GHCi 8.0.1 panic with PatternSynonyms
Loading this code:
{-# LANGUAGE PatternSynonyms #-}
data D1 = MkD1 ()
data D2 = MkD2 D1
pattern P1 x = MkD1 x
pattern P2 x = MkD2 (P1 x)
in GHCi 8.0.1 results in the following panic:
$ ghci Broken.hs
GHCi, version 8.0.1: http://www.haskell.org/ghc/ :? for help
[1 of 1] Compiling Main ( Broken.hs, interpreted )
ghc: panic! (the 'impossible' happened)
(GHC version 8.0.1 for x86_64-unknown-linux):
kindPrimRep.go rep_a18s
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
>
The unique name in the error message (rep_a18s
) seems to be consistent between executions, but varies after :reload
ing.
The panic does not occur when the module is simply compiled with ghc
; it only occurs when loaded into ghci
.
According to Gergő Érdi, who is CCed, the error does not occur in GHCi 7.10.3
Trac metadata
Trac field | Value |
---|---|
Version | 8.0.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | GHCi |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | cactus |
Operating system | |
Architecture |