#5372: DisambiguateRecordFields with qualified import can cause panic
---------------------------------+------------------------------------------
Reporter: shelarcy | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.3 | Keywords:
Testcase: | Blockedby:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: Compile-time crash
---------------------------------+------------------------------------------
When I'm using DisambiguateRecordFields with GHC 7.2.1 RC1
(7.2.0.20110728), I encounter panic.
{{{
module M where
data S = MkS { x :: Int, y :: Bool }
}}}
{{{
{-# LANGUAGE DisambiguateRecordFields #-}
module Foo where
import qualified M
notScope (MkS { x = n }) = n
}}}
This code causes panic when using GHC 7.2.1 RC1, and GHC 7.3.20110802.
{{{
(snip)
[1 of 2] Compiling M ( M.hs, interpreted )
[2 of 2] Compiling Foo ( Test.hs, interpreted )
ghc.exe: panic! (the 'impossible' happened)
(GHC version 7.3.20110802 for i386-unknown-mingw32):
find_tycon
MkS{d 02A}
[]
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
>
}}}
This problem is caused by using DisambiguateRecordFields extention. When I
remove DisambiguateRecordFields extention from Foo module, GHC doesn't
cause panic.
{{{
module Foo where
import qualified M
notScope (MkS { x = n }) = n
}}}
{{{
> :r
[2 of 2] Compiling Foo ( Test.hs, interpreted )
Test.hs:4:11:
Not in scope: data constructor `MkS'
Perhaps you meant `M.MkS' (imported from M)
Test.hs:4:17: `x' is not a (visible) field of constructor `MkS'
Failed, modules loaded: M.
*M>
}}}
GHC 7.0.4 doesn't cause panic even though using DisambiguateRecordFields
extention.
{{{
[1 of 2] Compiling M ( M.hs, interpreted )
[2 of 2] Compiling Foo ( Test.hs, interpreted )
Test.hs:4:11: Not in scope: data constructor `MkS'
Test.hs:4:17: `x' is not a (visible) field of constructor `MkS'
Failed, modules loaded: M.
}}}
So, I think this problem comes from
5d89565b043eaff9028205b79363ef0d0c17ff17 .
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5372>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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