Re: GHC 7.0.4 recursion while trying to derive type
Am 08.01.2012 04:39, schrieb Bogdan Opanchuk:
Hello,
Consider the following code:
{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances, OverlappingInstances,
UndecidableInstances, FunctionalDependencies #-}
We have also such (cruel) code using these extension.
t4.hs:17:31:
Context reduction stack overflow; size = 21
Use -fcontext-stack=N to increase stack size to N
Our code compiles with ghc-7-0.4 if we add -fcontext-stack=31 to the ghc
command line.
Does your code compile with an increased (try 100) context-stack?
[..]
So, the question is, could anyone please tell me, is what I am trying
to do actually correct, and what was changed from 7.0.4 to 7.2.2 to
make it work?
I cannot answer this, but our code also compiles with ghc-7.2.2 using a
lower context-stack (of 26).
HTH Christian
Thank you in advance.
Best regards,
Bogdan
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Re: GHC 7.0.4 recursion while trying to derive type
Am 09.01.2012 13:16, schrieb Christian Maeder: I cannot answer this, but our code also compiles with ghc-7.2.2 using a lower context-stack (of 26). Apologies, I've just re-checked and noticed that our code changed and needs consistently -fcontext-stack=26 for ghc-7.2.2 and ghc-7.0.4 (and ghc-7.0.2). C. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.0.4 recursion while trying to derive type
Hello Christian, On Mon, Jan 9, 2012 at 11:31 PM, Christian Maeder christian.mae...@dfki.de wrote: We have also such (cruel) code using these extension. I understand that this code is not very good; I am just learning Haskell, and it is an experiment to see what its type system can handle. I cannot answer this, but our code also compiles with ghc-7.2.2 using a lower context-stack (of 26). Apologies, I've just re-checked and noticed that our code changed and needs consistently -fcontext-stack=26 for ghc-7.2.2 and ghc-7.0.4 (and ghc-7.0.2). I just tried compiling my code with ghc7.0.4 and stack size 100, and it produces the same error. In fact, I would be surprised if it helped, because I would expect either infinite recursion (when type derivation fails) or successful compilation with some small stack size (definitely less than 26). The latter is the case for ghc7.2.2, which successfully compiles my code with stack size 3. Best regards, Bogdan ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
RE: GHC 7.0.4 recursion while trying to derive type
If you think there's a bug here, could you open a ticket a repro case, please? Many thanks Simon | -Original Message- | From: glasgow-haskell-users-boun...@haskell.org [mailto:glasgow-haskell- | users-boun...@haskell.org] On Behalf Of Bogdan Opanchuk | Sent: 09 January 2012 13:00 | To: Christian Maeder | Cc: glasgow-haskell-users@haskell.org | Subject: Re: GHC 7.0.4 recursion while trying to derive type | | Hello Christian, | | On Mon, Jan 9, 2012 at 11:31 PM, Christian Maeder | christian.mae...@dfki.de wrote: | We have also such (cruel) code using these extension. | | I understand that this code is not very good; I am just learning | Haskell, and it is an experiment to see what its type system can | handle. | | I cannot answer this, but our code also compiles with ghc-7.2.2 using a | lower context-stack (of 26). | Apologies, I've just re-checked and noticed that our code changed and needs | consistently -fcontext-stack=26 for ghc-7.2.2 and ghc-7.0.4 (and ghc- | 7.0.2). | | I just tried compiling my code with ghc7.0.4 and stack size 100, and | it produces the same error. In fact, I would be surprised if it | helped, because I would expect either infinite recursion (when type | derivation fails) or successful compilation with some small stack size | (definitely less than 26). The latter is the case for ghc7.2.2, which | successfully compiles my code with stack size 3. | | Best regards, | Bogdan | | ___ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.0.4 recursion while trying to derive type
Hello Simon, On Tue, Jan 10, 2012 at 12:17 AM, Simon Peyton-Jones simo...@microsoft.com wrote: If you think there's a bug here, could you open a ticket a repro case, please? Sure, I just did not think it was sensible to file a bug on something that had been apparently fixed in the most recent stable version of GHC. Here's the bug: http://hackage.haskell.org/trac/ghc/ticket/5759 Best regards, Bogdan ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
