diff options
Diffstat (limited to 'testsuite/tests/deriving/should_fail/T5287.hs')
| -rw-r--r-- | testsuite/tests/deriving/should_fail/T5287.hs | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/testsuite/tests/deriving/should_fail/T5287.hs b/testsuite/tests/deriving/should_fail/T5287.hs new file mode 100644 index 0000000000..6495b62be9 --- /dev/null +++ b/testsuite/tests/deriving/should_fail/T5287.hs @@ -0,0 +1,14 @@ +{-# LANGUAGE MultiParamTypeClasses, UndecidableInstances #-} +module Bug where +class A a oops +data D d = D d + +instance A a oops => Read (D a) +-- Actually this instance is ambiguous +-- and is now rightly rejected + +data E e = E (D e) deriving Read + +instance A Int Bool + + |