panic! (the 'impossible' happened) on ‘deriving instance lowercase_name a’
This bogus code:
{-# LANGUAGE StandaloneDeriving #-}
deriving instance lowercase_name a
causes current GHC HEAD to panic:
ghc: panic! (the 'impossible' happened)
(GHC version 7.3.20110927 for x86_64-unknown-linux):
nameModule lowercase_name{tv aar}
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
I also tested GHC 7.0.3, which correctly diagnosed the problem:
crash.hs:2:19: Malformed instance header: lowercase_name a
Trac metadata
Trac field | Value |
---|---|
Version | 7.3 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
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Blocking | |
CC | |
Operating system | |
Architecture |