#5439: Crash in TcEnv.lhs line 461
---------------------------------+------------------------------------------
Reporter: mikhail.vorozhtsov | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 7.3
Resolution: | Keywords:
Testcase: | Blockedby:
Difficulty: | Os: Unknown/Multiple
Blocking: | Architecture: Unknown/Multiple
Failure: Compile-time crash |
---------------------------------+------------------------------------------
Changes (by mikhail.vorozhtsov):
* status: closed => new
* resolution: fixed =>
Comment:
I'm still getting the panic on my file.
{{{
$ git log -n 3 --format=oneline
fa71e6c795489ec267e0d048395c2c52bea6a164 Fix #4988: we were wrongly
running exception h...
c27df60d69ad54a69723510c57e238f31a59c532 Two small further extensions to
associated typ...
eb46e0de6eab60483f38ed2088d9de13d8e74e2f Fix the trimming of bind_fvs
(fixes Trac #5439...
$ ./validate --slow
...
$ grep panic testlog
$ ./inplace/bin/ghc-stage1 -c -fforce-recomp ~/Bug.hs
/home/mikhail_vorozhtsov/Bug.hs:83:39:
Couldn't match expected type `Peano n0'
with actual type `Attempt α0'
In the return type of a call of `Failure'
In the second argument of `($)', namely
`Failure (e :: SomeException)'
In the second argument of `($)', namely
`inj $ Failure (e :: SomeException)'
}}}
So far so good (the type error is expected), but then:
{{{
./inplace/bin/ghc-stage2 -c -fforce-recomp ~/Bug.hs
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 7.3.20110901 for x86_64-unknown-linux):
ASSERT failed! file compiler/typecheck/TcEnv.lhs line 461
register{v amR} [lid]
forall n{tv amS} [tv].
main:Main.HDropClass{tc r1d} n{tv amS} [tv] rs{tv amO} [ssk] =>
ghc-prim:GHC.Types.Bool{(w) tc 3c}
-> main:Main.Peano{tc rx} n{tv amS} [tv]
-> main:Main.WaitOps{tc rr}
(main:Main.HDrop{tc r1c} n{tv amS} [tv] rs{tv amO} [ssk])
-> ghc-prim:GHC.Types.IO{tc 32I} ghc-prim:GHC.Types.Bool{(w) tc 3c}
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
}}}
If I fix the type error reported by the stage1 compiler (by replacing "$
inj $" with "$ inj n $"), the panic goes away. The bootstrap compiler is
GHC 7.0.3.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5439#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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