Panic while type checking expression using function with context holes
module Bug where
holey :: _ => _
holey = undefined
useHoley = holey True
$ ghc Bug.hs
[1 of 1] Compiling Bug ( Bug.hs, Bug.o )
Bug.hs:3:10:
Found hole ‘_’ with inferred constraints: ()
To use the inferred type, enable PartialTypeSignatures
In the type signature for ‘holey’: _ => _
Bug.hs:3:15:
Found hole ‘_’ with type: w_1
Where: ‘w_1’ is a rigid type variable bound by
the inferred type of holey :: w_1 at Bug.hs:4:1
To use the inferred type, enable PartialTypeSignatures
In the type signature for ‘holey’: _ => _
Bug.hs:6:12:
Couldn't match expected type ‘Bool -> t0’ with actual type ‘w_’
‘w_’ is untouchable
inside the constraints ()
bound by the inferred type of useHoley :: t0
at Bug.hs:6:1-21ghc: panic! (the 'impossible' happened)
(GHC version 7.10.3 for x86_64-unknown-linux):
No skolem info: w__alO[sk]
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 7.10.3
Trac metadata
Trac field |
Value |
Version |
7.10.3 |
Type |
Bug |
TypeOfFailure |
OtherFailure |
Priority |
normal |
Resolution |
Unresolved |
Component |
Compiler |
Test case |
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Differential revisions |
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BlockedBy |
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Related |
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Blocking |
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CC |
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Operating system |
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Architecture |
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