April 2002 - Hugs-Bugs

Hanging when loading standard prelude
by jason doty 03 Apr '02

03 Apr '02

Hugs December 2001 release SGI IRIX 6.5.14 gcc version 2.95.2 After compiling, hugs would hang when loading the standard prelude. The source of the bug seems to be line 516 of input.c. Changing "EOF" to "(char)-1" fixed it. hope this helps, jason doty

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Re: import/instance bug
by Sigbjorn Finne 03 Apr '02

03 Apr '02

Conal Elliott conal(a)microsoft.com writes: > > In Zeep.hs: > > module Zeep where > instance Eq [(Int, Int)] > > In tst.hs: > > import Zeep > import IOExts > > The result: .... > ERROR "c:\hugs98/lib\Array.hs":60 - Cannot justify constraints in > instance member binding > *** Expression : (==) > *** Type : Eq (Array a b) => Array a b -> Array a b ->Bool > *** Given context : Eq (Array a b) > *** Constraints : Eq [(a,b)] Not really a bug, see Jeff's response (&cure) to a very similar bug report: http://haskell.org/pipermail/hugs-bugs/2001-December/000545.html --sigbjorn

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import/instance bug
by Conal Elliott 02 Apr '02

02 Apr '02

In Zeep.hs: module Zeep where instance Eq [(Int, Int)] In tst.hs: import Zeep import IOExts The result: bash-2.05a$ hugs __ __ __ __ ____ ___ _________________________________________ || || || || || || ||__ Hugs 98: Based on the Haskell 98 standard ||___|| ||__|| ||__|| __|| Copyright (c) 1994-2001 ||---|| ___|| World Wide Web: http://haskell.org/hugs || || Report bugs to: hugs-bugs(a)haskell.org || || Version: December 2001 _________________________________________ Hugs mode: Restart with command line option +98 for Haskell 98 mode Reading file "c:\hugs98/lib\Prelude.hs": Type :? for help Prelude> :l Tst.hs Reading file "Tst.hs": Reading file "Zeep.hs": Reading file "c:\hugs98/lib/exts\IOExts.hs": Reading file "c:\hugs98/lib\IO.hs": Reading file "c:\hugs98/lib\Ix.hs": Reading file "c:\hugs98/lib\IO.hs": Reading file "c:\hugs98/lib\Array.hs": Reading file "c:\hugs98/lib\List.hs": Reading file "c:\hugs98/lib\Maybe.hs": Reading file "c:\hugs98/lib\List.hs": Reading file "c:\hugs98/lib\Array.hs": ERROR "c:\hugs98/lib\Array.hs":60 - Cannot justify constraints in instance member binding *** Expression : (==) *** Type : Eq (Array a b) => Array a b -> Array a b -> Bool *** Given context : Eq (Array a b) *** Constraints : Eq [(a,b)] My hugs settings are: +fe.qouiR -stgGlQwkIH -h5000000 -p"%s> " -r$$ -c40 - Conal

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