#1353: GHCi hangs when type checking
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Reporter: [EMAIL PROTECTED] | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: GHCi | Version: 6.6
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Os: Linux | Testcase:
Architecture: x86 |
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Comment (by [EMAIL PROTECTED]):
I've taken out the Mu. I then tried with a standard recursive data type
and that produced no joy. I then replaced that with an infinite list
(version attached).
GHC 6.6:
{{{
*Session> :t mkLoop (recvLog >~> returnS ())
mkLoop (recvLog >~> returnS ()) :: (Show t,
JustSendsRecvs (SessionSpec (Loop (SessionSpec s)))
(SessionSpec (Loop (SessionSpec ol)))
(SessionSpec (Loop (SessionSpec il))),
JustSendsRecvs (SessionSpec (RecvT t (Loop (SessionSpec s))))
(SessionSpec (Loop (SessionSpec ol)))
(SessionSpec (SessT t (Loop (SessionSpec il)))),
UnrollLoop (SessionSpec (Loop (SessionSpec il)))
(SessionSpec (SessT t (Loop (SessionSpec il)))),
UnrollLoop (SessionSpec (Loop (SessionSpec ol)))
(SessionSpec (Loop (SessionSpec ol))),
UnrollLoop (SessionSpec (Loop (SessionSpec s)))
(SessionSpec (RecvT t (Loop (SessionSpec s))))) =>
SessionState (SessionSpec (Loop (SessionSpec s)))
(Loop (SessionSpec ol))
(Loop (SessionSpec il))
-> IO ((), SessionState (SessionSpec EndT) EndT EndT)
}}}
ghc 20070514:
{{{
*Session> :t mkLoop (recvLog >~> returnS ())
mkLoop (recvLog >~> returnS ()) :: (ReplaceLoopEnd
(SessionSpec il)
(SessionSpec (Loop (SessionSpec
il)))
(SessionSpec (SessT t (Loop
(SessionSpec il)))),
ReplaceLoopEnd
(SessionSpec ol)
(SessionSpec (Loop (SessionSpec
ol)))
(SessionSpec [SessionSpec ol]),
ReplaceLoopEnd
(SessionSpec s)
(SessionSpec (Loop (SessionSpec s)))
(SessionSpec (RecvT t (Loop
(SessionSpec s)))),
Show t,
JustSendsRecvs (SessionSpec s)
(SessionSpec ol) (SessionSpec il)) =>
SessionState
(SessionSpec (Loop (SessionSpec s)))
(Loop (SessionSpec ol))
(Loop (SessionSpec il))
-> IO ((), SessionState (SessionSpec
EndT) EndT EndT)
}}}
so the new one is expanding the UnrollLoop into ReplaceLoopEnd... but now,
ghc 6.6:
{{{
*Session> :t Proc $ mkLoop (recvLog >~> returnS ())
Proc $ mkLoop (recvLog >~> returnS ()) :: (ZeroOrMoreSteps (SessionSpec
(Loop (SessionSpec s)))
(SessionSpec EndT),
Show t,
JustSendsRecvs (SessionSpec (Loop (SessionSpec s)))
(SessionSpec (Loop (SessionSpec ol)))
(SessionSpec (Loop (SessionSpec il))),
JustSendsRecvs (SessionSpec (RecvT t (Loop (SessionSpec s))))
(SessionSpec (Loop (SessionSpec ol)))
(SessionSpec (SessT t (Loop (SessionSpec il)))),
UnrollLoop (SessionSpec (Loop (SessionSpec il)))
(SessionSpec (SessT t (Loop (SessionSpec il)))),
UnrollLoop (SessionSpec (Loop (SessionSpec ol)))
(SessionSpec (Loop (SessionSpec ol))),
UnrollLoop (SessionSpec (Loop (SessionSpec s)))
(SessionSpec (RecvT t (Loop (SessionSpec s))))) =>
Proc (SessionSpec (Loop (SessionSpec s)))
(SessionSpec EndT)
(Loop (SessionSpec ol))
EndT
(Loop (SessionSpec il))
EndT
}}}
but ghc 20070514:
{{{
*Session> :t Proc $ mkLoop (recvLog >~> returnS ())
...hang...
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1353>
GHC <http://www.haskell.org/ghc/>
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