[GHC] #11524: Something is amiss with quantification in pattern synonym type signatures
GHC
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Mon Feb 1 22:56:39 UTC 2016
#11524: Something is amiss with quantification in pattern synonym type signatures
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Reporter: bgamari | Owner:
Type: bug | Status: new
Priority: high | Milestone: 8.0.1
Component: Compiler (Type | Version: 8.0.1-rc1
checker) |
Resolution: | Keywords:
Operating System: Unknown/Multiple | Architecture:
Type of failure: GHC rejects | Unknown/Multiple
valid program | Test Case:
Blocked By: | Blocking:
Related Tickets: | Differential Rev(s):
Wiki Page: |
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Comment (by niteria):
Better trace with `ghc-stage2`:
{{{
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 8.1.20160128 for x86_64-unknown-linux):
ASSERT failed!
CallStack (from ImplicitParams):
assertPprPanic, called at compiler/types/TyCoRep.hs:1932:51 in
ghc:TyCoRep
checkValidSubst, called at compiler/types/TyCoRep.hs:1981:17 in
ghc:TyCoRep
substTys, called at compiler/types/TyCoRep.hs:2002:14 in ghc:TyCoRep
substTheta, called at compiler/typecheck/TcPatSyn.hs:254:57 in
ghc:TcPatSyn
in_scope InScope {k_aB3 k_aB8 a_aB9 b_aBa}
tenv [auD :-> a_aB9[tau:5], auE :-> b_aBa[tau:5],
aB2 :-> k_aB8[tau:5]]
cenv []
tys [fun_auC[sk] ~ a_auD[sk] b_auE[sk]]
cos []
needInScope [auC :-> fun_auC[sk], aB3 :-> k_aB3[tau:1]]
}}}
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11524#comment:3>
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