e9c7674a9bd6c9dce369231f.tar.gz | |
Move tests from tests/ghc-regress/* to just tests/*
Diffstat (limited to 'testsuite/tests/typecheck/should_fail/FailDueToGivenOverlapping.hs')
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/FailDueToGivenOverlapping.hs | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/testsuite/tests/typecheck/should_fail/FailDueToGivenOverlapping.hs b/testsuite/tests/typecheck/should_fail/FailDueToGivenOverlapping.hs new file mode 100644 index 0000000000..505eddcad1 --- /dev/null +++ b/testsuite/tests/typecheck/should_fail/FailDueToGivenOverlapping.hs @@ -0,0 +1,27 @@ +{-# LANGUAGE FlexibleContexts #-}
+
+module FailDueToGivenOverlapping where
+
+class C a where
+
+class D a where
+ dop :: a -> ()
+
+
+instance C a => D [a]
+
+-- should succeed since we can't learn anything more for 'a'
+foo :: (C a, D [Int]) => a -> ()
+foo x = dop [x]
+
+
+class E a where
+ eop :: a -> ()
+
+instance E [a] where
+ eop = undefined
+
+-- should fail since we can never be sure that we learnt
+-- everything about the free unification variable.
+bar :: E [Int] => () -> ()
+bar _ = eop [undefined]
|