Panic "StgCmmEnv: variable not found" when building dhall with -O2
When building dhall's Dhall module with -O2, ghc panics:
Panic message
[34 of 40] Compiling Dhall ( src/Dhall.hs, /home/simon/src/dhall-haskell/dist-newstyle/build/x86_64-linux/ghc-8.8.2/dhall-1.29.0/opt/build/Dhall.o )
src/Dhall.hs:134:1: warning: [-Wunused-imports]
The import of ‘Data.Monoid’ is redundant
except perhaps to import instances from ‘Data.Monoid’
To import instances alone, use: import Data.Monoid()
|
134 | import Data.Monoid ((<>))
| ^^^^^^^^^^^^^^^^^^^^^^^^^
ghc: panic! (the 'impossible' happened)
(GHC version 8.8.2 for x86_64-unknown-linux):
StgCmmEnv: variable not found
lvl_s1ihUy
local binds for:
$l$wrealloc_g1ispG
$lrealloc_g1ispH
$lrealloc1_g1ispI
$l$wrealloc_g1ispJ
$lrealloc_g1ispK
$lrealloc1_g1ispL
$l$wrealloc_g1ispM
$lrealloc_g1ispN
$lrealloc1_g1ispO
$l$wrealloc_g1ispP
$lrealloc_g1ispQ
$lrealloc1_g1ispR
$l$wrealloc_g1ispS
$lrealloc_g1ispT
$lrealloc1_g1ispU
$l$wrealloc_g1ispV
$lrealloc_g1ispW
$lrealloc1_g1ispX
$l$wrealloc_g1ispY
$lrealloc_g1ispZ
$lrealloc1_g1isq0
$l$wrealloc_g1isq1
$lrealloc_g1isq2
$lrealloc1_g1isq3
$l$wrealloc_g1isq4
$lrealloc_g1isq5
$lrealloc1_g1isq6
$l$wrealloc_g1isq7
$lrealloc_g1isq8
$lrealloc1_g1isq9
$l$wrealloc_g1isqa
$lrealloc_g1isqb
$lrealloc1_g1isqc
$l$wrealloc_g1isqd
$lrealloc_g1isqe
$lrealloc1_g1isqf
$l$wrealloc_g1isqg
$lrealloc_g1isqh
$lrealloc1_g1isqi
$lgo_g1isqj
genericToDhallWith
injectWith
genericAutoWith
autoWith
evaluateSettings
$fFromDhall(,)_$s$fSelectorMetaMetaSel
map1
map_foldrTree
$w$sgo13
void_$sgo13
void3
$fGenericFromDhallkU5
$fGenericFromDhallkU6
$fGenericFromDhallkU7
$fGenericFromDhallkU8
$fGenericFromDhallkU1_go
$fGenericFromDhallkU9
$s$fExceptionDetailedTypeError_$s$fShowDetailedTypeError
$s$fShowDetailedTypeError_$cshowsPrec
$w$sgo3
$wgo3
setIgnoringDuplicates1
$wouter1_r1ioPd
$wouter2_r1ioPe
$wouter3_r1ioPf
$wouter4_r1ioPg
lvl3_r1ioPh
lvl4_r1ioPi
lvl5_r1ioPj
lvl6_r1ioPk
lvl9_r1ioPn
lvl10_r1ioPo
$wouter5_r1ioPp
$wouter6_r1ioPq
$wouter7_r1ioPr
$wouter8_r1ioPs
$wouter9_r1ioPt
$wouter10_r1ioPu
$wouter11_r1ioPv
$wouter12_r1ioPw
lvl11_r1ioPy
$wouter13_r1ioPz
$spoly_$wfoldlM_loop_r1ioPA
$spoly_$wfoldlM_loop1_r1ioPB
$spoly_$wfoldlM_loop2_r1ioPC
$spoly_$wfoldlM_loop3_r1ioPD
lvl12_r1ioPE
$s$wtraverseTree_r1ioPF
$wtraverseTree_r1ioPG
sc_s1ipiB
sc1_s1ipiC
sc2_s1ipiD
sc3_s1ipiE
wild1_s1ipiF
dt1_s1ipiI
pr_s1ipiJ
m_s1ipiK
sf_s1ipiL
sat_s1iplc
sat_s1ipm2
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/utils/Outputable.hs:1159:37 in ghc:Outputable
pprPanic, called at compiler/codeGen/StgCmmEnv.hs:149:9 in ghc:StgCmmEnvWith -dcore-lint, ghc reports
Core lint message
*** Core Lint errors : in result of Simplifier ***
<no location info>: warning:
In the expression: lvl_sZFi
@ (Digit (Node (Elem b_XLt1)))
@ (FingerTree (Node (Elem b_XLt1)))
(let {
b1_aLq2 [OS=OneShot]
:: Validation
(ExtractErrors Src Void) (FingerTree (Node (Node (Elem b_XLt1))))
[LclId,
Unf=Unf{Src=<vanilla>, TopLvl=False, Value=False, ConLike=False,
WorkFree=False, Expandable=False, Guidance=IF_ARGS [] 540 0}]
b1_aLq2
= $wtraverseTree_sWdp
@ (Validation (ExtractErrors Src Void))
@ (Node (Elem a_XLsZ))
@ (Node (Elem b_XLt1))
sc_s121b
sc_s121c
lvl_sZFi
lvl_sZFj
(\ (t_iLut :: Node (Node (Elem a_XLsZ))) ->
case t_iLut of {
Node2 dt2_iLuH a2_iLuI b2_iLuJ ->
case sc_s121d a2_iLuI of {
Failure e1_aLob ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Node (Elem b_XLt1)))
(case sc_s121d b2_iLuJ of {
Failure e2_aLq9 ->
($fSemigroupNonEmpty_$c<>
@ (ExtractError Src Void)
(e1_aLob
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty
(ExtractError Src Void)))
(e2_aLq9
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty
(ExtractError Src Void))))
`cast` (Sym (N:ExtractErrors[0]
<Src>_R <Void>_R)
:: NonEmpty (ExtractError Src Void)
~R# ExtractErrors Src Void);
Success ds1_aLqc -> e1_aLob
});
Success a1_aLoe ->
case sc_s121d b2_iLuJ of {
Failure e1_aLqj ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Node (Elem b_XLt1)))
e1_aLqj;
Success x_aLqm ->
Success
@ (ExtractErrors Src Void)
@ (Node (Node (Elem b_XLt1)))
(Node2
@ (Node (Elem b_XLt1))
dt2_iLuH
a1_aLoe
x_aLqm)
}
};
Node3 dt2_iLuM a2_iLuN b2_iLuO c_iLuP ->
lvl_sZFi
@ (Node (Elem b_XLt1))
@ (Node (Node (Elem b_XLt1)))
(case sc_s121d a2_iLuN of {
Failure e1_aLob ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1)
-> Node (Node (Elem b_XLt1)))
(case sc_s121d b2_iLuO of {
Failure e2_aLq9 ->
($fSemigroupNonEmpty_$c<>
@ (ExtractError Src Void)
(e1_aLob
`cast` (N:ExtractErrors[0]
<Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty
(ExtractError
Src Void)))
(e2_aLq9
`cast` (N:ExtractErrors[0]
<Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty
(ExtractError
Src Void))))
`cast` (Sym (N:ExtractErrors[0]
<Src>_R <Void>_R)
:: NonEmpty (ExtractError Src Void)
~R# ExtractErrors Src Void);
Success ds1_aLqc -> e1_aLob
});
Success a1_aLoe ->
case sc_s121d b2_iLuO of {
Failure e1_aLqj ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1)
-> Node (Node (Elem b_XLt1)))
e1_aLqj;
Success x_aLqm ->
Success
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1)
-> Node (Node (Elem b_XLt1)))
(\ (dt_iLuE :: Node (Elem b_XLt1)) ->
Node3
@ (Node (Elem b_XLt1))
dt2_iLuM
a1_aLoe
x_aLqm
dt_iLuE)
}
})
(sc_s121d c_iLuP)
})
m_iLu7 } in
join {
$j_s13uy
:: ExtractErrors Src Void
-> Validation
(ExtractErrors Src Void)
(Digit (Node (Elem b_XLt1))
-> FingerTree (Node (Elem b_XLt1)))
[LclId[JoinId(1)], Arity=1]
$j_s13uy (e1_aLob [OS=OneShot] :: ExtractErrors Src Void)
= Failure
@ (ExtractErrors Src Void)
@ (Digit (Node (Elem b_XLt1)) -> FingerTree (Node (Elem b_XLt1)))
(case b1_aLq2 of {
Failure e2_aLq9 ->
($fSemigroupNonEmpty_$c<>
@ (ExtractError Src Void)
(e1_aLob
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty (ExtractError Src Void)))
(e2_aLq9
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty (ExtractError Src Void))))
`cast` (Sym (N:ExtractErrors[0] <Src>_R <Void>_R)
:: NonEmpty (ExtractError Src Void)
~R# ExtractErrors Src Void);
Success ds1_aLqc -> e1_aLob
}) } in
join {
$j_s13uz
:: Digit (Node (Elem b_XLt1))
-> Validation
(ExtractErrors Src Void)
(Digit (Node (Elem b_XLt1))
-> FingerTree (Node (Elem b_XLt1)))
[LclId[JoinId(1)], Arity=1]
$j_s13uz (a1_aLoe [OS=OneShot] :: Digit (Node (Elem b_XLt1)))
= case b1_aLq2 of {
Failure e1_aLqj ->
Failure
@ (ExtractErrors Src Void)
@ (Digit (Node (Elem b_XLt1))
-> FingerTree (Node (Elem b_XLt1)))
e1_aLqj;
Success x_aLqm ->
Success
@ (ExtractErrors Src Void)
@ (Digit (Node (Elem b_XLt1))
-> FingerTree (Node (Elem b_XLt1)))
(\ (dt_iL62 :: Digit (Node (Elem b_XLt1))) ->
case a1_aLoe of dt_XL68 { __DEFAULT ->
case dt_iL62 of dt_XL6b { __DEFAULT ->
Deep @ (Node (Elem b_XLt1)) dt1_iLu5 dt_XL68 x_aLqm dt_XL6b
}
})
} } in
case pr_iLu6 of {
One a2_iLuc ->
case fmap
@ (Validation (ExtractErrors Src Void))
sc_s121b
@ (Node (Elem b_XLt1))
@ (Digit (Node (Elem b_XLt1)))
(One @ (Node (Elem b_XLt1)))
(sc_s121d a2_iLuc)
of {
Failure e1_aLob -> jump $j_s13uy e1_aLob;
Success a1_aLoe -> jump $j_s13uz a1_aLoe
};
Two a2_iLuf b2_iLug ->
case sc_s121d a2_iLuf of {
Failure e1_aLob ->
let {
e1_XLFQ :: ExtractErrors Src Void
[LclId,
Unf=Unf{Src=<vanilla>, TopLvl=False, Value=False,
ConLike=False, WorkFree=False, Expandable=False,
Guidance=IF_ARGS [] 70 0}]
e1_XLFQ
= case sc_s121d b2_iLug of {
Failure e2_aLq9 ->
($fSemigroupNonEmpty_$c<>
@ (ExtractError Src Void)
(e1_aLob
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty (ExtractError Src Void)))
(e2_aLq9
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty (ExtractError Src Void))))
`cast` (Sym (N:ExtractErrors[0] <Src>_R <Void>_R)
:: NonEmpty (ExtractError Src Void)
~R# ExtractErrors Src Void);
Success ds1_aLqc -> e1_aLob
} } in
jump $j_s13uy e1_XLFQ;
Success a1_aLoe ->
case sc_s121d b2_iLug of {
Failure e1_aLqj -> jump $j_s13uy e1_aLqj;
Success x_aLqm ->
let {
a1_XLFX :: Digit (Node (Elem b_XLt1))
[LclId,
Unf=Unf{Src=<vanilla>, TopLvl=False, Value=True,
ConLike=True, WorkFree=True, Expandable=True,
Guidance=IF_ARGS [] 10 30}]
a1_XLFX = Two @ (Node (Elem b_XLt1)) a1_aLoe x_aLqm } in
jump $j_s13uz a1_XLFX
}
};
Three a2_iLuj b2_iLuk c_iLul ->
case lvl_sZFi
@ (Node (Elem b_XLt1))
@ (Digit (Node (Elem b_XLt1)))
(case sc_s121d a2_iLuj of {
Failure e1_aLob ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1) -> Digit (Node (Elem b_XLt1)))
(case sc_s121d b2_iLuk of {
Failure e2_aLq9 ->
($fSemigroupNonEmpty_$c<>
@ (ExtractError Src Void)
(e1_aLob
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty
(ExtractError Src Void)))
(e2_aLq9
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty
(ExtractError Src Void))))
`cast` (Sym (N:ExtractErrors[0] <Src>_R <Void>_R)
:: NonEmpty (ExtractError Src Void)
~R# ExtractErrors Src Void);
Success ds1_aLqc -> e1_aLob
});
Success a1_aLoe ->
case sc_s121d b2_iLuk of {
Failure e1_aLqj ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1) -> Digit (Node (Elem b_XLt1)))
e1_aLqj;
Success x_aLqm ->
Success
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1) -> Digit (Node (Elem b_XLt1)))
(Three @ (Node (Elem b_XLt1)) a1_aLoe x_aLqm)
}
})
(sc_s121d c_iLul)
of {
Failure e1_aLob -> jump $j_s13uy e1_aLob;
Success a1_aLoe -> jump $j_s13uz a1_aLoe
};
Four a2_iLuo b2_iLup c_iLuq d_iLur ->
case lvl_sZFi
@ (Node (Elem b_XLt1))
@ (Digit (Node (Elem b_XLt1)))
(lvl_sZFi
@ (Node (Elem b_XLt1))
@ (Node (Elem b_XLt1) -> Digit (Node (Elem b_XLt1)))
(case sc_s121d a2_iLuo of {
Failure e1_aLob ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1)
-> Node (Elem b_XLt1)
-> Digit (Node (Elem b_XLt1)))
(case sc_s121d b2_iLup of {
Failure e2_aLq9 ->
($fSemigroupNonEmpty_$c<>
@ (ExtractError Src Void)
(e1_aLob
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty
(ExtractError Src Void)))
(e2_aLq9
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty
(ExtractError Src Void))))
`cast` (Sym (N:ExtractErrors[0]
<Src>_R <Void>_R)
:: NonEmpty (ExtractError Src Void)
~R# ExtractErrors Src Void);
Success ds1_aLqc -> e1_aLob
});
Success a1_aLoe ->
case sc_s121d b2_iLup of {
Failure e1_aLqj ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1)
-> Node (Elem b_XLt1)
-> Digit (Node (Elem b_XLt1)))
e1_aLqj;
Success x_aLqm ->
Success
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1)
-> Node (Elem b_XLt1)
-> Digit (Node (Elem b_XLt1)))
(Four @ (Node (Elem b_XLt1)) a1_aLoe x_aLqm)
}
})
(sc_s121d c_iLuq))
(sc_s121d d_iLur)
of {
Failure e1_aLob -> jump $j_s13uy e1_aLob;
Success a1_aLoe -> jump $j_s13uz a1_aLoe
}
})
(case sf_iLu8 of {
One a2_iLuT ->
fmap
@ (Validation (ExtractErrors Src Void))
sc_s121b
@ (Node (Elem b_XLt1))
@ (Digit (Node (Elem b_XLt1)))
(One @ (Node (Elem b_XLt1)))
(sc_s121d a2_iLuT);
Two a2_iLuW b2_iLuX ->
case sc_s121d a2_iLuW of {
Failure e1_aLob ->
Failure
@ (ExtractErrors Src Void)
@ (Digit (Node (Elem b_XLt1)))
(case sc_s121d b2_iLuX of {
Failure e2_aLq9 ->
($fSemigroupNonEmpty_$c<>
@ (ExtractError Src Void)
(e1_aLob
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty (ExtractError Src Void)))
(e2_aLq9
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty (ExtractError Src Void))))
`cast` (Sym (N:ExtractErrors[0] <Src>_R <Void>_R)
:: NonEmpty (ExtractError Src Void)
~R# ExtractErrors Src Void);
Success ds1_aLqc -> e1_aLob
});
Success a1_aLoe ->
case sc_s121d b2_iLuX of {
Failure e1_aLqj ->
Failure
@ (ExtractErrors Src Void)
@ (Digit (Node (Elem b_XLt1)))
e1_aLqj;
Success x_aLqm ->
Success
@ (ExtractErrors Src Void)
@ (Digit (Node (Elem b_XLt1)))
(Two @ (Node (Elem b_XLt1)) a1_aLoe x_aLqm)
}
};
Three a2_iLv0 b2_iLv1 c_iLv2 ->
lvl_sZFi
@ (Node (Elem b_XLt1))
@ (Digit (Node (Elem b_XLt1)))
(case sc_s121d a2_iLv0 of {
Failure e1_aLob ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1) -> Digit (Node (Elem b_XLt1)))
(case sc_s121d b2_iLv1 of {
Failure e2_aLq9 ->
($fSemigroupNonEmpty_$c<>
@ (ExtractError Src Void)
(e1_aLob
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty (ExtractError Src Void)))
(e2_aLq9
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty (ExtractError Src Void))))
`cast` (Sym (N:ExtractErrors[0] <Src>_R <Void>_R)
:: NonEmpty (ExtractError Src Void)
~R# ExtractErrors Src Void);
Success ds1_aLqc -> e1_aLob
});
Success a1_aLoe ->
case sc_s121d b2_iLv1 of {
Failure e1_aLqj ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1) -> Digit (Node (Elem b_XLt1)))
e1_aLqj;
Success x_aLqm ->
Success
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1) -> Digit (Node (Elem b_XLt1)))
(Three @ (Node (Elem b_XLt1)) a1_aLoe x_aLqm)
}
})
(sc_s121d c_iLv2);
Four a2_iLv5 b2_iLv6 c_iLv7 d_iLv8 ->
lvl_sZFi
@ (Node (Elem b_XLt1))
@ (Digit (Node (Elem b_XLt1)))
(lvl_sZFi
@ (Node (Elem b_XLt1))
@ (Node (Elem b_XLt1) -> Digit (Node (Elem b_XLt1)))
(case sc_s121d a2_iLv5 of {
Failure e1_aLob ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1)
-> Node (Elem b_XLt1) -> Digit (Node (Elem b_XLt1)))
(case sc_s121d b2_iLv6 of {
Failure e2_aLq9 ->
($fSemigroupNonEmpty_$c<>
@ (ExtractError Src Void)
(e1_aLob
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty (ExtractError Src Void)))
(e2_aLq9
`cast` (N:ExtractErrors[0] <Src>_R <Void>_R
:: ExtractErrors Src Void
~R# NonEmpty
(ExtractError Src Void))))
`cast` (Sym (N:ExtractErrors[0] <Src>_R <Void>_R)
:: NonEmpty (ExtractError Src Void)
~R# ExtractErrors Src Void);
Success ds1_aLqc -> e1_aLob
});
Success a1_aLoe ->
case sc_s121d b2_iLv6 of {
Failure e1_aLqj ->
Failure
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1)
-> Node (Elem b_XLt1)
-> Digit (Node (Elem b_XLt1)))
e1_aLqj;
Success x_aLqm ->
Success
@ (ExtractErrors Src Void)
@ (Node (Elem b_XLt1)
-> Node (Elem b_XLt1)
-> Digit (Node (Elem b_XLt1)))
(Four @ (Node (Elem b_XLt1)) a1_aLoe x_aLqm)
}
})
(sc_s121d c_iLv7))
(sc_s121d d_iLv8)
})
Out of scope: lvl_sZFi
:: forall a b.
Validation (ExtractErrors Src Void) (a -> b)
-> Validation (ExtractErrors Src Void) a
-> Validation (ExtractErrors Src Void) b
[LclId, Arity=2]Full -dcore-lint message (7 MB)
I have reproduced the panic with both 8.8.2 and 8.6.5. GHC 8.4 and earlier don't show the panic. I haven't been able to build dhall with 8.10 due to build failures in its large dependency tree.
The Core seems to point at some Data.Sequence traversal, of which I see two in Dhall: 1, 2. In both cases, es is a Seq.
Reproduction steps
$ cabal get dhall-1.29.0
$ cd dhall-1.29.0
$ cabal build -O2 --ghc-options -dcore-lint