Wow, that's ... interesting. Could this have to do with the way the
constraints are written? Has there been some change in
UndecidableInstances? I'll try simplifying the Eq, Ord, Show, etc.
constraints manually and see if that fixes it.
On Thu, Dec 1, 2022, 7:14 PM Li-yao Xia
GHC 9.4.3 with -O2 is miscompiling the derived Show and Eq instances for SeqT in logict-sequence.
main :: IO () main = print (pure 0 :: Seq Int) -- -O0, -O1: prints the Seq -- -O2: <<loop>>
On top of that, both hedgehog and hspec fail to catch `<<loop>>`.
main :: IO () main = defaultMain [ check $ property $ do let x = x :: Int -- obvious loop compiles to a thrown exception <<loop>> if x == x then pure () else pure () ] -- "thread blocked indefinitely in an STM transaction" -- meaning some thread is not getting cleaned up properly
main :: IO () main = hspec $ do describe "work" $ do it "works" $ do let x = x :: Int -- obvious loop compiles to a thrown exception <<loop>> if x == x then pure () else pure () :: IO () --- hangs
Cheers, Li-yao
On 2022-11-30 10:33 PM, David Feuer wrote:
The logict-sequence test suite consistently freezes up on the last test when compiled with GHC 9.4.3. logict-sequence and its test suite don't do anything special with that GHC/base version as far as I can see, or anything particularly strange in general, so I'm pretty confident the problem lies elsewhere. My best guesses are hedgehog, tasty, and tasty-hedgehog. Has anyone else run into weird issues with any/all of these on GHC 9.4.3?
David _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to:http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.